ALBERT

All Library Books, journals and Electronic Records Telegrafenberg

Your email was sent successfully. Check your inbox.

An error occurred while sending the email. Please try again.

Proceed reservation?

Export
Filter
  • Inorganic Chemistry  (7,397)
  • LUNAR AND PLANETARY EXPLORATION  (3,213)
  • Physics  (2,789)
  • ASTRONOMY
  • 2020-2024  (131)
  • 1980-1984  (11,111)
  • 1930-1934  (3,890)
Collection
Keywords
Language
Years
Year
  • 101
    Publication Date: 2024-04-04
    Description: Physics
    Keywords: Physics ; bic Book Industry Communication::P Mathematics & science::PH Physics ; thema EDItEUR::P Mathematics and Science::PH Physics
    Language: English
    Format: image/jpeg
    Format: image/jpeg
    Format: image/jpeg
    Format: image/jpeg
    Format: image/jpeg
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 102
    facet.materialart.
    Unknown
    Frontiers Media SA
    Publication Date: 2024-04-04
    Description: The Frontiers in Chemistry Editorial Office team are delighted to present the inaugural “Frontiers in Chemistry: Rising Stars” article collection, showcasing the high-quality work of internationally recognized researchers in the early stages of their independent careers. All Rising Star researchers featured within this collection were individually nominated by the Journal’s Chief Editors in recognition of their potential to influence the future directions in their respective fields. The work presented here highlights the diversity of research performed across the entire breadth of the chemical sciences, and presents advances in theory, experiment and methodology with applications to compelling problems. This Editorial features the corresponding author(s) of each paper published within this important collection, ordered by section alphabetically, highlighting them as the great researchers of the future. The Frontiers in Chemistry Editorial Office team would like to thank each researcher who contributed their work to this collection. We would also like to personally thank our Chief Editors for their exemplary leadership of this article collection; their strong support and passion for this important, community-driven collection has ensured its success and global impact.
    Keywords: Green and Sustainable Chemistry ; Analytical Chemistry ; Theoretical and Computational Chemistry ; Polymer Chemistry ; Medicinal and Pharmaceutical Chemistry ; Organic Chemistry ; Nanoscience ; Catalysis and Photocatalysis ; Supramolecular Chemistry ; Electrochemistry ; Inorganic Chemistry ; Chemical Biology ; thema EDItEUR::P Mathematics and Science::PD Science: general issues
    Language: English
    Format: image/jpeg
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 103
    facet.materialart.
    Unknown
    Taylor & Francis | CRC Press
    Publication Date: 2024-04-04
    Description: In this book, the author convinces that Sir Arthur Stanley Eddington had things a little bit wrong, as least as far as physics is concerned. He explores the theory of groups and Lie algebras and their representations to use group representations as labor-saving tools.
    Keywords: Physics ; thema EDItEUR::P Mathematics and Science::PH Physics
    Language: English
    Format: image/jpeg
    Format: image/jpeg
    Format: image/jpeg
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 104
    facet.materialart.
    Unknown
    Taylor & Francis | CRC Press
    Publication Date: 2024-04-05
    Description: A unified theory embracing all physical phenomena is a major goal of theoretical physics. In the early 1980s, many physicists looked to eleven-dimensional supergravity in the hope that it might provide that elusive superunified theory. In 1984 supergravity was knocked off its pedestal by ten-dimensional superstrings, one-dimensional objects whose v
    Keywords: Nuclear physics ; Physics ; thema EDItEUR::P Mathematics and Science::PH Physics::PHN Nuclear physics ; thema EDItEUR::P Mathematics and Science::PH Physics
    Language: English
    Format: image/jpeg
    Format: image/jpeg
    Format: image/jpeg
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 105
    facet.materialart.
    Unknown
    Taylor & Francis | CRC Press
    Publication Date: 2024-04-05
    Description: This book provides a thorough introduction to the phenomenology of heavy flavour physics, those working on the B-factories, LHCb, BTeV, HERA and the Tevatron. It explains how heavy quark theory could be implemented on the lattice, and discusses the status of CP-violation in the neutral kaon system.
    Keywords: Nuclear physics ; Physics ; thema EDItEUR::P Mathematics and Science::PH Physics::PHN Nuclear physics ; thema EDItEUR::P Mathematics and Science::PH Physics
    Language: English
    Format: image/jpeg
    Format: image/jpeg
    Format: image/jpeg
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 106
    Publication Date: 2024-04-07
    Description: Climate Change; Energy Efficiency; Remote Sensing; Photogrammetry; Physics
    Keywords: Climate Change ; Energy Efficiency ; Remote Sensing ; Photogrammetry ; Physics ; thema EDItEUR::K Economics, Finance, Business and Management::KC Economics::KCV Economics of specific sectors::KCVG Environmental economics ; thema EDItEUR::P Mathematics and Science::PH Physics::PHH Thermodynamics and heat
    Language: English
    Format: image/jpeg
    Format: image/jpeg
    Format: image/jpeg
    Format: image/jpeg
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 107
    facet.materialart.
    Unknown
    De Gruyter | De Gruyter
    Publication Date: 2024-04-05
    Description: With applications in quantum field theory, general relativity and elementary particle physics, this three-volume work studies the invariance of differential operators under Lie algebras, quantum groups and superalgebras. This second volume covers quantum groups in their two main manifestations: quantum algebras and matrix quantum groups. The exposition covers both the general aspects of these and a great variety of concrete explicitly presented examples. The invariant q-difference operators are introduced mainly using representations of quantum algebras on their dual matrix quantum groups as carrier spaces. This is the first book that covers the title matter applied to quantum groups.
    Keywords: Science ; Physics ; Quantum Theory ; Mathematics ; thema EDItEUR::P Mathematics and Science::PH Physics::PHQ Quantum physics (quantum mechanics and quantum field theory) ; thema EDItEUR::P Mathematics and Science::PB Mathematics
    Language: English
    Format: image/jpeg
    Format: image/jpeg
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 108
    Publication Date: 2024-03-29
    Description: Niedrige Studienerfolgsquoten in den Studiengängen Physik und Lehramt Physik sind sowohl aus bildungspolitischer und institutioneller Sicht als auch aus individueller Perspektive erfolglos Studierender eine Herausforderung. Bisher gibt es nur wenige empirische Studien, die Gründe für niedrige Studienerfolgsquoten bestimmen. Von dieser Situation ausgehend, zielte diese Arbeit auf die Erfassung domänenspezifischer Eingangsvoraussetzungen von Studienanfängerinnen und -anfängern, um daraus mögliche Prädiktoren für einen Studienerfolg zu bestimmen. Den Kern der Arbeit bildet die Konzeption und Evaluation eines Testinstruments zu Studieneingangsvoraussetzungen. Das Instrument umfasst einen Vorwissenstest in Mathematik und Physik sowie einen Test zu domänenspezifischen Verhaltensweisen und Einstellungen. Das selbstentwickelte Instrument wurde bei N = 116 Studierenden eingesetzt, um die Prognosekraft der gemessenen Konstrukte auf einen möglichen Studienerfolg zu schätzen. Dabei zeigte sich der Physikteil des Vorwissenstests in Verbindung mit der Hochschulzugangsberechtigungsnote als signifikanter Prädiktor für den Studienerfolg gemessen am Studienverbleib nach drei Semestern. Dieses Ergebnis stellt im Wesentlichen eine Replikation bereits bekannter Erkenntnisse dar. Es konnten erste Hinweise gefunden werden, dass sich lernzielorientierte Einstellungen positiv auf den Studienerfolg auswirken können.
    Keywords: Social Science ; Statistics ; Education ; Science ; Physics ; thema EDItEUR::J Society and Social Sciences::JH Sociology and anthropology::JHB Sociology::JHBC Social research and statistics ; thema EDItEUR::J Society and Social Sciences::JN Education ; thema EDItEUR::P Mathematics and Science::PH Physics
    Language: German
    Format: image/jpeg
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 109
    facet.materialart.
    Unknown
    Springer Nature
    Publication Date: 2024-04-07
    Description: This open access book is written by world-recognized experts in the fields of applied superconductivity and superconducting accelerator magnet technologies. It provides a contemporary review and assessment of the experience in research and development of high-field accelerator dipole magnets based on Nb3Sn superconductor over the past five decades. The reader attains clear insight into the development and the main properties of Nb3Sn composite superconducting wires and Rutherford cables, and details of accelerator dipole designs, technologies and performance. Special attention is given to innovative features of the developed Nb3Sn magnets. The book concludes with a discussion of accelerator magnet needs for future circular colliders. ; Broadens our understanding of design and performance limits of high-field Nb3Sn accelerator magnets for a future very high energy hadron collider Offers beginners a concise overview of the relevant design concepts for a new generation of superconducting accelerator magnets based on Nb3Sn superconductor Illustrates the complete process of accelerator magnet design and fabrication Provides a contemporary review and assessment of the past experience with Nb3Sn high-field dipole accelerator magnets Identifies the main open R&D issues for Nb3Sn high-field dipole magnets
    Keywords: Physics ; Particle acceleration ; Physical measurements ; Measurement    ; Machinery ; Atoms ; Physics ; thema EDItEUR::P Mathematics and Science::PD Science: general issues::PDD Scientific standards, measurement etc ; thema EDItEUR::P Mathematics and Science::PH Physics::PHM Atomic and molecular physics ; thema EDItEUR::P Mathematics and Science::PH Physics::PHP Particle and high-energy physics ; thema EDItEUR::T Technology, Engineering, Agriculture, Industrial processes::TG Mechanical engineering and materials::TGB Mechanical engineering::TGBN Engines and power transmission
    Language: English
    Format: image/jpeg
    Format: image/jpeg
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 110
    facet.materialart.
    Unknown
    Taylor & Francis | CRC Press
    Publication Date: 2024-04-05
    Description: An Introduction to the Standard Model of Particle Physics familiarizes readers with what is considered tested and accepted and in so doing, gives them a grounding in particle physics in general. Whenever possible, Dr. Mann takes an historical approach showing how the model is linked to the physics that most of us have learned in less challenging ar
    Keywords: Nuclear physics ; Physics ; thema EDItEUR::P Mathematics and Science::PH Physics::PHN Nuclear physics ; thema EDItEUR::P Mathematics and Science::PH Physics
    Language: English
    Format: image/jpeg
    Format: image/jpeg
    Format: image/jpeg
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 111
    Publication Date: 2024-03-30
    Description: This book summarizes results of longstanding research and scientific contributions from many projects and relevant working groups. It collects and evaluates wind and wave climate projections under changing climate having design needs and marine safety in focus. Potential impact of projected climate change in met-ocean conditions on ships and offshore structures is discussed and illustrated by an example of the expected wave climate change on tanker design.
    Keywords: GE1-350 ; TA1-2040 ; TK1-9971 ; TP248.13-248.65 ; TL1-4050 ; HG1-9999 ; QE1-996.5 ; RS1-441 ; TA401-492 ; Statistics for Engineering ; Computer Science ; Climate Change Management and Policy ; Chemistry and Earth Sciences ; Reliability ; Safety and Risk ; Physics ; Quality Control ; thema EDItEUR::K Economics, Finance, Business and Management::KC Economics::KCV Economics of specific sectors::KCVG Environmental economics
    Language: English
    Format: application/octet-stream
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 112
    facet.materialart.
    Unknown
    Springer Nature
    Publication Date: 2024-04-04
    Description: This open access textbook takes the reader step-by-step through the concepts of mechanics in a clear and detailed manner. Mechanics is considered to be the core of physics, where a deep understanding of the concepts is essential in understanding all branches of physics. Many proofs and examples are included to help the reader grasp the fundamentals fully, paving the way to deal with more advanced topics. After solving all of the examples, the reader will have gained a solid foundation in mechanics and the skills to apply the concepts in a variety of situations. The book is useful for undergraduate students majoring in physics and other science and engineering disciplines. It can also be used as a reference for more advanced levels.
    Keywords: Physics ; Mechanics ; Mechanical engineering ; Elementary particles (Physics) ; Quantum field theory ; bic Book Industry Communication::P Mathematics & science::PH Physics::PHD Classical mechanics ; bic Book Industry Communication::P Mathematics & science::PH Physics::PHQ Quantum physics (quantum mechanics & quantum field theory) ; bic Book Industry Communication::T Technology, engineering, agriculture::TG Mechanical engineering & materials::TGB Mechanical engineering ; thema EDItEUR::P Mathematics and Science::PH Physics::PHD Classical mechanics ; thema EDItEUR::P Mathematics and Science::PH Physics::PHQ Quantum physics (quantum mechanics and quantum field theory) ; thema EDItEUR::T Technology, Engineering, Agriculture, Industrial processes::TG Mechanical engineering and materials::TGB Mechanical engineering
    Language: English
    Format: image/jpeg
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 113
    facet.materialart.
    Unknown
    Logos Verlag Berlin | Logos Verlag Berlin
    Publication Date: 2024-04-04
    Description: Die Teilchenphysik als Teilgebiet der modernen Physik gewinnt zunehmend an Bedeutung im schulischen Physikunterricht. In dieser Arbeit wird erstmalig das von Lehrkräften benötigte Fachwissen zur Teilchenphysik modelliert, wobei Fachwissen als ein Teil des Professionswissens verstanden wird. Als Fachwissensdimensionen werden die Inhaltsbereiche und die Wissensarten in den Fokus genommen, für welche jeweils Subfacetten identifiziert und präzise beschrieben werden. Nach einem überblick über die wesentlichen Ideen der Teilchenphysik wird in der Arbeit die sukzessive Modellierung des Fachwissens im Rahmen einer qualitativ und quantitativ angelegten Delphi-Studie vorgestellt. In drei Befragungsrunden wurden zwischen 35 und 65 internationale Expertinnen und Experten aus der teilchenphysikbezogenen Forschung (Fachwissenschaft und Fachdidaktik) und öffentlichkeitsarbeit (u.a. Wissenschaftsjournalismus) sowie erfahrene Lehrkräfte zu den für das Fachwissen relevanten Themen der Teilchenphysik befragt. Empirische Analysen der Befragungsrunden ergaben, dass sich die Dimension Inhaltsbereiche im deklarativen Wissen aus zehn teilchenphysikalischen Themen (z.B. Teilchen in der Hochenergiephysik, die vier fundamentalen Wechselwirkungen) zusammensetzt, von welchen sechs als besonders relevant eingeschätzt wurden. Im Anschluss an die letzte Befragungsrunde wurde theoriegeleitet eine erste Modellierung der Inhaltsbereiche für die Wissensarten des prozeduralen und konditionalen Wissens vorgenommen.
    Keywords: Science ; Education ; Science ; Physics ; thema EDItEUR::P Mathematics and Science::PD Science: general issues ; thema EDItEUR::J Society and Social Sciences::JN Education ; thema EDItEUR::P Mathematics and Science::PH Physics
    Language: English
    Format: image/jpeg
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 114
    facet.materialart.
    Unknown
    Springer Nature
    Publication Date: 2024-04-04
    Description: This open access book, published in the Soft and Biological Matter series, presents an introduction to selected research topics in the broad field of flowing matter, including the dynamics of fluids with a complex internal structure -from nematic fluids to soft glasses- as well as active matter and turbulent phenomena. Flowing matter is a subject at the crossroads between physics, mathematics, chemistry, engineering, biology and earth sciences, and relies on a multidisciplinary approach to describe the emergence of the macroscopic behaviours in a system from the coordinated dynamics of its microscopic constituents. Depending on the microscopic interactions, an assembly of molecules or of mesoscopic particles can flow like a simple Newtonian fluid, deform elastically like a solid or behave in a complex manner. When the internal constituents are active, as for biological entities, one generally observes complex large-scale collective motions. Phenomenology is further complicated by the invariable tendency of fluids to display chaos at the large scales or when stirred strongly enough. This volume presents several research topics that address these phenomena encompassing the traditional micro-, meso-, and macro-scales descriptions, and contributes to our understanding of the fundamentals of flowing matter. This book is the legacy of the COST Action MP1305 “Flowing Matter”.
