ALBERT

All Library Books, journals and Electronic Records Telegrafenberg

feed icon rss

Your email was sent successfully. Check your inbox.

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

Proceed reservation?

Export
  • 1
    Electronic Resource
    Electronic Resource
    [s.l.] : Nature Publishing Group
    Nature 194 (1962), S. 439-441 
    ISSN: 1476-4687
    Source: Nature Archives 1869 - 2009
    Topics: Biology , Chemistry and Pharmacology , Medicine , Natural Sciences in General , Physics
    Notes: [Auszug] The derivation of the quantitative relation Jl between adsorption and surface tension from thermodynamics by Gibbs1 provoked attempts at an experimental verification of this equation. Such methods as the bubble method, the microtome method and, more recently, radioactive measurements have been used ...
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 2
    ISSN: 1476-4687
    Source: Nature Archives 1869 - 2009
    Topics: Biology , Chemistry and Pharmacology , Medicine , Natural Sciences in General , Physics
    Notes: [Auszug] Strong deviations from bulk metal behaviour are predicted for the electronic susceptibility and specific heat, #el and Cel, when FIG. 1 Electronic magnetic susceptibility xe\ á°f the Pd clusters in the quantum-size regime. In the range 2-300 K the measurements were made with a ...
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 3
    Electronic Resource
    Electronic Resource
    [s.l.] : Nature Publishing Group
    Nature 367 (1994), S. 716-718 
    ISSN: 1476-4687
    Source: Nature Archives 1869 - 2009
    Topics: Biology , Chemistry and Pharmacology , Medicine , Natural Sciences in General , Physics
    Notes: [Auszug] It has been shown2 4 that chemical synthetic methods can be used to prepare metal-cluster compounds with well defined stoichiometry, in which polyhedral metal cores containing up to several hundreds of atoms are surrounded by ligand shells. Because the size and structure of all of ...
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 4
    Electronic Resource
    Electronic Resource
    New York, NY [u.a.] : Wiley-Blackwell
    Biotechnology and Bioengineering 33 (1989), S. 1445-1460 
    ISSN: 0006-3592
    Keywords: Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: A previously isolated cellodextrin glucohydrolase (β-glucosidase) from Trichoderma reesei QM 9414 is characterized using β-1,4-glucose oligomers with defined degrees of polymerization as soluble substrates. The enzyme splits off glucose units from the nonreducing chain ends of cellooligomers. Besides this hydrolytic activity there is also evidence for transfer activity depending on the concentration and degree of polymerization of substrates. Concentration-time-course data have been gathered for the degradation of cellobiose, cellotriose, cellotetraose, cellopentaose, and cellohexaose covering a wide range of enzyme and substrate concentrations. A Michaelis-Menten type kinetic model has been developed, which is able to satisfactorily describe the complex system of parallel and series reactions during the conversion of oligomers to glucose. The only kind of inhibition considered is competitive inhibition by the final product glucose. The model takes into account the formation of multiple enzyme-substrate complexes and is limited to those conditions, in which no transglucosylation products are observed. Cellodextrins with higher degrees of polymerization are found to be better substrates for this enzyme than is the dimer cellobiose.
    Additional Material: 12 Ill.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 5
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Zeitschrift für anorganische Chemie 621 (1995), S. 1147-1152 
    ISSN: 0044-2313
    Keywords: Metal clusters ; metal colloids ; differential scanning calorimetry ; thermal behavior ; decomposition enthalpy ; bond energy ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Differential Scanning Calorimetric Investigations of Large Transition Metal ClustersThe thermal behavior of various ligand stabilized transition metal clusters is investigated by means of differential-scanning-calorimetry (DSC). In the case of the cluster Au55(PPh3)12Cl6 the decomposition temperature of 131°C, the decomposition enthalpy of 114 J/g, as well as the bond energy of 75.6 kJ/mole can be determined. Moreover, detailed informations about the mechanism of cluster degradation into Ph3PAuCl, (Ph3P)2AuCl, PPh3, and metallic gold can be made in combination with