    Keywords: Physics ; Amorphous substances ; Complex fluids ; Fluids ; Fluid mechanics ; Chemical engineering ; thema EDItEUR::P Mathematics and Science::PH Physics::PHD Classical mechanics::PHDF Physics: Fluid mechanics ; thema EDItEUR::P Mathematics and Science::PH Physics::PHF Materials / States of matter ; thema EDItEUR::T Technology, Engineering, Agriculture, Industrial processes::TD Industrial chemistry and manufacturing technologies::TDC Industrial chemistry and chemical engineering ; thema EDItEUR::T Technology, Engineering, Agriculture, Industrial processes::TG Mechanical engineering and materials::TGM Materials science::TGMF Engineering: Mechanics of fluids ; thema EDItEUR::P Mathematics and Science::PH Physics::PHD Classical mechanics::PHDF Physics: Fluid mechanics ; thema EDItEUR::P Mathematics and Science::PH Physics::PHF Materials / States of matter ; thema EDItEUR::T Technology, Engineering, Agriculture, Industrial processes::TD Industrial chemistry and manufacturing technologies::TDC Industrial chemistry and chemical engineering ; thema EDItEUR::T Technology, Engineering, Agriculture, Industrial processes::TG Mechanical engineering and materials::TGM Materials science::TGMF Engineering: Mechanics of fluids
    Language: English
    Format: image/jpeg
    Format: image/jpeg
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 115
    Publication Date: 2024-04-04
    Description: Ein zentrales Ziel der fachdidaktischen Forschung stellt die Verbesserung schulischen Unterrichts dar. Eine Transferstrategie zur flächendeckenden Verbreitung wissenschaftlicher Erkenntnisse bildet die Bereitstellung evidenzbasierter, innovativer materialgestützter Unterrichtskonzeptionen. Allerdings fällt das Materialnutzungsverhalten von Lehrkräften individuell sehr unterschiedlich aus, wobei das Zusammenspiel verschiedener Einflussfaktoren auf die Materialnutzung bislang wenig erforscht ist. Ziel der vorliegenden Arbeit ist es daher, dieses Wirkgefüge unter authentischen Bedingungen genauer zu untersuchen. Dazu wurde kriteriengeleitet eine evidenzbasierte, fachdidaktisch innovative Unterrichtskonzeption ausgewählt (das Münchener Unterrichtskonzept zur Quantenmechanik) und den teilnehmenden Lehrkräften fakultativ zur Verfügung gestellt. Mittels eines qualitativen Forschungsansatzes wurden elf Lehrkräfte bei der Implementierung des Konzepts durch ein Interview zu Beginn und am Ende einer Unterrichtsreihe zur Quantenmechanik sowie zwei Unterrichtsbeobachtungen mit je einem anschließenden stimulated recall begleitet. Aus den Ergebnissen folgt, dass die Probanden sich überwiegend heuristisch mit der Konzeption auseinandersetzten und lediglich Elemente auf Sichtstrukturebene implementierten. Das nachgewiesene Wirksamkeitspotential von evidenzbasierten, innovativen Unterrichtskonzeptionen scheint sich folglich lediglich unter bestimmten Bedingungsfaktoren zu entfalten.
    Keywords: Science ; Education ; Science ; Physics ; thema EDItEUR::P Mathematics and Science::PD Science: general issues ; thema EDItEUR::J Society and Social Sciences::JN Education ; thema EDItEUR::P Mathematics and Science::PH Physics
    Language: German
    Format: image/jpeg
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 116
    Publication Date: 2022-01-31
    Description: By creating this comic, Living Science joins the celebrations of the 100th anniversary of the expeditions to the island of Príncipe in São Tomé e Príncipe, and Sobral, in Brazil, which allowed proof of the theory of General Relativity previously predicted by Albert Einstein. This comic will be disseminated and distributed on a large scale and aims to the presentation of the theory of General Relativity, using language understandable throughout the public. In addition, it is intended that the general public be able to value the expeditions made to Island of Príncipe and Sobral by astronomers portrayed here.
    Keywords: Science communication ; History of science ; Astronomy ; Physics
    Language: Portuguese
    Format: image/jpeg
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 117
    facet.materialart.
    Unknown
    Taylor & Francis | CRC Press
    Publication Date: 2024-04-04
    Description: Cosmology in Gauge Field Theory and String Theory focuses on the cosmological implications of the gauge theories of particle physics and of string theory. The book first examines the universe's series of phase transitions in which the successive gauge symmetries of the higher-temperature phase were spontaneously broken after the big bang, discussing relics of these phase transitions, more generic relics (baryons, neutrinos, axions), and supersymmetric particles (neutralinos and gravitinos). The author next studies supersymmetric theory, supergravity theory, and the constraints on the underlying field theory of the universe's inflationary era. The book concludes with a discussion of black hole solutions of the supergravity theory that approximates string theory at low energies and the insight that string theory affords into the microscopic origin of the Bekenstein-Hawking entropy. Cosmology in Gauge Field Theory and String Theory provides a modern introduction to these important problems from a particle physicist's perspective. It is intended as an introductory textbook for a first course on the subject at a graduate level.
    Keywords: Physics ; thema EDItEUR::P Mathematics and Science::PH Physics
    Language: English
    Format: image/jpeg
    Format: image/jpeg
    Format: image/jpeg
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 118
    Publication Date: 2023-12-20
    Description: Issues and insights from the fields of brain research, quantum mechanics, and evolutionary theory have passed into novels, and physicists and biologists often use rhetorical metaphors to communicate and even evoke their discoveries. The essays in this volume examine natural scientific themes in literary texts – such as the novels of Richard Powers, Can Hue, and Raoul Schrott – and the use of rhetoric and metaphor in the natural sciences.
    Keywords: PN1-6790 ; Literature ; Science ; Physics ; bic Book Industry Communication::D Literature & literary studies
    Language: German
    Format: application/octet-stream
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 119
    Publication Date: 2023-12-21
    Description: In the spring of 2011, a diverse group of scientists gathered at Cornell University to discuss their research into the nature and origin of biological information. This symposium brought together experts in information theory, computer science, numerical simulation, thermodynamics, evolutionary theory, whole organism biology, developmental biology, molecular biology, genetics, physics, biophysics, mathematics, and linguistics. This volume presents new research by those invited to speak at the conference. The contributors to this volume use their wide-ranging expertise in the area of biological information to bring fresh insights into the many explanatory difficulties associated with biological information. These authors raise major challenges to the conventional scientific wisdom, which attempts to explain all biological information exclusively in terms of the standard mutation/selection paradigm. Several clear themes emerged from these research papers: 1) Information is indispensable to our understanding of what life is; 2) Biological information is more than the material structures that embody it; 3) Conventional chemical and evolutionary mechanisms seem insufficient to fully explain the labyrinth of information that is life. By exploring new perspectives on biological information, this volume seeks to expand, encourage, and enrich research into the nature and origin of biological information. Contents: Session One — Information Theory & Biology: Introductory Comments (Robert J Marks II): Biological Information — What is It? (Werner Gitt, Robert Compton and Jorge Fernandez) A General Theory of Information Cost Incurred by Successful Search (William A Dembski, Winston Ewert and Robert J Marks II) Pragmatic Information (John W Oller, Jr) Limits of Chaos and Progress in Evolutionary Dynamics (William F Basener) Tierra: The Character of Adaptation (Winston Ewert, William A Dembski and Robert J Marks II) Multiple Overlapping Genetic Codes Profoundly Reduce the Probability of Beneficial Mutation (George Montañez, Robert J Marks II, Jorge Fernandez and John C Sanford) Entropy, Evolution and Open Systems (Granville Sewell) Information and Thermodynamics in Living Systems (Andy C McIntosh) Session Two — Biological Information and Genetic Theory: Introductory Comments (John C Sanford): Not Junk After All: Non-Protein-Coding DNA Carries Extensive Biological Information (Jonathan Wells) Can Purifying Natural Selection Preserve Biological Information? (Paul Gibson, John R Baumgardner, Wesley H Brewer and John C Sanford) Selection Threshold Severely Constrains Capture of Beneficial Mutations (John C Sanford, John R Baumgardner and Wesley H Brewer) Using Numerical Simulation to Test the “Mutation-Count” Hypothesis (Wesley H Brewer, John R Baumgardner and John C Sanford) Can Synergistic Epistasis Halt Mutation Accumulation? Results from Numerical Simulation (John R Baumgardner, Wesley H Brewer and John C Sanford) Computational Evolution Experiments Reveal a Net Loss of Genetic Information Despite Selection (Chase W Nelson and John C Sanford) Information Loss: Potential for Accelerating Natural Genetic Attenuation of RNA Viruses (Wesley H Brewer, Franzine D Smith and John C Sanford) DNA.EXE: A Sequence Comparison between the Human Genome and Computer Code (Josiah Seaman) Biocybernetics and Biosemiosis (Donald Johnson) Session Three — Theoretical Molecular Biology: Introductory Comments (Michael J Behe): An Ode to the Code: Evidence for Fine-Tuning in the Standard Codon Table (Jed C Macosko and Amanda M Smelser) A New Model of Intracellular Communication Based on Coherent, High-Frequency Vibrations in Biomolecules (L Dent) Getting There First: An Evolutionary Rate Advantage for Adaptive Loss-of-Function Mutations (Michael J Behe) The Membrane Code: A Carrier of Essential Biological Information That is Not Specified by DNA and is Inherited Apart from It (Jonathan Wells) Explaining Metabolic Innovation: Neo-Darwinism Versus Design (Douglas D Axe and Ann K Gauger) Session Four — Biological Information and Self-Organizational Complexity Theory: Introductory Comments (Bruce L Gordon): Evolution Beyond Entailing Law: The Roles of Embodied Information and Self Organization (Stuart Kauffman) Towards a General Biology: Emergence of Life and Information from the Perspective of Complex Systems Dynamics (Bruce H Weber) Readership: Academics, researchers, postgraduates and advanced undergraduates in bioinformatics. Biologists, mathematicians/statisticians, physicists and computer scientists.
    Keywords: T1-995 ; Molecular Biology ; Mutation/Selection Paradigm ; Numerical Simulation ; Mathematics ; Biophysics ; Physics ; Thermodynamics ; Information Theory ; Evolutionary Theory ; Computer Science ; Linguistics ; Genetics ; Developmental Biology ; Biological Information ; Whole Organism Biology ; bic Book Industry Communication::T Technology, engineering, agriculture::TB Technology: general issues
    Language: English
    Format: image/jpeg
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 120
    Publication Date: 2022-01-31
    Description: Physics and literature are two forms of knowing the world that are both complementary and contingent. Poetical-physical ways of writing and metaphors in physical theories are two sides of a coin. Interviews with Ulrike Draesner, Durs Grünbein, Michael Hampe, Jens Harder, Reinhard Jirgl, Thomas Lehr, Ulrich Woelk, and Juli Zeh enrich our knowledge of these two cultures through voices familiar with both sides.
    Keywords: PN1-6790 ; QC1-999 ; Literature ; Physics ; Interview
    Language: German
    Format: application/octet-stream
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 121
    Publication Date: 2024-04-04
    Description: This advanced textbook and reference is the first comprehensive and systematic review of all methods used for the measurement, correction, and control of the beam dynamics of modern particle accelerators. Based on material presented in several lectures at the US Particle Accelerator School, the text is intended for graduate students starting research or work in the field of beam physics. Relativistic beams in linear accelerators and storage rings provide the focus. After a review of linear optics, the text addresses basic and advanced techniques for beam control, plus a variety of methods for the manipulation of particle-beam properties. In each case, specific procedures are illustrated by examples from operational accelerators, e.g., CERN, DESY, SLAC, KEK, LBNL, and FNAL. The book also treats special topics such as injection and extraction methods, beam cooling, spin transport, and polarization. Problems and solutions enhance the book’s usefulness in graduate courses.
    Keywords: Physics ; Physics ; CERN ; DESY ; Particle accelerator ; Storage ring ; control ; measurement ; thema EDItEUR::P Mathematics and Science::PH Physics
    Language: English
    Format: image/jpeg
    Format: image/jpeg
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 122
    facet.materialart.
    Unknown
    Springer Nature
    Publication Date: 2024-04-07
    Description: This open access book provides a comprehensive toolbox of analysis techniques for ionospheric multi-satellite missions. The immediate need for this volume was motivated by the ongoing ESA Swarm satellite mission, but the tools that are described are general and can be used for any future ionospheric multi-satellite mission with comparable instrumentation. In addition to researching the immediate plasma environment and its coupling to other regions, such a mission aims to study the Earth’s main magnetic field and its anomalies caused by core, mantle, or crustal sources. The parameters for carrying out this kind of work are examined in these chapters. Besides currents, electric fields, and plasma convection, these parameters include ionospheric conductance, Joule heating, neutral gas densities, and neutral winds. ;
    Keywords: Physics ; Space sciences ; Atmospheric sciences ; Observations, Astronomical ; Astronomy—Observations ; Planetary science ; thema EDItEUR::P Mathematics and Science::PG Astronomy, space and time ; thema EDItEUR::P Mathematics and Science::PG Astronomy, space and time::PGS Solar system: the Sun and planets ; thema EDItEUR::R Earth Sciences, Geography, Environment, Planning::RB Earth sciences ; thema EDItEUR::T Technology, Engineering, Agriculture, Industrial processes::TT Other technologies and applied sciences::TTD Space science::TTDS Astronautics
    Language: English
    Format: image/jpeg
    Format: image/jpeg
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 123
    facet.materialart.
    Unknown
    Springer Nature
    Publication Date: 2024-04-04
    Description: This book by Helmut Wiedemann is a well-established, classic text, providing an in-depth and comprehensive introduction to the field of high-energy particle acceleration and beam dynamics. The present 4th edition has been significantly revised, updated and expanded. The newly conceived Part I is an elementary introduction to the subject matter for undergraduate students. Part II gathers the basic tools in preparation of a more advanced treatment, summarizing the essentials of electrostatics and electrodynamics as well as of particle dynamics in electromagnetic fields. Part III is an extensive primer in beam dynamics, followed, in Part IV, by an introduction and description of the main beam parameters and including a new chapter on beam emittance and lattice design. Part V is devoted to the treatment of perturbations in beam dynamics. Part VI then discusses the details of charged particle acceleration.
    Keywords: Physics ; Physics ; Accelerator Science and Technology ; Beam dynamics ; Beam physics ; Charged particle beams ; Charged particles dynamics ; Free electron laser ; Introduction to Particle Accelerators ; Physics of Particle Accelerators ; Synchrotron radiation ; US Accelerator Physics School ; thema EDItEUR::P Mathematics and Science::PH Physics ; thema EDItEUR::P Mathematics and Science::PH Physics
    Language: English
    Format: image/jpeg
    Format: image/jpeg
    Format: image/jpeg
    Format: image/jpeg
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 124
    Publication Date: 2024-04-05
    Description: Volume 1 of this revised and updated edition provides an accessible and practical introduction to the first gauge theory included in the Standard Model of particle physics: quantum electrodynamics (QED).The book includes self-contained presentations of electromagnetism as a gauge theory as well as relativistic quantum mechanics. It provides a uniqu
    Keywords: Nuclear physics ; Physics ; Quantum physics (quantum mechanics and quantum field theory) ; thema EDItEUR::P Mathematics and Science::PH Physics::PHN Nuclear physics ; thema EDItEUR::P Mathematics and Science::PH Physics ; thema EDItEUR::P Mathematics and Science::PH Physics::PHQ Quantum physics (quantum mechanics and quantum field theory)
    Language: English
    Format: image/jpeg
    Format: image/jpeg
    Format: image/jpeg
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 125
    Publication Date: 2024-04-05
    Description: Tensor network is a fundamental mathematical tool with a huge range of applications in physics, such as condensed matter physics, statistic physics, high energy physics, and quantum information sciences. This open access book aims to explain the tensor network contraction approaches in a systematic way, from the basic definitions to the important applications. This book is also useful to those who apply tensor networks in areas beyond physics, such as machine learning and the big-data analysis. Tensor network originates from the numerical renormalization group approach proposed by K. G. Wilson in 1975. Through a rapid development in the last two decades, tensor network has become a powerful numerical tool that can efficiently simulate a wide range of scientific problems, with particular success in quantum many-body physics. Varieties of tensor network algorithms have been proposed for different problems. However, the connections among different algorithms are not well discussed or reviewed. To fill this gap, this book explains the fundamental concepts and basic ideas that connect and/or unify different strategies of the tensor network contraction algorithms. In addition, some of the recent progresses in dealing with tensor decomposition techniques and quantum simulations are also represented in this book to help the readers to better understand tensor network. This open access book is intended for graduated students, but can also be used as a professional book for researchers in the related fields. To understand most of the contents in the book, only basic knowledge of quantum mechanics and linear algebra is required. In order to fully understand some advanced parts, the reader will need to be familiar with notion of condensed matter physics and quantum information, that however are not necessary to understand the main parts of the book. This book is a good source for non-specialists on quantum physics to understand tensor network algorithms and the related mathematics.
    Keywords: Physics ; Physics ; Quantum physics ; Quantum optics ; Statistical physics ; Machine learning ; Elementary particles (Physics) ; Quantum field theory ; thema EDItEUR::P Mathematics and Science::PH Physics::PHJ Optical physics ; thema EDItEUR::P Mathematics and Science::PH Physics::PHQ Quantum physics (quantum mechanics and quantum field theory) ; thema EDItEUR::P Mathematics and Science::PH Physics::PHS Statistical physics ; thema EDItEUR::P Mathematics and Science::PH Physics::PHU Mathematical physics ; thema EDItEUR::U Computing and Information Technology::UY Computer science::UYQ Artificial intelligence::UYQM Machine learning ; thema EDItEUR::P Mathematics and Science::PH Physics::PHJ Optical physics ; thema EDItEUR::P Mathematics and Science::PH Physics::PHQ Quantum physics (quantum mechanics and quantum field theory) ; thema EDItEUR::P Mathematics and Science::PH Physics::PHS Statistical physics ; thema EDItEUR::P Mathematics and Science::PH Physics::PHU Mathematical physics ; thema EDItEUR::U Computing and Information Technology::UY Computer science::UYQ Artificial intelligence::UYQM Machine learning
    Language: English
    Format: image/jpeg
    Format: image/jpeg
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 126
    facet.materialart.
    Unknown
    Coimbra University Press
    Publication Date: 2022-01-31
    Description: This work brings together various contributions from experts in very diverse areas of knowledge, to discuss the theme ‘Light’ from various points of view. The subjects gathered in this work come from the areas of Physics, Philosophy, Transcendence, Chemistry, Optics, Literature, History of Sciences, History, Geography, International Relations, Biology, Psychology, Art, Cinema and Photography, Medicine and Museology. The texts partially reflect the contents presented at the interdisciplinary colloquium ‘Visões da Luz’ held in October 2015, on the occasion of the International Year of Light 2015, under the aegis of III-UC and open to academia and society, to teachers of the Basic and Secondary Education.
    Keywords: Geography ; Chemistry ; Literature ; Geology ; Light ; Optics ; Biology ; History ; Physics
    Language: Portuguese
    Format: image/jpeg
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 127
    facet.materialart.
    Unknown
    Springer Nature
    Publication Date: 2021-02-10
    Description: This Open Access biography chronicles the life and achievements of the Norwegian engineer and physicist Rolf Widerøe. Readers who meet him in the pages of this book will wonder why he isn't better known. The first of Widerøe's many pioneering contributions in the field of accelerator physics was the betatron, the second, the linear accelerator, both summarized in a 27 page PhD. The betatron revolutionized the fields of cancer treatment through radiation therapy and also nondestructive testing; hospitals worldwide installed Widerøe's machine and today’s modern radiation treatment equipment is based on his inventions. The most recent renaissance of the linac provides unprecedented x-ray intensities at Free Electron Laser (FEL) facilities in operation and construction worldwide. . Widerøe’s story also includes a fair share of drama, particularly during World War II when both Germans and the Allies vied for his collaboration. Widerøe held leading positions in multinational industry groups and was one of the consultants for building the world's largest nuclear laboratory, CERN, in Switzerland. He gained over 200 patents, received several honorary doctorates and a number of international awards. The author, a professional writer and maker of TV documentaries, has gained access to hitherto restricted archives in several countries, which provided a wealth of new material and insights, in particular in relation to the war years. She tells here a gripping and illuminating story.
    Keywords: Popular works ; Physics ; Particle acceleration ; Cancer research ; Physics ; bic Book Industry Communication::M Medicine::MJ Clinical & internal medicine::MJC Diseases & disorders::MJCL Oncology ; bic Book Industry Communication::P Mathematics & science::PD Science: general issues::PDX History of science ; bic Book Industry Communication::P Mathematics & science::PD Science: general issues::PDZ Popular science ; bic Book Industry Communication::P Mathematics & science::PH Physics::PHP Particle & high-energy physics
    Language: English
    Format: image/jpeg
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 128
    facet.materialart.
    Unknown
    IntechOpen | IntechOpen
    Publication Date: 2024-04-04
    Description: This book describes the recent evolution of solid-state physics, which is primarily dedicated to examining the behavior of solids at the atomic scale. It also presents various state-of-the-art reviews and original contributions related to solid-state sciences. The book consists of four sections, namely, solid-state behavior, metastable materials, spintronics materials, and mechanics of deformable bodies. The authors’ contributions relating to solid-state behavior deal with the performance of solid matters pertaining to quantum mechanics, physical metallurgy, and crystallography. The authors’ contributions relating to metastable materials demonstrate the behavior of amorphous/bulk metallic glasses and some nonequilibrium materials. The authors’ contributions relating to spintronic materials explain the principles and equations underlying the physics, transport, and dynamics of spin in solid-state systems. The authors’ contributions relating to the mechanics of deformable bodies deal with applications of numeric and analytic solutions/models for solid-state structures under deformation. Key Features:Issues in solid-state physics, Lagrangian quantum mechanics,Quantum and thermal behavior of HCP crystals,Thermoelectric properties of semiconductors,Bulk metallic glasses and metastable atomic density determination,Applications of spintronics and Heusler alloys, 2D elastostatic, mathematical modeling and dynamic stiffness methods on deformable bodies.
    Keywords: Physics ; bic Book Industry Communication::P Mathematics & science::PH Physics ; thema EDItEUR::P Mathematics and Science::PH Physics
    Language: English
    Format: image/jpeg
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 129
    facet.materialart.
    Unknown
    Taylor & Francis | Routledge
    Publication Date: 2024-04-05
    Description: Introduction to Gauge Field Theory provides comprehensive coverage of modern relativistic quantum field theory, emphasizing the details of actual calculations rather than the phenomenology of the applications. Forming a foundation in the subject, the book assumes knowledge of relativistic quantum mechanics, but not of quantum field theory. The book
    Keywords: Nuclear physics ; Physics ; Quantum physics (quantum mechanics and quantum field theory) ; thema EDItEUR::P Mathematics and Science::PH Physics::PHN Nuclear physics ; thema EDItEUR::P Mathematics and Science::PH Physics ; thema EDItEUR::P Mathematics and Science::PH Physics::PHQ Quantum physics (quantum mechanics and quantum field theory)
    Language: English
    Format: image/jpeg
    Format: image/jpeg
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 130
    Publication Date: 2024-04-04
    Description: This eBook is a collection of articles from a Frontiers Research Topic. Frontiers Research Topics are very popular trademarks of the Frontiers Journals Series: they are collections of at least ten articles, all centered on a particular subject. With their unique mix of varied contributions from Original Research to Review Articles, Frontiers Research Topics unify the most influential researchers, the latest key findings and historical advances in a hot research area! Find out more on how to host your own Frontiers Research Topic or contribute to one as an author by contacting the Frontiers Editorial Office: frontiersin.org/about/contact
    Keywords: Fractional Differential Equations ; Real-World Applications ; Physics ; fractional calculus ; computational techniques ; Fractional order models ; thema EDItEUR::P Mathematics and Science::PD Science: general issues ; thema EDItEUR::P Mathematics and Science::PH Physics
    Language: English
    Format: image/jpeg
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 131
    facet.materialart.
    Unknown
    Springer Nature
    Publication Date: 2024-04-08
    Description: This open access book chronicles the rise of a new scientific paradigm offering novel insights into the age-old enigmas of existence. Over 300 years ago, the human mind discovered the machine code of reality: mathematics. By utilizing abstract thought systems, humans began to decode the workings of the cosmos. From this understanding, the current scientific paradigm emerged, ultimately discovering the gift of technology. Today, however, our island of knowledge is surrounded by ever longer shores of ignorance. Science appears to have hit a dead end when confronted with the nature of reality and consciousness. In this fascinating and accessible volume, James Glattfelder explores a radical paradigm shift uncovering the ontology of reality. It is found to be information-theoretic and participatory, yielding a computational and programmable universe.
    Keywords: Popular works ; Physics ; Epistemology ; Physics ; Statistical physics ; Dynamical systems ; Philosophy and science ; Philosophy ; thema EDItEUR::Q Philosophy and Religion::QD Philosophy::QDT Topics in philosophy::QDTK Philosophy: epistemology and theory of knowledge ; thema EDItEUR::Q Philosophy and Religion::QD Philosophy::QDX Popular philosophy ; thema EDItEUR::P Mathematics and Science::PD Science: general issues::PDA Philosophy of science ; thema EDItEUR::P Mathematics and Science::PD Science: general issues::PDX History of science ; thema EDItEUR::P Mathematics and Science::PD Science: general issues::PDZ Popular science ; thema EDItEUR::P Mathematics and Science::PH Physics::PHS Statistical physics ; thema EDItEUR::Q Philosophy and Religion::QD Philosophy::QDT Topics in philosophy::QDTK Philosophy: epistemology and theory of knowledge ; thema EDItEUR::Q Philosophy and Religion::QD Philosophy::QDX Popular philosophy ; thema EDItEUR::P Mathematics and Science::PD Science: general issues::PDA Philosophy of science ; thema EDItEUR::P Mathematics and Science::PD Science: general issues::PDX History of science ; thema EDItEUR::P Mathematics and Science::PD Science: general issues::PDZ Popular science ; thema EDItEUR::P Mathematics and Science::PH Physics::PHS Statistical physics
    Language: English
    Format: image/jpeg
    Format: image/jpeg
    Format: image/jpeg
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 132
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 117 (1984), S. 1940-1953 
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Charge-Transfer Complexes of Tetrathiafulvalene (TTF) with 1,2,5-Thiadiazolequinones1)The syntheses and the X-ray structure analyses of the charge-transfer complexes of tetrathiafulvalene (TTF) with naphtho[2,3-c][1,2,5]thiadiazole-4,9-dione (1 : 2) (2) and benzol[1,2-c: 4,5-c′]-bis[1,2,5]thiadiazole-4,8-dione (1 : 1) (4) are reported. In their crystal structures both compounds are built up by mixed columnar stacks of donors and acceptors, forming a characteristic packing motive for organic D-A complexes with properties of an electrical insulator.
    Notes: Es wird über die Synthese und die Einkristallröntgenstrukturanalysen der Charge-Transfer-Komplexe von Tetrathiafulvalen mit Naphtho[2,3-c][1,2,5]thiadiazol-4,9-dion (1 : 2) (2) und Benzo-[1,2-c: 4,5-c′]bis[1,2,5]thiadiazol-4,8-dion (1 : 1) (4) berichtet. Beide Verbindungen weisen in ihrer Kristallstruktur aus Donoren und Acceptoren gemischte kolumnare Stapel auf, ein charakteristisches Packungsmotiv organischer D-A-Komplexe mit elektrischen Isolatoreigenschaften.
    Additional Material: 7 Ill.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 133
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 117 (1984), S. 1973-1976 
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Generation of Nitrosyl Salts in Dry Organic MediaTrimethylsilyl halides (CH3)3SiX (2a - c, X = Cl, Br, I) are sufficiently electrophilic to cleave, in an equilibrium reaction, alkyl nitrites O = NOR (1a, b, R = i-C5H11, C2H5) with formation of O = NX (3a - c) and (CH3)3SiOR (4a, b). This reaction serves as a convenient in-situ-method to generate nitrosyl compounds NOX in chlorinated hydrocarbons as inert organic media.
    Additional Material: 1 Tab.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 134
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 117 (1984), S. 1954-1964 
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Iminoboranes from the Thermal Decomposition of DialkylazidoboranesIminoboranes RB = NR (1a - f) are formed by the thermal decomposition of azidoboranes R2BN3 (5a - f) in the gas phase or in solution. At low temperature, the iminoboranes 1b, d, e (R = iPr, iBu, sBu) can be trapped from the gas phase. They are characterized and brought to reaction as isolated species. Without other reactands, the iminoboranes dimerize or trimerize to form the cyclic products 2 or 3, respectively, or polymerize to the wax-like solids 4. Produced in solution below 100 °C, the iminoboranes are azidoborated by the educts 5 to give the (azidoboryl)amines 6 which are transformed into the borazines 3 at 160 - 180 °C. Iminoboranes undergo an ethyloboration with BEt3, a cycloaddition with PhN3, and in the absence of the strongly reactive R2BN3 a concurring cycloaddition and azidosilation with Me3SiN3 with formation of 7 - 10, respectively.
    Notes: Iminoborane RB = NR (1a - f) entstehen beim thermischen Zerfall von Azidoboranen R2BN3 (5a - f) in der Gasphase oder in Lösung. Die aus der Gasphase abgeschiedenen Produkte 1b, d, e (R = iPr, iBu, sBu) lassen sich bei tiefer Temperatur isolieren, charakterisieren und isoliert umsetzen. Mit sich selbst reagieren die in der Gasphase ergzeugten Iminoborane 1a - f unter Cyclodi-oder -trimerisierung oder unter Polymerisierung zu Produkten von Typ 2, 3 bzw. 4. In Lösung unterhalb 100 °C erzeugt, werden die Iminoborane von den Edukten 5 zu Produkten 6 azidoboriert; diese lassen sich bei 160 - 180 °C in Borazine 3 überführen. Iminoborane erfahren durch BEt3 eine Ethyloborierung zu 7, mit PhN3 eine Cycloaddition zu 8 und mit Me3SiN3 nebeneinander eine Cycloaddition zu 9 und eine Azidosilierung zu 10, sofern nicht das Edukt R2BN3 zugegen ist, das dem Azid Me3SiN3 in der Reaktivität gegenüber 1 überlegen ist.
    Additional Material: 6 Tab.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 135
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 117 (1984), S. 1965-1972 
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Azodesilylation - a Novel Aprotic Diazotization TechniqueNitrosyl compounds NOA (4a - e, A = Cl, Br, BF4, CF3SO3, I) - generated partially in situ from O = N - OR/(CH3)3SiA (7a, b, R = i-C5H11, C2H5/8a, b, e, A = Cl, Br, I) - react in aprotic organic media with N,N-bissilylated organylamines RN[Si(CH3)3]2 (3b, R = C6H5; 15, R = CH3) under generation of diazonium systems R - N2+ A- and formation of non-nucleophilic hexamethyldisiloxane (6b). This method represents the first nucleophile excluding diazotization technique on the basis of three-coordinated nitrogen and is termed „azodesilylation“.
    Notes: Nitrosylverbindungen NOA (4a - e, A = Cl, Br, BF4, CF3SO3, I) - teilweise in situ hergestellt aus O = N - OR/(CH3)3SiA (7a, b, R = i-C5H11, C2H5/8a, b, e, A = Cl, Br, I) - reagieren mit N,N-bissilylierten Organylaminen RN[Si(CH3)3]2 (3b, R = C6H5; 15, R = CH3) in aprotischen organischen Medien unter Bildung von Diazonium-Systemen R - N2+ A- und nicht-nucleophilem Hexamethyldisiloxan (6b). Diese Methode repräsentiert die erste, Nucleophile ausschließende Diazotierungstechnik auf der Basis von 3fach koordiniertem Stickstoff und wird als „Azodesilylierung“ bezeichnet.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 136
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 117 (1984), S. 1977-1979 
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Säurekatalysierte Cyclisierung des En-Produkts aus α-Pinen und PTADAluminiumchlorid-katalysierte Reaktion des En-Produkts 2 aus 4-Phenyl-4H-1,2,4-triazol-3,5-dion (PTAD) und α-Pinen (1), des 1-(6,6-Dimelthyl-2-methylenbicyclo[3.1.1]hept-3-yl)-4-phenyl-1,2,4-triazolidin-3,5-dions, ergab 3,8,8-Trimelthyl-N-phenyl-4,5-diazatricyclo[4.2.1.03,7]nonan-4,5-dicarboxamid (6) in 78% Ausbeute. Auch Bortrifluorid-etherat, trockener Chlorwasserstoff und p-Toluolsulfonsäure katalysieren die Cyclisierung von 2 zu 6, aber nicht in diesem Maße. Der Mechanismus der Cyclisierung wird über eine Gerüstumlagerung der Carbenium-Ionen-Zwischenstufen gedeutet.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 137
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 117 (1984), S. 1980-1981 
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Chain Lengthening of Tetrafluoro-1,2-ethanedisulfenyl Dichloride by the Reaction with Hydrogen PeroxideThe reaction of the little compound ClSCF2CF2SCl (1) with aqueous H2O2 results in the formation of ClS2CF2CF2SSCF2CF2SO2Cl(2), which is characterized on the basis of 19F NMR, mass, IR, and Raman spectroscopy.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 138
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 117 (1984), S. 1982-1986 
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Fluorination of Adamantane Derivatives with Oxygen DifluorideFluorination of adamantane and adamantane derivatives 1 with OF2 in the absence of an HF-trap gives fluoroadamantanes 2 and adamantanols 3 in varying amounts. Increasing yields of 2 are obtained in the presence of Na2CO3 as an HF-trap. In addition, the fluorooxahomoadamantanes 4b and e are formed in this reaction. The fluorination of adamantanone (5) with OF2 leads to analogous products.
    Additional Material: 2 Tab.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 139
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 117 (1984), S. 1987-1990 
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Photoelektronenspektren einiger Reduktionsprodukte von [2.2]ParacyclophanAnhand des He(I)-Photoelektronen(PE)-Spektrums von 2,3′,5,6′-Tetrahydro[2.2]paracyclophan (2) wird gezeigt, daß die Through-Bond-Wechselwirkung zwischen den Sechsringen klein, innerhalb der Cyclohexadienringe aber groß ist. Über die PE-Spektren der weiteren Hydrierungsprodukte 3 und 4 wird berichtet.
    Additional Material: 2 Ill.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 140
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 117 (1984), S. 1991-1993 
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Syntheses with Cyclobutadienes, 51). 5,5,6,6-Tetracyano-5,6-dihydro-Dewar benzene/3,3,4,4-Tetracyano-3,4-dihydrobenzvalene - a Novel Equilibrating SystemThe cyclobutadiene 3 reacts with tetracyanoethylene to give a 1 : 1-mixture of the dihydro-Dewar benzene 5 and the dihydrobenzvalene 6, which can be separated by crystallisation. In deuteriochloroform solution 5 and 6 are in a 1 : 1 equilibrium.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 141
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 117 (1984) 
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 142
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 117 (1984), S. 2275-2286 
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Electron Rich Heterocycles as Donor Groups in Fluorescent DyesThe synthesis of N-methylphthalimides substituted with the donor groups pyrazole, triazole, benzotriazole, and naphthotriazole in position 4 is described (17, 18, 14, 12). The substituent constants of these groups are obtained by alkaline hydrolysis of the corresponding phthalimide dyes. Their solvatochromism in absorption and fluorescence gives information about charge distribution in ground- and excited state.
    Notes: Die Darstellung von N-Methylphtalimiden wird beschrieben, die in 4-Stellung die Donorgruppen Pyrazol, Triazol, Benzotriazol und Naphthotriazol tragen (17, 18, 14, 12). über die alkalische Hydrolyse des Imids werden die Substituentenkonstanten der Reste bestimmt. Die Solvatochromie in Absorption und Fluoreszenz gibt Information über die Ladungsverteilung in Grund- und angeregtem Zustand.
    Additional Material: 2 Tab.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 143
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Arene(phosphane)metal Complexes, IV1). Synthesis of (6-Phosphonio-η5-cyclohexadienyl)ruthenium(II) Compounds and their Conversion into Dicationic (Benzene)ruthenium(II) Complexes[C6H6Ru(PR3)(PR3′)PR3″]2+The complexes [C6H6RuCl(PR3)PR3′]PF6 (1 - 4) and [C6H6RuCl2(PR3)] (9, 10) react with phosphanes PR3″ in the presence of NH4PF6 to give the (6-phosphonio-η5-cyclohexadienyl)ruthenium(II) compounds [(6-R3″P-η5-C6H6)Ru(PR3)(PR3′)PR3″](PF6)2 (5 - 8 11). Similarly, from [C6H6Ru(CH3CN)3](PF6)2 (12) and PMe3 the complex [(6-Me3P-η5-C6H6)Ru(PMe3)2CH3CN](PF6)2 (13) is formed. The IR and NMR spectra of 5 - 8, 11, and 13 indicate that the phosphonio group is in the exo-position at the sp3 carbon atom of the cyclohexadienyl ligand. Below - 30°C, rotation around the metal-ring bond is so hindered that rigid conformers are detected. Compounds 5 - 8 react with trifluoroacetic acid with elimination of the phosphonio group to yield the PF6 salts of the half-sandwich type complexes [C6H6Ru(PR3)(PR3′)PR3″]2+ (14 - 17).
    Notes: Die Komplexe [C6H6RuCl(PR3)PR3)]PF6 (1 - 4) und [C6H6RuCl2(PR3)] (9, 10) reagieren mit Phosphanen PR3″ in Gegenwart von NH4PF4 zu den (6-Phosphonio-η5-cyclohexadienyl)-ruthenium(II)-Verbindungen [(6-R3″P-η5-C6H6)Ru(PR3)(PR3″](PF6)2 (5 - 8, 11). Aus [C6H6Ru(CH3CN)3](PF6)2 (12) und PMe3 erhält man analog den Komplex (6-Me3P-η5-C6H6)Ru(PMe3)2CH3CN](PF6)2 (13). Die IR- und NMR-Spektren von 5 - 8, 11 und 13 weisen darauf hin, daß sich die Phosphoniogruppierung in der exo-Position am sp3-C-Atom des Cyclohexadienylliganden befindet. Unterhalb - 30°C ist die Rotation um die Metall-Ring-Bindung so stark behindert, daß starre Konformere nachweisbar sind. Die Verbindungen 5 - 8 reagieren mit Trifluoressigsäure unter Abspaltung der Phosphoniogruppe zu den PF6-Salzen der Halbsandwich-Komplexe [C6H6Ru(PR3)(PR3′)PR3″]2+ (14 - 17).
    Additional Material: 4 Tab.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 144
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Arene(phosphane)metal Complexes, VI1). Synthesis of [(RC6H5)OsI(PMe3)2]PF6 from (exo-6-RC6H6)OsI(PMe3)2: A contribution to the Mechanism of Aromatization of Substituted Cyclohexadienyl Ligands by „endo-H Abstraction“The compounds (exo-6-RC6H6)OsI(PMe3)2 (2 - 5, 7) react smoothly with [CPh3]PF6 in acetone to give the (arene)osmium(II) complexes [(RC6H5)OsI(PMe3)2]PF6 (8 - 12) in quantitative yield. The hydride elimination proceeds via two (cyclohexadienyl)hydridoosmium(IV) intermediates (13 and 14, 15, respectively) which can be prepared from 2, 5, 6 (R = CH3, n-C4H9, t-C4H9) and CF3CO2H/NH4PF6. The (cyclohexadienyl)hydrido complexes [(RC6H6)Os(H)I(PMe3)2]+ undergo an intramolecular isomerization which leads to a cation possessing a CH2 group in the six-membered ring. This cationic complex or (more probably) the neutral compound (2- or 3-RC6H6)OsI(PMe3)2 formed on deprotonation reacts with [CPh3]+ by abstraction of an exo-hydrogen atom.
    Notes: Die Verbindungen (exo-6-RC6H6)OsI(PMe3)2 (2 - 5, 7) reagieren mit [CPh3]PF6 in Aceton rasch und quantitativ zu den (Aromaten)osmium(II)-Komplexen [(RC6H5)OsI(PMe3)2]PF6 (8 - 12). Die Hydrid-Eliminierung verläuft über zwei (Cyclohexadienyl)hydridoosmium(IV)-Zwischenstufen (13 bzw. 14, 15), die aus 2, 5, 6 (R = CH3, n-C4H9, t-C4H9) und CF3CO2H/NH4PF6 synthetisiert werden können. Die (Cyclohexadienyl)hydrido-Komplexe [(RC6H6)Os(H)I(PMe3)2]+ gehen eine intramolekulare Isomerisierung ein, wobei ein Kation mit einer CH2-Gruppe im Sechsring entsteht. Dieses Komplexkation oder (wahrscheinlicher) die nach Deprotonierung erhaltene Neutralverbindung (2- bzw. 3-RC6H6)OsI(PMe3)2 reagiert mit [CPh3]+ unter Abstraktion eines exo-H-Atoms.
    Additional Material: 4 Tab.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 145
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Arene(phosphane)metal Complexes, V1). On the Addition of Carbanions to (Benzene)ruthenium(II) and -osmium(II) Complexes. The Crystal and Molecular Structure of (exo-6-n-C4H9-η5-C6H6)OsI(PMe3)2The complex [C6H6RuCl(PMe3)2]PF6 (1) reacts with methyllithium to give a mixture of products that contains (η5-C6H6CH3)RuCH3(PMe3)2 (2) as the main component. From 1 and LiC6H5/LiBr the bromide 3 is primarily formed but the final product is (η5-C6H6C6)H5RuC6H5(PMe3)2 (4). Reaction of [C6H6OsI(PMe3)2]PF6 (5) with organyllithium compounds LiR (R = CH3, C2H5, n-C3H7, n-C4H9, t-C4H9, C6H5) yields the complexes (η5-C6H6R)OsI(PMe3)2 (6 - 11). 31P NMR spectra of 6 - 11 indicate restricted rotation at low temperatures around the metal-ring axis. According to X-ray structure analysis of 9 (R = n-C4H9) the cyclohexadienyl ring possesses an envelope conformation. The n-butyl group occupies the exo-position at the sp3-C atom.
    Notes: Der Komplex [C6H6RuCl(PMe3)2]PF6 (1) reagiert mit Methyllithium zu einem Produktgemisch, welches (η5-C6H6CH3)RuCH3(PMe3)2 (2) als Hauptkomponente enthält. Aus 1 und LiC6H5/LiBr entsteht über 3 bei längeren Reaktionszeiten (η5-C6H6C6H5)RuC6H5(PMe3)2 (4). Die Umsetzung von [C6H6OsI(PMe3)2]PF6 (5) mit Organyllithium-Verbindungen LiR (R = CH3, C2H5, n-C3H7, n-C4H9, t-C4H9, C6H5 ergibt die Komplexe (η5-C6H6R)OsI(PMe3)2 (6 - 11), in denen nach den 31P-NMR-Spektren die Rotation um die Metall-Ring-Bindung bei tiefen Temperaturen stark eingeschränkt ist. Die Röntgenstrukturanalyse von 9 (R = n-C4H9) beweist die „Envelope“-Konformation des Cyclohexadienylrings. Die n-Butylgruppe befindet sich in der exo-Position am sp3-C-Atom.
    Additional Material: 1 Ill.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 146
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 117 (1984), S. 172-186 
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Radical Ions, 55. The One-Electron Oxidation of Tetrahedrane to Cyclobutadiene Radical CationTetra-tert-butyltetrahedrane, on one-electron oxidation using AlCl3 in CH2Cl2, opens to form tetra-tert-butylcyclobutadiene radical cation, which can also be generated under identical reaction conditions from tetra-tert-butylcyclobutadiene itself. The assignments of the ESR and ENDOR spectra are supported by deutero substitution of one tert-butyl group and by MNDO hypersurfaces for the thermal and for the oxidative structural changes of both C4 skeletons. The feasible formation of a valence isomeric tert-butyl(tri-tert-butylcyclopropenyl)carbene radical cation is discussed.
    Notes: Tetra-tert-butyltetrahedran öffnet sich bei Einelektronen-Oxidation mit AlCl3 in CH2Cl2 zum Tetra-tert-butylcyclobutadien-Radikalkation, das unter gleichen Reaktionsbedingungen auch aus Tetra-tert-butylcyclobutadien erzeugt werden kann. Die Zuordnungen der ESR- und ENDOR-Spektren werden durch Deutero-Substitution einer tert-Butyl-Gruppe sowie durch MNDO-Hyperflächen für die thermischen und oxidativen Strukturänderungen der beiden C4-Gerüste gestützt. Die mögliche Bildung eines valenzisomeren tert-Butyl(tri-tert-butylcyclopropenyl)carben-Radikalkations wird diskutiert.
    Additional Material: 4 Ill.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 147
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 117 (1984), S. 948-954 
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Acidic Complexones Bearing Donor-enhancing Pyridine Anchour GroupsThe synthesis, complex stability and -selectivity for alkaline earth metal ions of 2,6-pyridinebis-(methylamine)-N, N, N′, N′-tetraacetic acid (3a) and of their donor-enforced analogues 3b, c are described. The acid dissociation constants and the stability constants of the metal complexes have been measured potentiometrically at 25°C in water of constants ionic strength (μ = 0.1). The stability order is Ca 〉 Mg 〉 Sr 〉 Ba which is analogues to the selectivity of EDTA and comparable aliphatic complexones. The magnitudes of the stability constants of 3a are comparable to those of EDTA, while the donor-enforced analogues 3b, c form less stable complexes with alkaline earth metal ions.
    Notes: Synthese, Komplexstabilität und -selektivität gegenüber Erdalkalimetall-Ionen von 2,6-Pyridinbis(methylamin)-N, N, N′, N′-tetraessigsäure (3a) und ihren Donor-verstäkten Analoga 3b, c werden beschrieben. Die Bestimmung der Dissoziations- und Komplexbildungskonstanten erfolgt potentionmetrisch bei 25°C in Wasser konstanter ionaler Stärke (μ = 0.1). Die Bildungskonstanten der Metallkomplexe nehmen in der Reihenfolge Ca 〉 Mg 〉 Sr 〉 Ba ab und folgen damit der bei EDTA und vergleichbaren aliphatischen Komplexonen vorgefundenen Selektivität. 3a weist mit EDTA vergleichbare hohe Komplexbildungskonstanten auf, während die Donor-verstärkten Analoga 3b, c schwächere Erdalkalimetallkomplexe bilden.
    Additional Material: 1 Ill.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 148
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 117 (1984), S. 959-965 
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Preparation and X-Ray Structure Analysis of the Diels-Alder Adduct of 4-Phenyl-4H-1,2,4-triazole-3,5-dione with OctavaleneIn the reaction of 4-phenyl-4H-1,2,4-triazole-3,5-dione with octavalene (1) the Diels-Alder adduct 2 is formed. From its X-ray structure analysis the dihedral angle for the bicyclo[1.1.0]butane group, the 2- and 4-positions of which are spanned by four atoms, has been determined to be 122.7°. The bridging bond C1 - C3 has a length of 1.487 Å.
    Notes: Aus Octavalen (1) und 4-Phenyl-4H-1,2,4-triazol-3,5-dion bildet sich das Diels-Alder-Addukt 2. Seine Röntgenstrukturanalyse ergab für das Bicyclo[1.1.0]butan-Gerüst, dessen 2- und 4-Stellung durch vier Atome überbrückt sind, einen Interplanarwinkel von 122.7°. Die Brückenbindung C1 - C3 hat eine Länge von 1.487 Å.
    Additional Material: 3 Ill.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 149
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Condensed Ring Systems, XV. About the Reaction of α-Chloro Sulfoxides with Potassium tert-Butoxide by the Example of the Synthesis of OxapropellenesThe synthesis of dithia- 1a - 3a and oxathiapropellenes 1b - 3b is described. From 1b - 3b the α-chloro sulfoxides 4 - 6 and α-chloro sulfones 4a - 6a are prepared, or which in most cases several stereoisomeric racemates are obtained. The constitution, configuration, and conformation of the α-chloro sulfoxide 4, the main product obtained from 1b, was elucidated by X-ray structure analysis. Only in that way it was possible to deduce the constitutions and configurations of the other stereoisomeric α-chloro sulfoxides 4 - 6 and α-chloro sulfones 4a - 6a, respectively, using 13C NMR spectroscopy. By the reaction of the α-chloro sulfones 4a - 6a with potassium tert-butoxide (Ramberg-Bäcklund reaction) the corresponding oxapropellenes 7 - 9 are obtained only in low yields (〈 10%). Contrary, the α-chloro sulfoxides 4 - 6, und analogous conditions give yields of 80 - 90% (from 4, 6) and 25% (from 5).
    Notes: Es wird die Synthese der Dithia- 1a - 3a und Oxathiapropellene 1b - 3b beschrieben. Aus 1b - 3b werden die α-Chlorsulfoxide 4 - 6 und α-Chlorsulfone 4a - 6a hergestellt, von denen meist mehrere stereoisomere Racemate erhalten werden. Konstitution, Konfiguration und Konformation des Hauptprodukts der aus 1b erhaltenen α-Chlorsulfoxide 4 wurden durch Röntgenstrukturanalyse ermittelt. Erst dadurch wurde es möglich, mit Hilfe der 13C-NMR-Spektroskopie die Konstitutionen und Konfigurationen der anderen stereoisomeren α-Chlorsulfoxide 4 - 6 und α-Chlorsulfone 4a - 6a aufzuklären. Bei der Reaktion der α-Chlorsulfone 4a - 6a mit Kalium-tert-butylat (Ramberg-Bäcklund-Reaktion) erhält man die entsprechenden Oxapropellene 7 - 9 nur in geringer Ausbeute (〈 10%), während die α-Chlorsulfoxide 4 - 6 unter analogen Bedingungen Ausbeuten von 80 - 90% (aus 4, 6) und 25% (aus 5) ergeben.
    Additional Material: 1 Ill.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 150
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 117 (1984), S. 982-989 
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: On the Selectivity of the Reaction of Carbocations with NucleophilesThe problem of the selectivity of the nucleophilic attack on carbocations according to the HSAB-principle is discussed in relation to the solvolysis in ether of 7,7-bis(trifluoromethylsulfonyloxy)-norbornane (2) and 7,7-bis(trifluoromethylsulfonyloxy)-2-norbornene (4) in presence of dimethyl-magnesium, magnesium iodide and methylmagnesium iodide. The nucleophiles and carbocations are arranged according to the hard-soft-scale, so our results can be explained.
    Notes: Das Problem der Selektivität beim nucleophilen Angriff an Carbokationen wird im Rahmen des HSAB-Prinzips am Beispiel der Solvolysen in Ether von 7,7-Bis(trifluormethylsulfonyloxy)norbornan (2) und 7,7-Bis(trifluormethylsulfonyloxy)-2-norbornen (4) in Anwesenheit von Dimethylmagnesium, Magnesiumiodid und Methylmagnesiumiodid erörtert. Die Nucleophile und die als Zwischenstufen auftretenden Carbokationen werden auf der Hart-weich-Skala eingeordnet, wobei die Ergebnisse erklärt werden können.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 151
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 117 (1984), S. 1003-1012 
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Dichloropalladium(II) Complexes with α-Amino Acids, α-Amino Acid Esters, Dipeptides, and Dipeptide EstersA series of trans-dichloropalladium(II) complexes Cl2PdL2 (L = α-amino acid, α-amino acid ester, dipeptide, dipeptide esters) and cis-Cl2Pd(histidine) has been prepared and spectroscopically characterized. The X-ray structure of trans-Cl2Pd(GlyOEt)2 (3b) has been determined.
    Notes: Eine Reihe von trans-Dichloropalladium(II)-Komplexen Cl2PdL2 mit (L = α-Aminosäure, α-Aminosäureester, Dipeptid, Dipeptidester) sowie cis-Cl2Pd(Histidin) wurde dargestellt und spektroskopisch charakterisiert. Die Röntgenstruktur von trans-Cl2Pd(GlyOEt)2 (3b) wurde bestimmt.
    Additional Material: 1 Ill.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 152
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 117 (1984), S. 1436-1454 
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Evidence for a Radical Chain Mechanism for the Knabe Reaction of 1,2-Dihydro-2-methylpapaverineA free radical chain mechanism is proposed for the Knabe reaction and the accompanying elimination reaction on account of their nonintegral reaction order and of successful inhibition experiments. 3,4-Dimethoxybenzyl radicals are the chain carrying species. Battersby's synthesis of N-methylpavine (19) from 1,2-dihydro-2-methylpapaverine (9) is dependent on the presence of formic acid as radical chain inhibitor. In the presence of inhibitors 1-benzyl-1,4-dihydro-2-methyl-isoquinolinium ions like 10 are persistent species whose chemistry can now be investigated.
    Notes: Die Knabe-Reaktion von 1,2-Dihydro-2-methylpapaverin (9) und die begleitende Eliminierungsreaktion wurden durch ihre gebrochene Reaktionsordnung und durch die Möglichkeit der Inhibition als Radikalkettenreaktionen erkannt, deren kettentragendes Radikal das 3,4-Dimethoxybenzylradikal ist. Die Synthese von N-Methylpavin (19) aus 1,2-Dihydro-2-methylpapaverin (9) ist an die Anwesenheit von Ameisensäure als Inhibitor der Radikalketten gebunden. Durch Zusatz von Inhibitoren können nun Immoniumionen 10 und analoge Verbindungen stabilisiert und ihre Chemie untersucht werden.
    Additional Material: 2 Ill.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 153
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 117 (1984), S. 1455-1464 
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Azo Bridges from Azines, III. Unexpected Formation of a Compounds with Parallel C=C and N=N Bonds2)Dialdehyde 5 reacts with hydrazine at pH 〉 7 to form the trimeric azine 6Tr, at pH 〈 4, however, to yield unexpectedly 8, which contains parallel C=C and N=N bonds in close proximity. The complex reaction is clarified. 8 is characterized by structure proving reactions and its spectroscopic data.
    Notes: Der Dialdehyd 5 reagiert mit Hydrazin bei pH 〉 7 zu dem trimeren Azin 6Tr, bei pH 〈 4 unerwartet zu 8, das parallel benachbarte C=C- und N=N-Bindungen besitzt. Der komplexe Reaktionsverlauf wird aufgeklärt. 8 wird durch struktursichernde Reaktionen und spektroskopische Daten charakterisiert.
    Additional Material: 1 Ill.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 154
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 117 (1984), S. 1465-1475 
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Azo Bridges from Azines, IV1). Intramolecular [2 + 2] Photocycloaddition of Parallel C=C and N=N BondsThe parallel C=C and N=N bonds in the rigid molecules 1 - 10 photocyclize nearly quantitatively, forming 1,2-diazetidines 11 - 20. Their structure is confirmed by spectroscopic methods and for 13 by X-ray analysis. Radiation induced denitrogenation, the normal reaction for similar compounds without neighbouring C=C bonds, is suppressed even with the sensitive derivatives of 2,3-diazabicyclo[2.2.1]heptene. Photocyclization of 6, carrying two neighbouring C=C bonds, includes only the norbornene bond.
    Notes: In den starren Molekülen 1 - 10 reagieren die benachbarten parallelen C=C- und N=N-Bindungen nahezu quantitativ unter Photocyclisierung zu den 1,2-Diazetidinen 11 - 20, deren Struktur spektroskopisch und für 13 durch Kristallstrukturanalyse bewiesen wird. Die in Abwesenheit der C=C-Bindung beobachtete Photo-Denitrogenierung unterbleibt selbst bei den empfindlichen Derivaten des 2,3-Diazabicyclo[2.2.1]heptens. Photocyclisierung von 6 mit zwei zur N=N-Bindung benachbarten C=C-Bindungen tritt nur mit der Norbornendoppelbindung ein.
    Additional Material: 5 Tab.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 155
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 117 (1984), S. 1497-1512 
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Amino Acids, 21,2). N-Acetyl α,β-Didehydro α-Amino Acid Esters from α-Azidocarboxylic Acid Esters and Acetic Anhydride by Nitrogen Elimination with Rhenium Catalystsα-Azidocarboxylic acid esters 2 react with acetic anhydride in presence of catalytic amounts of rhenium heptasulfide and - if necessary - by addition of hydrochloric acid to give N-acetyl 3 or/and N,N-diacetyl-α,β-didehydro-α-amino acids esters 4 in very good yields. Exclusively monoacetylated products 3 are formed if water ist added before work up.
    Notes: Beim Erwärmen von α-Azidocarbonsäureestern 2 in Acetanhydrid/Essigsäure in Gegenwart katalytischer Mengen Rheniumheptasulfid und gegebenenfalls unter Zugabe von Chlorwasserstoff entstehen in sehr guten Ausbeuten N-Acetyl- 3 und/oder N,N-Diacetyl-α-β-didehydro-α-amino-säureester 4. Durch Zugabe von Wasser vor der Aufarbeitung erfolgt partielle Deacetylierung unter ausschließlicher Bildung der N-Monoacetylverbindungen 3.
    Additional Material: 7 Tab.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 156
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Amino Acids, 31). N-Acetylated α-β-Didehydro α-Amino Acid Derivatives by Nitrogen Elimination from α-Azido-carboxylic Acid Amides and α-Azido-ω-aminocarboxylic Acid Lactams with Rhenium Catalystsα-Azidocarboxylic acid amides 2 and α-azido-ω-aminocarboxylic acid lactams 6, respectively, react with acetic anhydride in the presence of rhenium catalysts by nitrogen eliminations to give N-acetyl- 7 and N,N-diacetyl-α,β-didehydro-α-amino acid amides 8, α-acetylamino- 11 and α-diacetylamino-α,β-didehydro-ω-aminocarboxylic acid lactams 12, respectively. Reactions of the educts 6c, d - with a ring size 7 or 8 - additionally lead to the oxazoloazepine 14c and the oxazoloazocine 14d, respectively.
    Notes: Bei der Umsetzung von α-Azidocarbonsäureamiden 2 mit Acetanhydrid in Gegenwart von Rheniumkatalysatoren entstehen unter Stickstoffabspaltung N-Acetyl- 7 und N,N-Diacetyl-α,β-didehydro-α-aminosäureamide 8, bei der von α-Azido-ω-aminocarbonsäurelactamen 6 α-Acetyl-amino- 11 und α-Diacetylamino-α,β-didehydro-ω-aminocarbonsäurelactamen 12, wobei sich aus den Verbindungen 6c, d, mit der Ringgliederzahl 7 bzw. 8 außerdem noch das Oxazoloazepin 14c bzw. das Oxazoloazocin 14d bilden.
    Additional Material: 3 Tab.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 157
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Contributions to the Chemistry of Phosphorus, 131. Synthesis and Properties of the Methylenediphosphiranes (t-BuP)2)C = CR2 (R = H, Me, 4-ClC6H4)The first methylenediphosphiranes (diphosphamethylenecyclopropanes) (t-BuP)2C = CH2 (1), (t-BuP)2C = CMe2 (2), and (t-BuP)2C = C(4-ClC6H4)2 (3) were synthesized by [2 + 1] cyclocondensation of K(t-Bu)P - P(t-Bu)K with the corresponding 1,1-dichloroolefins. The homocyclophosphanes (t-BuP)n (n = 4,3) and in the case of 1 mainly H(t-Bu)P - P(t-Bu)H are formed as by-products. The three-membered heterocycles 2 and 3 could be purely isolated as surprisingly stable compounds. According to an X-ray single-crystal analysis 3 possesses approximately C2 symmetry and exhibits one of the smallest bonding angles ψ (P - P - C) = 52.4° on a phosphorus atom experimentally proved so far. Along [100] there are canals filled with disordered n-pentane molecules.
    Notes: Die ersten Methylendiphosphirane (Diphosphamethylencyclopropane) (t-BuP)2C = CH2 (1), (t-BuP)2C = CMe2 (2) und (t-BuP)2C = C(4-ClC6H4)2 (3) wurden durch [2 + 1]-Cyclokondensation von K(t-Bu)P - P(t-Bu)K mit den entsprechenden 1,1-Dichlorolefinen synthetisiert. Als Nebenprodukte entstehen die Homocyclophosphane (t-BuP)n (n = 4,3) und im Fall von 1 vor allem H(t-Bu)P - P(t-Bu)H. Die Dreiringheterocyclen 2 und 3 konnten als thermisch überraschend beständige Verbindungen in reiner Form isoliert werden. 3 besitzt nach der Röntgenstrukturanalyse annähernd die Symmetrie C2 und enthält mit ψ (P - P - C) = 52.4° einen der kleinsten experimentell gesicherten Bindungswinkel am Phosphor. Längs [100] liegen fehlgeordnet mit n-Pentan gefüllte Kanäle vor.
    Additional Material: 2 Ill.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 158
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 117 (1984), S. 1523-1541 
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Aminierung, III. Trimethylsilanol als austretende Gruppe, V. Silylierung-Aminierung von Hydroxy-N-heterocyclenDurch Silylierung-Aminierung lassen sich Hydroxy-N-heterocyclen (z. B. 18, 21, 26 u. a.) bequem in einer Einstufen-Eintopfreaktion aminieren (→ 20, 23 - 25 etc.). Aromatische Hydroxy-N-heterocyclen werden durch Silylierung in aktivierte und lipophile Zwischenprodukte vom Typ 3, 8 umgewandelt, die sich in situ mit Ammoniak, primären oder sekundären Aminen zu den entsprechenden mono-, bis- und tris-aminierten Produkten (5, 10) umsetzen. Die Additions-Eliminierungsreaktion von Aminen an O-silylierte Heterocyclen ist Lewissäure-katalysiert und verläuft gewöhnlich in hohen Ausbeuten, falls die austretende Gruppe Trimethylsilanol in situ durch überschüssiges Silylierungsmittel in Hexamethyldisiloxan umgewandelt wird. Anwendungsbreite und Grenzen dieser einfachen Methode werden diskutiert.
    Notes: Hydroxy N-heterocycles such as 18, 21, 26, and others are efficiently aminated in a one-step/one-pot procedure by silylation-amination to give 20, 23 - 25 etc. Silylation converts aromatic hydroxy N-heterocycles into activated and lipophilic intermediates of type 3, 8 which react in situ with ammonia, primary or secondary amines to form the corresponding mono-, bis- or tris-aminated products (5, 10). This addition-elimination of amines to O-silylated heterocycles in Lewis acid-catalyzed and proceeds usually in high yields if the leaving group trimethylsilanol is converted in situ by excess silylated agent into hexamethyldisiloxane. Scope and limitations of this simple procedure are discussed.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 159
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 117 (1984), S. 1572-1582 
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Benzonitrile as a 6-Electron Donor Ligand: The Clusters Fe3(CO)9(μ3(η2)-NCC6H5) and Fe4(CO)12(μ4(η2)-NCC6H5)The reaction of Fe3(CO)12 with benzonitrile in the presence of hydrogen leads to the benzonitrile complexes Fe3(CO)9(μ3(η2)-NCC6H5) (1a) and Fe4(CO)12(μ4(η2)-NCC6H5) (2). Their structures were determined crystallographically. The benzonitrile ligand is coordinated to the iron atoms formally via on „s̰-bond“ and two „π-bonds“ in 1a, and via three s̰-bonds and one π-bond in 2.
    Notes: Die Reaktion von Fe3(CO)12 mit Benzonitril in Anwesenheit von Wasserstoff führt zu den beiden Benzonitril-Komplexen Fe3(CO)9(μ3(μ2)-NCC6H5) (1a) und Fe4(CO)12(μ4(η2)-NCC6H5) (2). Ihre Strukturen wurden kristallographisch aufgeklärt. Der Benzonitril-Ligand ist in 1a formal über eine „s̰-Bindung“ und zwei „π-Bindungen“, in 2 über drei s̰-Bindungen und eine π-Bindung an die Eisenatome koordiniert.
    Additional Material: 2 Ill.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 160
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Spin-Spin Coupling Constants by Platinium-195 as Criteria for a Configuration Determination in Platinum Organic CompoundsThe platinum organic compounds [Pt(η4-1,5-cyclooctadiene)(XC6H4)2] and cis-[Pt(P(n-Bu)3)2-(XC6H4)2] (X = H, 4-CH3, 4-(CH3)3C, 4-(CH3)2N, 3-F, 4-F, 4-CH3O, 4-CF3; 3a - 4, cis-4a - h) as well as trans-[Pt(P(n-Bu)3)2(4-CH3OC6H4)2] (trans-4g) and trans-[Pt(P(n-Bu)3)2(4-CF3C6H4)2] (trans-4h) have been studied by 31P-, 13C-, and 1H NMR spectroscopy. The coupling constants 1J[195Pt, 31P], nJ[195Pt, 13C], nJ[195Pt, H], and 2J[31P, 13C] show a clear correlation to the ligand configuration at the dsp2-hybridized platinum and can therefore be used as basis for configuration determination.
    Notes: Die platin-organischen Verbindungen [Pt(η4-1,5-cyclooctadien)(XC6H4)2] und cis-[Pt(P(n-Bu)3)2-(XC6H4)] (X = H, 4-CH3, 4-(CH3)3C, 4-(CH3)2N, 3-F, 4-F, 4-CH3O, 4-CF3; 3a - h, cis-4a - h) sowie trans-[Pt(P(n-Bu)3)2(4-CH3OC6H4)2] (trans-4g) und trans-[Pt(P(n-Bu)3)2(4-CF3C6H4)2] (trans-4h) wurden 31P-, 13C- und 1-NMR-spektroskopisch untersucht. Die Kopplungskonstanten 1J[195Pt, 31P], nJ[195Pt, 13C], nJ[195Pt, H] und 2J[31P, 13C] zeigen eine eindeutige Abhängigkeit von der Konfiguration der Liganden am dsp2-hybridisierten Platin; sie können daher zur sicheren Konfigurations-Bestimmung verwendet werden.
    Additional Material: 8 Tab.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 161
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 117 (1984), S. 1597-1605 
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: On the Structure of N-Methylenecarboxamides: X-Ray Data, Spectroscopy, and Quantum Mechanical CalculationsN-(Diphenylmethylene)acetamide (1) has been studied by X-ray crystallography as an example for the polyfunctional, highly reactive N-methyleneamides. The dihedral angle (C = N - C = O = 73°) and the bond lengths indicate that there is only little interaction between the C = O and the C = N groups. Extensive ab initio 3-21G calculations for the parent molecule H2C = N - CH = O (2) predict a C - N rotational barrier of ca. 4 kcal/mol with a cisoid form (C = N - C = O = 23°) as the most stable structure. MNDO data as well as spectroscopic properties (IR, 13C NMR) suggest high molecular flexibility due to the many electronic interactions possible for the nitrogen atom.
    Notes: Als Beispiel für die polyfunktionellen N-Methylencarbonsäureamide wurde N-(Diphenylmethylen)acetamid (1) röntgenographisch untersucht. C = N - C = O-Torsionswinkel (73°) und Bindungslängen deuten auf nur geringe Wechselwirkungen zwischen C = O- und C = N-Molekülteil. Ausführliche ab initio-3-21G-Berechnungen am Grundsystem H2C = N - CH = O (2) sagen eine C - N-Rotationsbarriere von ca. 4 kcal/mol voraus, wobei als stabilste Struktur eine cisoide Form (C = N - C = O-Winkel = 23°) gefunden wurde. MNDO-Daten und spektroskopische Untersuchungen (IR, 13C-NMR) deuten ebenfalls auf hohe molekulare Beweglichkeit, die vor allem durch die vielfältigen elektronischen Wechselwirkungsmöglichkeiten des Stickstoffatoms verursacht wird.
    Additional Material: 3 Ill.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 162
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 117 (1984), S. 1659-1670 
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Reduction of β-Lactams, I. Reduction of 3,3,3′,3′-Tetramethyl[1,1′-biazetidine]-2,2′-dione with Complex HydridesReduction of the title compound 7 with lithium aluminium hydride leads to four products 8 to 11 in yields depending on the reaction conditions. Compounds 8 to 10 are also obtained from the bicyclic hydrazide 12, isomeric with 7. Therefore, the reduction of 7 and 12 is likely to proceed in part via common intermediates. A reaction scheme is proposed to account for the generation of the products. With other hydride reagents complex reaction mixtures are obtained from 7. The reduction of 7 to 3,3,3′,3′-tetramethyl-1,1′-biazetidine (13) failed.
    Notes: Die Reduktion der Titelverbindung 7 mit Lithiumaluminiumhydrid liefert die vier Produkte 8 - 11 in von den Reaktionsbedingungen abhängigen Mengenverhältnissen. Da die Verbindungen 8 - 10 auch aus dem mit 7 isomeren bicyclischen Hydrazid 12 erhalten werden, muß die Reduktion von 7 und 12 z. T. einheitlich ablaufen. Hierfür wird ein Reaktionsschema vorgeschlagen. Mit anderen Hydridübertragungsreagenizen entstehen aus 7 komplexe Produktgemische. Die Reduktion von 7 zu 3,3,3′,3′-Tetramethyl-1,1′-biazetidin (13) gelang nicht.
    Additional Material: 1 Ill.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 163
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 117 (1984), S. 565-574 
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Synthesis of (Trimethylstannyl)adamantane DerivativesReaction of brominated adamantane compounds with (trimethylstannyl)lithium afforded a series of (trimethylstannyl)adamantane derivatives. Additionally, we found products from fragmentation and reduction reactions which allowed conclusions concerning the mechanisms. Surprisingly high stereoselectivities were observed in most instances. By Wurtz synthesis we obtained 2-adamantyltriphenylstannane.
    Notes: Die Umsetzung bromierter Adamantanverbindungen mit (Trimethylstannyl)lithium lieferte eine Reihe von (Trimethylstannyl)adamantan-Derivaten. Wir fanden zusätzlich Fragmentierungs- und Reduktionsprodukte, die Rückschlüsse auf den Mechanismus zuließen. Überraschend ist die hohe Stereoselektivität der meisten Reaktionen. Durch Wurtz-Synthese wurde auch 2-Adamantyltriphenylstannan erhalten.
    Additional Material: 1 Ill.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 164
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 117 (1984), S. 575-584 
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Influence of Substituents on the Valence-tautomeric Equilibrium of 4,8-Substituted HomotropilidenesThe valence-tautomeric equilibrium of 4,8-substituted homotropilidenes 2 - 4 is governed by electronic (preference of a substituent for attachment to a cyclopropyl or an aliphatic carbon atom) and steric factors. The conformational change chair → boat, which precedes the Cope rearrangement of a homotropilidene, cannot take place when both endo-8- and cis-4-substituents are present.
    Notes: Das Valenzgleichgewicht 4,8-substituierter Homotropilidene 2 - 4 wird durch elektronische (Präferenz eines Substituenten für Cyclopropyl- oder aliphatische Verknüpfung) und sterische Faktoren bestimmt. Die der Cope-Umlagerung vorgeschaltete Konformationsänderung Sessel → Boot wird verhindert, wenn das Homotropiliden sowohl in endo-8- wie in cis-4-Stellung substituiert ist.
    Additional Material: 1 Tab.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 165
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Heterocyclic β-Enamino Esters, 311). Novel 6:7-, 6:8, and 5:6:7-Combinations of Heterocondensed Pyrimidines from Iminophosphoranes of Heterocyclic β-Enamino Esters. - Stable Heterocyclic YlidesWith acetylenic esters the (5-azolylimino)triphenylphosphoranes 10a - d do not show any cyclo-addition tendency, while the (2-thienylimino)triphenylphosphoranes 8a, b yield the stable ylids 13a, b. By treatment with phenyl isocyanate the iminophosphoranes 16a - m, 17, and 18a, b afford the carbodiimides 19a - m, 20, and 21a, b; however, 10b - d give the O-ethylisoureas 24b - d. 19a, b, e, f, h are transformed in aqueous ethanol into 6:7-bicycles, namely into oxepino[2,3-d]pyrimidines 25a, b, e, f, h. With isopropylamine the 2-isopropylamino-6:7-bicycles 31a - c, e - h are formed analogously, while in the case of thiocin 21a the 6:8-bicycle 34 is obtained. The salts 33f, g are formed by treating 19f, g or 25f with aqueous diethylamine. Accordingly, 2-aminoethanol, 3-aminopropanol, and ethylenediamine react with 19a, b, f, l to afford the 2-hydroxy- and 2-aminoalkyl-6:7-bicycles 36a - f; by treatment with hydrazine the 2-hydrazinooxepino- and -thiepino[2,3-d]pyrimidines 38a - h and 39 are obtained, which are converted with functional C1-units into 5:6:7-tricycles 43a - d, 45'a, b.
    Notes: Die (5-Azolylimino)triphenylphosphorane 10a - d zeigen mit Acetylendicarbonsäureestern keine Tendenz zur Cycloaddition, während die (2-Thienylimino)triphenylphosphorane 8a, b, zu den stabilen Yliden 13a, b reagieren. Mit Phenylisocyanat ergeben die Iminophosphorane 16a - m, 17 und 18a, b die Carbodiimide 19a - m, 20 und 21a, b; 10b - d liefern statt dessen die O-Ethylisoharnstoffe 24b - d. In wäßrigem Ethanol werden 19a, b, e, f, h in 6:7-Bicyclen, nämlich in die Oxepino[2,3-d]pyrimidine 25a, b, e, f, h umgewandelt. Mit Isopropylamin bilden sich die 2-Isopropylamino-6:7-Bicyclen 31a - c, e - h und im Fall des Thiocins 21a der 6:8-Bicyclus 34. Die Salze 33f, g entstehen durch Einwirkung von wäßrigem Diethylamin auf 19f, g bzw. auf 25f. 2-Aminoethanol, 3-Aminopropanol und Ethylendiamin ergeben mit 19a, b, f. l analog die 2-Hydroxy- und 2-Aminoalkyl-6:7-Bicyclen 36a - f; mit Hydrazin werden die 2-Hydrazinooxepino- und -thiepino[2,3-d]pyrimidine 38a - h und 39 erhalten, die mit funktionellen C1-Bausteinen zu den 5:6:7-Tricyclen 43a - d, 45'a, b führen.
    Additional Material: 24 Tab.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 166
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 117 (1984), S. 682-693 
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Addition of Aldehydes to Activated Double Bonds, XXXIV1). Addition of Aldehydes to Cyclic α-Methylene KetonesThe thiazolium salt-catalyzed addition of aldehydes to the cyclic α-methylene ketones 3, 4, 7, 8, 48, and 49 leads to γ-diketones 9 - 22, 50 - 53; some of them were converted into unsaturated ketones 23 - 28, pyrroles 29 - 34, 37 - 43, and furans 35, 36, 44 - 46. The α-methylene ketones were synthesized by retro Diels-Alder reaction of the corresponding norbornene compounds 1, 2, 5, 6, 47.
    Notes: Die Thiazoliumsalz-katalysierte Addition von Aldehyden an die cyclischen α-Methylenketone 3, 4, 7, 8, 48 und 49 führt zu γ-Diketonen 9 - 22, 50 - 53, aus denen einige ungesättigte Ketone 23 - 28, Pyrrol- 29 - 34, 37 - 43 und Furanderivate 35, 36, 44 - 46 synthetisiert wurden. Die Darstellung der α-Methylenketone erfolgte durch Retrospaltung entsprechender Norbornenderivate 1, 2, 5, 6 und 47.
    Additional Material: 7 Tab.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 167
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 117 (1984), S. 694-701 
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Diazadiene als Steuerliganden in der Katalyse, 51). Synthese chiraler Diazadiene R* - N = CR' - CR' = N - R*Die im Prinzip einfache Kondensationsreaktion von Glyoxal (als Hydrat) und 2,3-Butandion mit primären Aminen führt leider bei aliphatischen Aminen mit tertiärem bzw. sekundärem α-Kohlenstoff oftmals zu unerwünschten Additionsprodukten. Unter speziellen Synthesebedingungen können mit (R)-1-Phenylethylamin (1) und (1S,2S,3S,5R)-3-(Aminomethyl)pinan die gewünschten Diimine (Diazadiene (dad): R* - N = CR' - CR' = N - R*, R' = H, CH3) 4, 6 - 8 erhalten werden. Aus (S)-2-Amino-1-butanol (3) werden je nach Dion-Komponente ein Morpholinomorpholin 9 bzw. ein Bioxazolidin 10 gebildet, die von elektronenreichen Metallen in ihrer isomeren Form als Diazadiene gebunden werden ((dad)Mo(CO)4 11 und 12). Die offenkettige dad-Form ist durch O-Silylierung (14, 15) stabilisierbar. Die (dad)Eisen(0)-katalysierte Dimerisierung von Butadien zu 4-Vinyl-1-cyclohexen mit diesen dad-Liganden ergibt Enantiomerenüberschüsse e.e. bis zu 16%.
    Notes: The condensation of glyoxal (as hydrate) or 2,3-butanedione with primary amines is, in principle, a simple reaction. Unfortunately, aliphatic amines with secondary or tertiary α-carbons often give unwanted addition products. Under special reaction conditions the desired diimines (diazadienes (dad): R* - N = CR' - CR' = N - R*, R' = H, CH3) 4, and 6 - 8 are obtained from (R-1-phenyl-ethylamine (1) and (1S,2S,3S,5R)-3-(aminomethyl)pinane (2). Depending on the dione, a morpholinomorpholine 9 and a bioxazolidine 10 are formed from (S)-2-amino-1-butanol (3), which are bound by electron-rich metals in their isomeric dad form ((dad)Mo(CO)4 11 and 12). The acyclic dad structure is stabilized by O-silylation (14, 15). The (dad)iron(0) catalyzed dimerization of butadiene with these controlling ligands to 4-vinyl-1-cyclohexene occurs with an enantiomeric excess up to 16%.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 168
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Application of High-Resolution Solid State NMR Spectroscopy for the Determination of the Ring-Chain TautomerismThe structure of the benzaldehyde derivatives 1 and 2 showing ring-chain tautomerism was investigated by NMR spectroscopy in the solid state and in solution. Difficulties in preparing single crystals, low solubility, and the presence of solvent in the crystal prevent an X-ray analysis and other spectroscopic methods. The structural problem was solved by C-13 CP-MAS NMR spectroscopy. 2-[2-(Methylamino)ethyl]-3-nitrobenzaldoxime (1) exists in the chain form in the crystal but is in equilibrium with the cyclic isomer in solution. Two different types of crystals were obtained from the aminoethenylbenzaldehyde derivative 2, one of them containing the chain the other the cyclic form of 2. Signal assignments in the solid state result from comparison with the spectra in solution, which have been partially assigned by 2D 1H 13C NMR shift correlation.
    Notes: Die Struktur der Benzaldehyd-Derivate 1 und 2, die Ring-Ketten-Tautomerie zeigen, wird durch NMR-Spektroskopie im festen und gelösten Zustand untersucht. Schwierigkeiten beim Züchten von Einkristallen sowie die Schwerlöslichkeit bzw. die Anwesenheit von Kristallösungsmittel verhinderten die Anwendung der Röntgenstrukturanalyse und anderer spektroskopischer Methoden. Mit Hilfe von C-13-CP-MAS-NMR-Spektren wird das Strukturproblem lösbar. In 2-[2-(Methyl-amino)ethyl]-3-nitrobenzaldoxim (1) liegt im Kristall die offene Form vor, die in Lösung mit dem cyclischen Tautomeren 1b im Gleichgewicht steht. Vom Aminoethenylbenzaldehyd-Derivat 2 lassen sich zwei verschiedene Kristalle gewinnen, in denen alternativ die offene und die cyclische Struktur vorliegt. Zur Signalzuordnung werden die Festkörper-NMR-Spektren mit den z. T. durch 2D-1H-13C-NMR-Verschiebungskorrelation zugeordneten C-13-Spektren verglichen.
    Additional Material: 2 Ill.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 169
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 117 (1984), S. 710-724 
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Asymmetric Catalyses, 121). New Optically Active P,N Ligands and Their Use in Rh-Catalyzed Asymmetric Hydrogenation and HydrosilylationNew P,N-ligands 2, 4 and 5 were prepared by Schiff base condensation of (2-formylphenyl)diphenyl- and tris(2-formylphenyl)phosphane with (R)-(+)-1-phenylethylamine and ethylenediamine. (R)-(+)-aminphos (6) was obtained by hydrogenation of the C = N bond in (R)-(+)-iminphos (2). The new imine ligands form stable chelate complexes. The pseudotetrahedral CpFe(CO)[R)-(+)-iminphos]PF6 was separated into the diastereoisomes with respect to the Fe configuration. The square planar Rh[(R)-(+)-iminphos]2X is obtained as a cis/trans mixture. The isolated Rh complexes and the combinations [Rh(COD)Cl]2/2, 4, and 6, respectively, were used as catalysts for the homogeneous hydrogenation of (Z)-α-(acetylamino)cinnamic acid and for the hydrosilylation of acetophenone with diphenysilane. The optical yield of 1-phenyl-ethanol, the product of hydrolysis of the hydrosilylation, increases with increasing ligand excess, decreasing catalyst concentration, and decreasing temperature.
    Notes: Neue P,N-Liganden 2, 4 und 5 wurden durch Schiffbasenkondensation von (2-Formylphenyl)diphenyl- und Tris(2-formylphenyl)phosphan mit (R)-(+)-1-Phenylethylamin und Ethylendiamin dargestellt. (R)-(+)-aminphos (6) wurde durch Hydrierung der C = N-Bindung in (R)-(+)-iminphos (2) erhalten. Die neuen Imin-Liganden bilden stabile Chelatkomplexe. Das pseudotetraedrische CpFe(CO)[(R)-(+)-iminphos]PF6 wurde in die Diastereomeren bezüglich der Fe-Konfiguration getrennt. Das quadratisch-planare Rh[(R)-(+)-iminphos]2X fällt als cis/trans-Gemisch an. Die isolierten Rh-Komplexe und die Kombinationen [Rh(COD)Cl]2/ 2, 4 bzw. 6 wurden als Katalysatoren für die homogene Hydrierung von (Z)-α-(Acetylamino)zimtsäure und für die Hydrosilylierung von Acetophenon mit Diphenylsilan eingesetzt. Die optische Ausbeute an 1-Phenylethanol, dem Hydrolyseprodukt der Hydrosilylierung, steigt mit zunehmendem Ligandenüberschuß, mit abnehmender Katalysatorkonzentration und mit abnehmender Temperatur.
    Additional Material: 2 Ill.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 170
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 117 (1984), S. 3021-3033 
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Synthesis and Solvolysis of (Z)/(E)-1-Methyl-2-[2-(1-propyn-1-yl)phenyl]vinyl Triflate and 1-Methylene-2-[2-(1-propyn-1-yl)phenyl]ethyl TriflateThe synthesis and solvolysis of the triflates (Z)/(E)-8 and 20 in various solvents are described. The (E)-triflate 8 reacts in trifluoroethanol by rearrangement via the intermediate naphthyl cation 9 to give the naphthyl ether 22 and the naphthyl triflate 24. The identification of 1-bromo-2,3-dimethylnaphthalene (26) after addition of bromide ions to the solvolysis confirms 9 as a reactive intermediate. The (Z)-triflate 8 solvolyses preferably to the elimination product 28, the formation of [(3-methyl-2-naphthyl)methyl] (trifluoroethyl) ether (23), however, can not be explained via the cation 9 as an intermediate. The solvolysis of the triflate 20 leads also to the rearranged products 22 and 23.
    Notes: Die Synthese und Solvolyse der Triflate (Z)/(E)-8 und 20 in verschiedenen Lösungsmitteln wird beschrieben. Das (E)-Triflat 8 reagiert in Trifluorethanol bevorzugt unter Umlagerung über das intermediäre Naphthylkation 9 zum Naphthylether 22 und zum Naphthyltriflat 24. Der Nachweis von 1-Brom-2,3-dimethylnaphthalin (26) nach Bromidionenzusatz zur Solvolyse bestätigt 9 als reaktive Zwischenstufe. Das (Z)-Triflat 8 solvolysiert bevorzugt zum Eliminierungsprodukt 28, die Bildung des [(3-Methyl-2-naphthyl)methyl]-(trifluorethyl)-ethers (23) kann jedoch nicht über das Kation 9 als Zwischenstufe erklärt werden. Die Solvolyse des Triflates 20 führt ebenfalls zu den Umlagerungsprodukten 22 und 23.
    Additional Material: 1 Tab.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 171
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 117 (1984), S. 3160-3164 
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Measurement of Absolute Rates of Radical Additions to Alkenes by the “Mercury Method”Using the 5-hexenyl radical (2) as “radical clock” the rates of radical additions to methyl acrylate (5a) and acrylonitrile (5b) are measured by the “mercury method” (Table 1). Alkyl radicals are trapped by the alkylmercury hydride 1 with rate constants of at least 107 1 · mol-1 · s-1.
    Additional Material: 2 Tab.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 172
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 117 (1984) 
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 173
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 117 (1984), S. 3175-3182 
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Radical Chain Reactions with Maleic Anhydrides  -  Contrathermodynamic StereoselectivityThe reactions of cyclohexylmercuric chloride with NaBH4 and alkenes 1a-g yield 60-84% of products 3, 4 and 6 in a radical chain process (table 1). Caused by steric effects of substituents Z at least 97% of the radical attack occurs at the unsubstituted carbon atom of maleic anhydrides 1c-g. Only fluoromaleic anhydride 1b is attacked by cyclohexyl radicals predominantly at the substituted carbon atom, because fluorine is a tiny, electron releasing substituent. Radicals 2 are trapped predominantly from the anti-direction by the H-donor (figure 1), yielding cis-compounds 3 as main products. This „contrathermodynamic“ stereoselectivity ranges between 2.3 and 19 (table 1).
    Notes: Die Reaktion von Cyclohexylquecksilberchlorid mit NaBH4 und den Alkenen 1a-g liefert in einer Radikalkettenreaktion die Produkte 3, 4 und 6 in 60- bis 84proz. Ausbeuten (s. Tab. 1). Wegen der sterischen Effekte der Substituenten Z erfolgt der Angriff der Radikale zu mindestens 97% am unsubstituierten C-Atom der Maleinsäureanhydride 1c-g. Allein das Fluormaleinsäureanhydrid 1b wird bevorzugt am substituierten C-Atom durch Cyclohexyl-Radikale angegriffen. Die Ursache für diese umgekehrte Regioselektivität liegt in der geringen Raumerfüllung und dem elektronenspendenden Effekt des Fluoratoms. Die H-Übertragung auf die Radikale 2 erfolgt überwiegend von der anti-Seite (s. Abb. 1), so daß die thermodynamisch instabileren cis-Verbindungen 3 als Hauptprodukte entstehen. Diese „kontrathermodynamische“ Stereoselektivität liegt zwischen 2.3 und 19 (s. Tab. 1).
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 174
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 117 (1984), S. 1241-1245 
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Reactive Platinum Complexes with α-Amino Acid Derivatives and their 31P- and 15N Nuclear Magnetic Resonance SpectraThe α-amino acidate chelate complexes (n-Bu3P)(Cl)⊓PtNH2CH(R)COO (1a - c) (R = H, CH3, CHMe2) react with thionyl chloride, phosphorus pentachloride, or acetyl chloride by cleavage of the chelate ring to give complexes with α-amino acyl chloride or acetic glycine anhydride as ligands: (n-Bu3P)Cl2Pt(NH2CH2COCl) (2), (n-Bu3P)Cl4Pt(NH2CH(CHMe2)COCl) (6), (n-Bu3P)-Cl2Pt(NH2CH2CO(O)OCCH3) (4). Using 15N enriched amino acids, the IR, 15N and 31P NMR spectra indicate cis orientation of phosphane and amino groups in all these complexes.
    Additional Material: 3 Tab.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 175
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 117 (1984), S. 1246-1249 
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Syntheses with Alkenediazonium Salts, III. ω,ω′-Di-1H-1,2,3-triazolylalkanes from Ethenediazonium Hexachloroantimonates and ω,ω′-DiaminoalkanesReaction of the ethenediazonium hexachloroantimonates 2 with ω,ω′-diaminoalkanes 3 leads to ω,ω′-di-1H-1,2,3-triazolylalkanes 5.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 176
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 117 (1984), S. 1222-1234 
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Contributions to the Chemistry of Boron, 1351). Addition Compounds of 1,3,2-Diazaborolidines with Aluminium and Gallium Halides1,3-Dimethyl-1,3,2-diazaborolidines 3 - 6 add aluminium and gallium halides, respectively, in a 1 : 1 molar ratio. The ligand is monodentate in these coordination compounds (3a - e, 4a, 5a, b, 6a). Addition occurs at one of the ring nitrogen atoms irrespective of the B-substituent. A consequence of this coordination is a long BN bond to the chiral tetracoordinated nitrogen atom as well as a considerable shortening of the BN bond involving the tricoordinate ring nitrogen. In addition, the almost planar five-membered ring adopts the envelope conformation as shown by an X-ray structure analysis of 5a. In contrast, the 2-(dimethylamino)diazaborolidine 7 yields unstable 1 : 1 besides stable 1 : 2 adducts 8. In these the Lewis acid is also coordinated to the ring nitrogen atoms only.
    Notes: Die 1,3-Dimethyl-1,3,2-diazaborolidine 3 - 6 addieren Aluminium- oder Galliumhalogenide im Molverhältnis 1 : 1 zu Koordinationsverbindungen 3a - e, 4a, 5a, b, 6a, in denen der Ligand einzähnig ist. Die Anlagerung erfolgt unabhängig vom B-Substituenten an einem Ringstickstoff-Atom. Folge dieser Koordination ist die Ausbildung einer langen BN-Bindung zum chiralen tetra-koordinierten Ring-Stickstoff, eine erhebliche Verkürzung der BN-Bindung zum dreifach koordinierten endocyclischen Stickstoffatom und der Übergang des nahezu planaren Fünfrings in die „envelope“-Konformation, wie die Röntgenstrukturanalyse von 5a belegt. Im Gegensatz dazu liefert das 2-(Dimethylamino)diazaborolidin 7 mit AlX3 und GaX3 instabile 1 : 1- und stabile 1 : 2-Addukte 8. In diesen ist die Lewis-Säure nur an den Ringstickstoff-Atomen koordiniert.
    Additional Material: 3 Ill.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 177
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 117 (1984), S. 1250-1254 
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: A Simple Synthesis of Primary Amines via their N,N-Bis(trimethylsilyl) DerivativesPrimary halogen compounds 1 or the corresponding tosylates react with sodium bis(trimethylsilyl)amide (2) in hexamethyldisilazine to form N,N-bis(trimethylsilyl)amines 3, which are converted into the amine hydrochlorides 5 by treatment with aqueous HCl.
    Additional Material: 1 Tab.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 178
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 117 (1984), S. 1255-1258 
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Dibenz[a,j]anthracen durch Photocyclodehydrierung von 9,10-Dihydro-2-styrylphenanthrenWährend aus 2-Styrylphenanthren (1) durch Photocyclodehydrierung Benzo[c]chrysen (2) entsteht, läßt sich unter Ausnutzung der „ΣF*-Regel“5) aus 9,10-Dihydro-2-styrylphenanthren (4) durch Photocyclodehydrierung zu 6 und anschließende Dehydrierung Dibenz[a,j]anthracen (3) erhalten.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 179
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 117 (1984), S. 1259-1261 
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: A Simple Synthesis of 5-Cyano-2-pyridinecarboxylic Acid and its AmideThe title compounds 3 and 2 (X = CN) are prepared in good yields by regioselective carbamoylation of 3-cyanopyridine in a Minisci reaction and by consecutive amide hydrolysis with amyl nitrite in HCl-saturated acetic acid. The observed regioselectivity apparently remains confined to carbamoyl and possibly acyl radicals and to - M-effect substituents in 3-position.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 180
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 117 (1984) 
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 181
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 117 (1984) 
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 182
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 117 (1984), S. 1424-1435 
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: On the Reaction of 2-Pyrrolecarbaldehyde with Hetero-substituted Ethenes3H-Pyrrolizines 1 have been obtained from reactions of 2-pyrrolecarbaldehyde with ethenylphosphonates 2 and the phosphane oxide 5, respectively, the ratio of products depending on the structure of the educts. On varying the reaction conditions a controlled synthesis of both isomers 1e/f was achieved. Pyrrolizines, formed in a reaction of 2 pyrrolecarbaldehyde with ethenyl phenyl sulfone (3), could not be isolated since the reaction proceeded to give more complex pyrrolizine derivatives and the cyclazine 11. A mechanism is proposed for this multistep reaction. N-Alkylation of 2-pyrrolecarbaldehyde with dihaloalkanes has been carried out using phase transfer catalysis.
    Notes: Umsetzungen des 2-Pyrrolcarbaldehyds mit Ethenylphosphonaten 2 und dem Phosphanoxid 5 führten zu 3H-Pyrrolizinen 1, wobei das Mengenverhältnis der gebildeten Isomeren von der Struktur der Edukte abhängt. In einem Falle (1e/1f) gelang die gezielte Synthese beider Isomeren durch Variation der Reaktionsbedingungen. Die aus 2-Pyrrolcarbaldehyd und Ethenylphenylsulfon (3) entstandenen Pyrrolizine 1e/f reagieren weiter unter Bildung komplexer Pyrrolizinderivate und des Cyclazins 11. Für diese Mehrstufenreaktion wird ein Mechanismus vorgeschlagen. Unter Phasentransfer-Bedingungen gelingen Alkylierungen des 2-Pyrrolcarbaldehyds mit Dihalogenalkanen.
    Additional Material: 3 Tab.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 183
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 117 (1984), S. 1400-1423 
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Anodic Oxidation of OrganoboranesOrganoboranes are converted into more easily oxidizable borates by reaction with nucleophiles and the alkyl groups are dimerized by anodic oxidation. The oxidation potentials (Ep) of the borates depend strongly on the nature of the complexing nucleophile, for instance Ep = +0.37V (vs. SCE) with OH- or +1.65V with tetrahydrofuran. The dimer yields are optimized with trioctylborane (5) by variation of the electrode material and the electrolyte. At the platinum anode in sodium hydroxide-methanol/tetrahydrofuran yields of 80% are obtained for acyclic alkyl groups, and lower ones for cycloalkyl groups. They exceed those obtained by the Kolbe electrolysis or the oxidation with neutral hydrogen peroxide and they are comparable to those of the AgNO3 oxidation. - The selective preparation of unsymmetrical products from borates with different alkyl groups is not possible, the dimerization proceeds likely via free radicals that couple statistically. Good yields of unsymmetrical coupling products are achieved, when one olefin is used in excess. With chloro-, ethoxy-, acetoxy-, and aryl-substituted alkyl groups the dimers are obtained in 21 - 66% yield, with bromide the yield are lower and with nitriles the dimerization fails.
    Notes: Organoborane werden durch Nucleophile in leichter oxidierbare Borate übergeführt und die Alkylreste durch anodische Oxidation dimerisiert. Die Oxidationspotentiale (Ep) der Borate werden stark vom komplexierenden Nucleophil beeinflußt, z. B. Ep = +0.37V (gKE) mit OH- oder + 1.65 V mit Tetrahydrofuran. Mit Trioctylboran (5) werden die Dimerenausbeuten (10) durch Variation von Elektrodenmaterial und Elektrolyt optimiert. An der Platinanode in KOH-Methanol/Tetrahydrofuran liegen die Ausbeuten für acyclische Alkylreste um 80%, die für Cycloalkane niedriger. Sie übertreffen die der Kolbe-Elektrolyse oder der Oxidation mit neutralem Wasserstoffperoxid und sind denen bei der Oxidation mit Silbernitrat vergleichbar. - Die selektive Darstellung unsymmetrischer Produkte aus Boraten mit unterschiedlichen Alkylresten gelingt nicht; die Dimerisierung verläuft wahrscheinlich über freie Radikale, die statistisch kuppeln. Gute Ausbeuten an unsymmetrischen Kupplungsprodukten werden jedoch erzielt, wenn ein Olefin im Überschuß eingesetzt wird. Mit chlor-, ether-, ester- und arylsubstituierten Alkylresten erhält man Dimere mit 21 - 66% Ausbeute. Mit Bromiden gelingt die Kupplung schlecht, mit Nitrilen überhaupt nicht.
    Additional Material: 12 Tab.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 184
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 117 (1984), S. 2369-2381 
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Hetero-π-Systems, 9. About the Relationships between Silaethenes and MethylsilylenesSilaethenes 1 and the isomeric methylsilylenes 2 are separately existing species, but can readily be interconverted in an argon matrix via a photochemically induced 1,2-H shift. In case of the thermal excitation in the gas phase examples for both directions have been detected spectroscopically: the isomerisation of a silaolefin into the corresponding silylene (1d → 2d) and the formation of a silene from a silylene (2f → 1f).
    Notes: Die Silaolefine 1 und dazu isomeren Methylsilylene 2 sind getrennt existenzfähige Spezies, lassen sich in einer Argonmatrix aber über eine photochemisch induzierte 1,2-H-Wanderung leicht ineinander umwandeln. Bei thermischer Anregung in der Gasphase ist sowohl die Isomerisierung eines Silaolefins zum zugehörigen Silylen (1d → 2d) als auch eines Silylens zum entsprechenden Silen (2f → 1f) direkt spektroskopisch nachweisbar.
    Additional Material: 2 Ill.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 185
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 117 (1984), S. 2469-2478 
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Cyclopropenes as Complex Ligands: η4-Vinylketene Complexes of Manganese, Vanadium, and Cobalt; Preparative and X-ray Crystallographic ResultsThe reaction of 1,2,3-triphenylcyclopropene with (η5-C5H5)Mn(CO)3, (η5-C5H5)V(CO)4, (η5-C5H5)Co(CO)2 and Co2(CO)8 yields via ring opening and carbonylation the new compounds LMn(C5H5)CO (1), LV(C5H5)(CO)2 (2), LCo(C5H5) (3, 4) and L2Co2(CO)4 (6) (L = η4-C3Ph3HCO), respectively. In the reaction with (η5-C5H5)Co(CO)2 additionally the formation of 2,3-diphenylindenone (5) is observed. The X-ray structures of 1, 3 and 5 have been determined.
    Notes: Die Umsetzung von 1,2,3-Triphenylcyclopropen mit (η5-C5H5)Mn(CO)3, (η5-C5H5)V(CO)4, (η5-C5H5)Co(CO)2 und Co2(CO)8 ergibt unter Ringöffnung und Carbonylierung die neuen Verbindungen LMn(C5H5)CO (1), LV(C5H5)(CO)2 (2), LCo(C5H5) (3, 4) bzw. L2CO2(CO)4 (6) (L = η4-C3Ph3HCO). Bei der Reaktion mit (η5-C5H5)Co(CO)2 wird außerdem die Bildung von 2,3-Diphenylindenon (5) beobachtet. Die Röntgenstrukturen von 1, 3 und 5 wurden bestimmt.
    Additional Material: 3 Ill.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 186
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 117 (1984), S. 2510-2523 
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Deamination Reactions, 401). Decomposition of 3,3-, 5,5-, and 7,7-Dimethyl-2-norbornanediazonium Ionsgem.-Dimethylnorbornyl cations (3, 5) were generated by decomposition of optically active diazonium ion precursors. 6,1- and 6,2-H shifts were detected by structural isomerization and racemization, respectively. Product distributions and optical activities were profoundly affected by the polarity of the solvent. In weakly polar solvents, substitution reactions were associated with much less racemization than hydrogen shifts. Our observations are incompatible with equilibrating open ions but are reasonably explained in terms of unsymmetrical ion pairs.
    Notes: gem.-Dimethylnorbornylkationen (3,5) wurden durch Zerfall optisch aktiver Diazonium-Ionen erzeugt. 6,1- und 6,2-H-Verschiebungen wurden durch Strukturisomerisierung bzw. Racemisierung nachgewiesen. Die Polarität des Lösungsmittels hatte einen starken Einfluß auf Verteilung und optische Aktivität der Produkte. In schwach polaren Lösungsmitteln war die Substitution mit deutlich weniger Racemisierung verbunden als die H-Verschiebung. Unsere Beobachtungen sind mit äquilibrierenden, offenen Carbokationen unvereinbar, werden aber durch unsymmetrische Ionenpaare plausibel gedeutet.
    Additional Material: 5 Tab.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 187
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 117 (1984), S. 2524-2526 
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Addition of Carboxylic Acids to (1S)-5,5-Dimethylbicyclo[2.2.1]hept-2-eneProtonation of the title compound 5 induced Wagner-Meerwein rearrangement and 6,2(6,1)-hydride shifts, depending on the polarity of the acid (trifluoroacetic, acetic, and 2-ethylhexanoic acid). The optical purity of 5,5-dimethyl-2-norbornyl esters (7) exceeded that of 7,7-dimethyl-2-norbornyl esters (9). The results are interpreted in terms of asymmetric ion pairs which are tighter than those involved in deamination reactions.
    Additional Material: 1 Tab.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 188
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 117 (1984), S. 2538-2541 
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Cesium Effect in C-C-Bond Forming Reactions Yielding Large Hydrocarbon RingsC-C-bond formations of the Wurtz type following the Müller-Röscheisen procedure [alkali metal + tetraphenylethene (TPE)] leading to [2n]paracyclophane rings 2 have been carried out, comparing sodium, potassium, and cesium as metals. As fig. 1 shows, the selectivity of the oligomer formation starting from 1,4-bis(chloromethyl)benzene (1a) is strongly dependent on the alkali metal used. Sodium/TPE besides 2b predominantly yields the higher oligomers 2c - e. Use of cesium metal/TPE leads to 2b preferentially. With potassium metal/TPE all oligomers 2b - e are obtained in low yields or traces, respectively. According to these results, the oligomer formation in carbocyclic ring systems can be steered by the type of alkali metal applied; cesium seems to favour the formation of conformationally more rigid rings (like 2b).
    Additional Material: 1 Ill.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 189
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 117 (1984), S. 2580-2596 
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Intramolecular [4 + 3] Cycloaddition of Allylium-2-olates (Oxallyls) to the Furan Nucleus: Synthesis of Oxy-bridged Octahydro-azulenes and -benzocycloheptenesThe grignard reagents prepared from the 2-(ω-chloroalkyl)furans 3b, c can be acylated with the anhydrides or chlorides of chloroacetic, dichloroacetic, and α-chloropropionic acid to form the ω-furyl-substituted α-chloro ketones 1a - d. Treatment of 1 with the lithium perchlorate/triethylamine reagent affords the octahydroepoxyazulenones 2a - c and -1H-benzocycloheptenone 2d, respectively. In the case of 2b and c the exo-connection at C-8a, i.e. trans-anellation of the carbocyclic rings, is preferred.
    Notes: Die aus den 2-(ω-Chloralkyl)furanen 3b, c hergestellten Grignard-Verbindungen können mit den Anhydriden oder Chloriden von Chloressigsäure, Dichloressigsäure und α-Chlorpropionsäure acyliert werden. Die so gebildeten ω-furylsubstituierten α-Chlorketone 1a - d liefern bei der Behandlung mit dem Lithiumperchlorat/Triethylamin-Reagens die Octahydroepoxyazulenone 2a - c und das Octahydroepoxy-1H-benzocycloheptenon 2d. Im Falle von 2b und c ist die exo-Verknüpfung an C-8a, d. h. die trans-Anellierung der carbocyclischen Ringe, bevorzugt.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 190
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 117 (1984), S. 2644-2659 
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Naphtho[b]cycloheptatrienylidene - a Carbene of the Tropylidene Series with Novel PropertiesNaphtho[b]tropylidene (3) possesses a [15]annulene skeleton. It can be generated by flash solvolysis of the sodium salt of naphthotropone tosylhydrazone (4′) in the gas-phase. Thus 1- and 2-methylanthracene (11 and 12) are formed. The decisive step is a carbene carbene rearrangement to anthrylcarbene 6 and 10, respectively. The reaction is position-selective. Intermediates in these reactions should be the bicyclic compounds 5 and 7. In the condensed phase 3 reacts with olefins to afford cycloaddition products 16 and insertion products 17. The cycloaddition via the intermediate anthrylcarbene 6 to 18 is only a side-reaction. The bicycle system 5 formed in the carbene carbene rearrangement could be trapped by dienes to give 21. Non-stereospecific cycloaddition, allyl insertion as well as competition experiments with olefin/diene mixtures suggest an equilibrium mixture of singlet-3⇄ triplet-3⇄ bicycle 5.
    Notes: Naptho[b]tropyliden (3) besitzt ein [15]Annulen-Gerüst. Es kann durch Blitzthermolyse des Natriumsalzes des Naphthotropon-tosylhydrazons 4′ in der Gasphase erzeugt werden. Hierbei werden 1- und 2-Methylanthracen (11 und 12) gebildet. Als entscheidender Schritt läft dabei eine Carben-Carben-Umlagerung zum Anthrylcarben 6 bzw. 10 ab. Die Reaktion selbst ist positionsselektiv. Als Zwischenstufen dürften die Bicyclen 5 und 7 auftreten. In kondensierter Phase reagiert 3 mit Olefinen unter Bildung von Cycloadditionsprodukten 16 und Insertionsprodukten 17. Die Cycloaddition über das intermediäre Anthrylcarben 6 zu 18 verläuft lediglich als Nebenreaktion. Der in einer Carben-Carben-Umlagerung gebildete Bicyclus 5 konnte durch Diene zu 21 abgefangen werden. Nicht-stereospezifische Cycloaddition, Allylinsertion sowie Konkurrenzexperimente mit Olefin/Dien-Gemischen legen für 3 ein Gleichgewichtsgemisch Singulett-3 ⇄ Triplett-3 ⇄ Bicyclus 5 nahe.
    Additional Material: 3 Tab.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 191
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 117 (1984), S. 2622-2643 
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Formation and Reactivity of 1-Phosphoryl-1-(phosphoryloxy)allyl Anions and Related CompoundsThe formation of 1-heterosubstituted 1-phosphorylallyl anions of type 1A from the corresponding vinyl or allyl phosphonates is described. The reactivity in reactions with alkyl halides and carbonyl compounds is investigated. For preparative purposes neither the sulfur derivative 11A nor the oxygen derivatives 16A, 19A, 23A, and 29A show sufficiently high reactivity and selectivity. Only the 3-silylated derivative 25A reacts regioselectively with carbonyl compounds via Wittig-Horner olefination to give functionalized dienes 26 in moderate yields. From those it is possible to remove the phosphoryl, silyl or phosphoryloxy group selectively. Reactivity of dienes 26 in Diels-Alder reactions is poor.
    Notes: Die Bildung von in 1-Stellung heterosubstituierten 1-Phosphoryl-allyl-Anionen vom Typ 1A aus den entsprechenden Vinyl- oder Allylphosphonaten wird beschrieben und ihre Reaktivität gegenüber Alkylhalogeniden und Carbonylverbindungen untersucht. Weder das Schwefel-Derivat 11A noch die Sauerstoff-Derivate 16A, 19A, 23A und 29A besitzen für präparative Nutzung hinreichend hohe Reaktivität und Selektivität. Nur das in 3-Stellung silylierte Derivat 25A reagiert mit Carbonylverbindungen regioselektiv unter Wittig-Horner-Olefinierung in befriedigenden Ausbeuten zu den funktionalisierten Dienen 26. Aus diesen läßt sich selektiv die Phosphoryl-, die Silyl- oder Phosphoryloxygruppe abspalten. Die Reaktivität der Diene 26 in Diels-Alder-Reaktionen ist gering.
    Additional Material: 4 Tab.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 192
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 117 (1984), S. 2693-2702 
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Low Coordinated Phosphorus Compounds, 27. Synthesis and Reactions of EthynylphosphaalkenesReactions of the alkyne grignards 2a, b with P-chlorophosphaalkenes 1a, b yield the ethynylphosphaalkenes 5a - d in high yields. 5a, b, d undergo [2 + 2]-cycloaddition forming the 1,3-diphosphetanes 7a, b, d. The structures of 7 are confirmed by NMR spectroscopy and, in part, by X-ray structure determination. With 2,3-dimethyl-1,3-butadiene 5a - d form the 1,2,3,6-tetra-hydrophosphinines 8a - d via [2 + 4]-cycloaddition.
    Notes: Die Umsetzung der P-Chlorphosphaalkene 1a, b mit den Grignard-Alkinen 2a, b liefert die Ethinylphosphaalkene 5a - d in hoher Ausbeute. Durch [2 + 2]-Cycloaddition entstehen daraus 1,3-Diphosphetane 7a, b, d, deren Struktur mittels NMR-Spektroskopie und Röntgenbeugung ermittelt wurde. Mit 2,3-Dimethyl-1,3-butadien erfolgt [2 + 4]-Cycloaddition zu den 1,2,3,6-Tetrahydrophosphininen 8.
    Additional Material: 3 Ill.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 193
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 117 (1984), S. 2745-2760 
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Synthesis and Structure of 2,6-Dicyanobicyclo[3.3.1]nona-2,6-dienes and 2,6-DicyanobarbaralanesThe zinc iodide-catalyzed addition of trimethylsilyl cyanide to bicyclo[3.3.1]nonane-2,6-dione (5) yields the sterically defined O-silylated cyanohydrin 9. Trichlorophosphane oxide in pyridine converts the latter to the unsaturated dinitrile 7c. Depending on the amount of N-bromosuccinimide used, the bromination of the dinitrile 7c affords either a mixture of the monobromo- (10) and the dibromodinitrile 7d or pure dibromodinitrile 7d. With sodium methoxide in methanol the monobromodinitrile 10 is converted via concerted dehydrobromination to 2,6-dicyanobarbaralane (8c) The latter is formed almost quantitatively on debromination of the dibromodinitrile 7d with zinc/copper reagent, while sodium methoxide yields the 4-bromo-2,6-dicyanobarbaralane (12). All reactions proceed smoothly in high yields. X-ray structural parameters for bicyclo[3.3.1]nona-2,6-dienes (i. e. 7c, d and 10) and a barbaralane (i. e. 12) have for the first time become available.
    Notes: Zinkiodid-katalysierte Addition von Trimethylsilylcyanid an Bicyclo[3.3.1]nonan-2,6-dion (5) ergibt das sterisch einheitliche O-silylierte Cyanhydrin 9, das mit Trichlorphosphanoxid in Pyridin zum ungesättigten Dinitril 7c umgesetzt wird. Je nach N-Bromsuccinimid-Menge entsteht bei der Bromierung des Dinitrils 7c ein Gemisch aus Monobrom- (10) und Dibromdinitril 7d oder reines Dibromdinitril 7d. Das Monobromdinitril 10 wird durch eine konzertierte Dehydrobromierung mit Natriummethanolat in Methanol in das 2,6-Dicyanbarbaralan (8c) übergeführt. Dieses bildet sich fast quantitativ durch Debromierung des Dibromdinitrils 7d mit Zink/Kupfer, während die Dehydrobromierung von 7d mit Natriummethanolat in Methanol 4-Brom-2,6-dicyanbarbaralan (12) ergibt. Alle Reaktionen verlaufen sehr glatt und mit hohen Ausbeuten. Durch Röntgenstrukturbestimmung der Dinitrile 7c, d und 10 sowie des 4-Brom-2,6-dicyanbarbaralans (12) wurden die exo-Konfiguration der Bromatome von 7d und 10 und erstmal geometrische Parameter von Bicyclo[3.3.1]nona-2,6-dienen und einem Barbaralan ermittelt.
    Additional Material: 5 Ill.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 194
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 117 (1984), S. 2761-2778 
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Photochemical Elimination of Nitrogen from 1-(1-Alkenyl)-4-tert-butyl-1,4-dihydro-5H-tetrazol-5-ones. Competition between Addition of Methanol and Cyclization of a Dipolar IntermediateThe 4-tert-butyl-1-vinylterazolones 12a - c and the tetrazolones 13 and 14 are synthesized from the 5-chlorotetrazole 7 and the tetrazolone 9 via several routes. Bis(benzonitrile)palladium dichloride catalyses the O → N-Claisen rearrangement 8 → 11, the allyl → vinyl rearrangements 11a → 12b and 11b → 12c, as well as the equilibration 13 → 14. On 254 nm photolysis of the vinyltetrazolones 12 nitrogen is extruded and cyclic and/or acylic products of primary photo-intermediates are formed: In [D3]acetonitrile as solvent, 77% of 1-tert-butylimidazolone 16 arises from 12a, while the tetrazolones 12b, c produce only complex mixtures. In methanol as solvent, the methanol adduct 20a (23%) of the intermediate imidazolone 15a and the acyclic N-(1,2-dimethoxyethyl)urea 22a (32%) are obtained besides 45% of 16. In contrast, from 12c in methanol the corresponding urea 22c is formed almost quantitatively as the only product. In [D4]methanol solution of (E,Z)-12b a ratio of 4-methoxyimidazolidinone 20 b to the diastereomeric ureas 22 b of 22: 78 is observed. With decreasing amounts of [D4]methanol in [D4]methanol/[D3]acetonitrile mixtures, the imidazolidinone 20 b increases at the expense of the ureas 22 b. A 20 b: 22 b ratio of 98: 2 is reached in [D3]acetonitrile containing 3-6% [D4]methanol. This indicates a competition between the cyclization (affording 20 b via 15 b) and the methanol addition (producing 22 b via 21 b) of a dipolar photo-intermediate. The structure of the photo-products are confirmed by independent synthesis of 16 and by their high field proton and carbon-13 NMR spectra.
    Notes: Aus dem 5-Chlortetrazol 7 und dem Tetrazolon 9 werden auf verschiedenen Wegen die 4-tert-Butyl-1-vinyltetrazolone 12a - c sowie die Tetrazolone 13 und 14 hergestellt. Bei der 254-nm-Photolyse der 1-Vinyltetrazolone 12 erhält man in Abhängigkeit von Struktur und Reaktionsbedingungen das Imidazolon 16, die 4-Methoxyimidazolidinone 20 und/oder die N-(1,2-Dimethoxyalkyl)harnstoffe 22. Die Ergebnisse sprechen für eine Konkurrenz zwischen Cyclisierung (→ 15b → 20b) und Methanol-Addition (→ 21b → 22b) einer dipolaren Photozwischenstufe. Die Struktur der Photoprodukte wird durch unabhängige Synthese von 16 sowie Hochfeld-1H-und 13C-NMR-Spektren bewiesen.
    Additional Material: 6 Tab.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 195
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 117 (1984), S. XXIII 
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 196
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 117 (1984), S. 3169-3174 
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Organometallic Lewis Acids, XV1). Cyclodimerization of 2-Butyne and 2-Pentyne at Pentacarbonyl(tetrafluoroborato)rhenium to a Coordinated Methylenecyclobutene DerivativeThe reactions of pentacarbonyl(tetrafluoroborato)rhenium, (OC)5ReFBF3 (1a), with 2-butyne and 2-pentyne give the methylenecyclobutene complexes [(CO)5Re(C8H12)]+BF4- (2) and [(CO)5Re(C10H16)]+BF4- (3). From 2, 3 the methylenecyclobutene ligands can be liberated by halide ions.
    Additional Material: 1 Tab.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 197
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Metal π-Complexes of Benzene Derivatives, XXIV1). 1H NMR Coordination Shift and Ring Current Quenching in Sandwich Complexes as Studied for Bis(η6-[10]paracyclophane)chromium(0)The title compound was prepared by means of metal atom-ligand vapor cocondensation. Its most conspicuous feature, the well defined disposition of 20 methylene groups in the periphery of the title complex is employed to gauge via 1H NMR the coordination induced quenching of the aromatic ring current in arenes.
    Additional Material: 1 Ill.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 198
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 117 (1984), S. 3194-3204 
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Gas Phase Chemistry of Metastable Thiophene Cation RadicalsThe unimolecular loss of acetylene from metastable thiophene cation radicals (1) has been studied by means of 13C and deuterium labelling and semi-empirical molecular orbital calculations (MINDO/3). It is shown that direct loss of acetylene from unrearranged 1 amounts to less than 5.3%:1.2% involving C-α/C-β and 4.1% for loss of C-β/C-β for dissociations with lifetimes t ≈ 10-5.5s. More than 94% of the long-lived molecular ions rearrange prior to dissociation, and it is shown that the majority of 1 (64.5%) undergoes complete carbon atom scrambling, presumably via the tricyclic cation radical 12. 30.2% of 1 suffer a degenerate isomerization involving either the pyramidal cation radical 11 or the bicyclic cation radicals 13, the latter undergoing a “Merry-go-round” rearrangement. At shorter lifetimes of 1 (t ≈ 10-6.5S) the isomerization pattern is only slightly changed. In agreement with previous kinetic studies of Butler and Baer8) it is shown by collisional activation mass spectrometry and the MINDO/3-study that the structure of the C2H2S+. ion generated from 1 is best described as that of the thioketene cation radical (18) and not of the isomeric mercaptoacetylene 21. The loss of both deuterated and 13C-labelled acetylene from labelled 1 is subject to a kinetic isotope effect.  -  The syntheses of the various isotopomers are described.
    Notes: Die unimolekulare Acetylen-Eliminierung aus den metastabilen Molekül-Ionen des Thiophens (1) wird durch eine Kombination von MINDO/3-Rechnungen und 13C- und D-Markierung analysiert. Es wird gezeigt, daß Ionen mit einer Lebensdauer von ca. 10-5.5 s nur untergeordnet zu einem direkten Zerfall befähigt sind: 1.2% für die C2H2-Abspaltung aus der C-α/C-β- und 4.1% für die aus der C-β/C-β-Position. Mehr als 94% der metastabilen Ionen erleiden vor ihrem Zerfall eine Isomerisierung, die zu 64.5% über das tricyclische Radikalkation 12 verläuft. Die Umlagerung über das pyramidale Ion 11 oder in Form einer „Merry-go-round“-Isomerisierung über 13 findet zu 30.2% statt. Bei kürzeren Zerfallszeiten (t ≈ 10-6.5s) ändert sich das Verhalten von 1 nicht wesentlich. In Übereinstimmung mit den kinetischen Untersuchungen von Butler und Baer8) belegen sowohl unsere Stoßaktivierungsuntersuchung als auch die MINDO/3-Analyse, daß den resultierenden C2H2S+.-Ionen die Struktur eines Thioketen-Radikalkations (18) und nicht des isomeren Mercaptoacetylens (21) zukommt. Der Verlust von deuteriertem bzw. 13C-markiertem Acetylen ist mit einem kinetischen Isotopieeffekt verknüpft.  -  Die Synthesen der verschiedenen Isotopomeren werden beschrieben.
    Additional Material: 4 Tab.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 199
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: (η2-Alkene)(η5-cyclopentadienyl)organylnickel ComplexesThe (cyclopentadienyl)organylnickel species A, which is formed by reaction of nickelocene (1) with organolithium or organomagnesium halides, can be stabilized by complexation to the C = C bond of an olefin. Below ca. -30°C, the organyllithium compounds react with 1 and olefins to give the (η2-alkene)(η5-cyclopentadienyl)organylnickel complexes 2a-j (alkene: ethylene), 7-14 (alkene: propene) as well as the related methylnickel derivatives 15-17 and 22-25 with alkenes of different types.  - Only one C=C bond of butadiene complexes to give 18, while in the case of substituted 1,3-alkadienes the least substituted double bond is complexed. Temperature dependent NMR spectra are observed; in the case of the CH2=CHR and CH2=CR1R2 complexes as the result of rotation of the alkene around the coordination axis two rotamers can be observed at ca. -60°C. The ability of the organylnickel bond to add to complexed ethylene decreases in the order Ph-Ni (to 28) 〈 c-C3H5-Ni (to 29) 〈 Me-Ni (to 2e). 2d catalyzes the oligomerisation of ethylene at 120°C to give a mixture of butene, hexene, and octene.
    Notes: Das bei der Umsetzung von Nickelocen (1) mit Organylmagnesiumhalogenid bzw. Organyllithium primär entstehende (Cyclopentadienyl)organylnickel A läßt sich durch Komplexierung an die C = C-Bindung eines Olefins stabilisieren. Unterhalb ca. -30°C lassen sich mit Organyllithium die (η2-Alken)(η5-cyclopentadienyl)organylnickel-Komplexe 2a-j (Alken: Ethylen), 7-14 (Alken: Propen) sowie die Methylnickel-Derivate gleichen Typs 15-17 und 22-25 mit verschiedenartigen Alkenen erhalten. Bei Butadien komplexiert nur eine C = C-Bindung zu 18, bei unsymmetrisch substituierten Butadienen ist dies die geringer substituierte Bindung.  -  Rotation des Alkens um die Koordinationsbindungsachse bedingt temperaturabhängige NMR-Spektren; bei Alkenen der Typen CH2=CHR und CH2=CR1R2 sind bei ca. -60°C zwei Rotamere beobachtbar. Die Fähigkeit der Organyl-Nickel-Bindung zur Addition an komplexiertes Ethylen sinkt in der Reihe Ph-Ni (zu 28) 〈 c-C3H5-Ni (zu 29 〈 Me-Ni (zu 2e). 2d katalysiert bei 120°C die Oligomerisierung von Ethylen zu einem Gemisch von Buten, Hexen und Octen.
    Additional Material: 15 Tab.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 200
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 117 (1984), S. 3320-3324 
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Reductive Displacement of the Acetate Group in Allyl, Propargyl, and Benzyl Acetates by NaBH4/NiCl2 · 6 H2OThe combination of NiCl2 · 6 H2O and NaBH4 provides an effective system for reductive removal of the acetate group of allyl, propargyl, and benzyl acetates. Sterically less hindered allyl acetates are converted preferentially to the corresponding alkanes (Table 1).
    Additional Material: 1 Tab.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
Close ⊗
This website uses cookies and the analysis tool Matomo. More information can be found here...