impedance spectroscopic measurements. The derivatives Au55[P(p-tolyl)3]12Cl6 and Au55[P(p-anisyl)3]12Cl6 behave similar like the PPh3 substituted clusters. The thermolysis of the water-soluble cluster Au55(TPPMS-Na)12Cl6 proceeds completely different, what can be attributed to the formation of (TPPMS-Na)Au(TPPMS). The DSC diagram of the platinum cluster Pt309phen*36O30 shows no decomposition signal between 25 and 400°C although degradation occurs. This must be due to compensating processes of unknown nature. The thermal behavior of the larger 5-, 7-, and 8-shell palladium clusters documents the relation to the metallic state. The points of decomposition are found between 130 and 115°C, the decomposition enthalphies between 150 and 60 J/g, and the bond energies between 58-56 kJ/mole what is slightly smaller than in the bulk metal with 62.8 kJ/mole.
    Notes: Das thermische Verhalten verschiedener ligandstabilisierter Übergangsmetallcluster wird mittels Differenz-Scanning-Kalorimetrie (DSC) untersucht. Im Falle des Clusters Au55(PPh3)12Cl6 können neben der Zersetzungstemperatur von 131°C auch die Zersetzungsenthalpie von 114 J/g und die Bindungsenergie von 75,6 kJ/mol bestimmt werden. Ferner lassen sich in Kombination mit impedanzspektroskopischen Messungen auch detaillierte Angaben über den Mechanismus des Clusterabbaus in Ph3PAuCl, (Ph3P)2AuCl, PPh3 und metallisches Gold machen. Die Derivate Au55[P(p-tolyl)3]12Cl6 und Au55[P(p-anisyl)3]12Cl6 verhalten sich ähnlich wie der PPh3-substituierte Cluster. Die Thermolyse des wasserlöslichen Clusters Au55(TPPMS-Na)12Cl6 verläuft vollständig anders, was auf die Bildung von (TPPMS-Na)Au(TPPMS) zurückgeführt wird. Das DSC-Diagramm des Platinclusters Pt309phen*36O30 zeigt zwischen 25 und 400°C kein Zersetzungssignal obgleich Abbau stattfindet. Dies muß auf kompensierende Vorgänge unbekannter Natur zurückgeführt werden. Das thermische Verhalten der großen 5-, 7- und 8-schaligen Palladiumcluster dokumentiert deren Nähe zum metallischen Zustand. Die Zersetzungspunkte liegen zwischen 130 und 115°C, die Zersetzungsenthalpien zwischen 150 und 60 J/g und die Bindungsenergien bei 58-56 kJ/mol, also geringfügig niedriger als im Metall mit 62,8 kJ/mol.
    Additional Material: 3 Ill.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 6
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Zeitschrift für anorganische Chemie 415 (1975), S. 97-103 
    ISSN: 0044-2313
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Experiments on the Oxidative Addition of Thionylhalides to Transition Metal ComplexesThe complexes [(C6H5)3P]4Pd and [(C6H5)3P]2Ni(NO)Cl react with SOX2 to trans [(C6H5)3P]2PdX2 (X = Cl, Br) resp. to [(C6H5)3PX][NiX3] (X = Cl). Furthermore (C6H5)3PO and (C6H5)3PS are formed. In contrast SOCl2 is added oxidatively by [(C6H5)3P]2Ir(CO)Cl to the complex [(C6H5)3P]2Ir(CO)(Cl2)SOCl.
    Notes: Die Komplexe [(C6H5)3P]4Pd und [(C6H5)3P]2Ni(NO)Cl reagieren mit SOX2 zu trans-[(C6H5)3P]2PdX2 (X = Cl. Br) bzw. [(C6H5)3PX][NiX3] (X = Cl). Weiterhin bilden sich (C6H5)3PO und (C6H5)3PS. Im Gegensatz dazu wird SOCl2 durch [(C6H5)3P]2 Ir(CO)Cl oxydativ zu dem Komplex [(C6H5)3P]2 Ir(CO)(Cl2)SOCl addiert.
    Additional Material: 1 Ill.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 7
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Zeitschrift für anorganische Chemie 418 (1975), S. 243-246 
    ISSN: 0044-2313
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: P2J3 - a New Complex LigandP2J4 and Na2Cr(CO)5 react in benzene to the monomeric diamagnetic complex (CO)4CrP2J3. The 31P-nmr spectrum shows the presence of different bonded phosphorus atoms. The exchange of one iodine atom between the P atoms leads to a temperature dependent equilibrium with a symmetrical transition state. Triphenyl- and tricyclohexylphosphine react with (CO)4CrP2J3 to (CO)4CrPJ2 · P(C6H5)3 resp. (CO)4CrPJ2 · P(C6H11)3, probably of dimeric nature.
    Notes: P2J4 und Na2Cr(CO)5 reagieren in Benzol zu dem monomeren, diamagnetischen Komplex (CO)4CrP2J3. Das 31P-NMR-Spektrum zeigt die Anwesenheit unterschiedlich gebundener Phosphoratome. Der Austausch eines Jodatoms zwischen den P-Atomen führt zu einem temperaturabhängigen Gleichgewicht, in dem ein symmetrischer Übergangszustand auftritt. Triphenyl- und Tricyclohexylphosphin reagieren mit (CO)4CrP2J3 zu (CO)4 · P(C6H5)3 bzw. (CO)4 CrPJ2 · P(C6H11)3, wahrscheinlich dimerer Natur.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 8
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Zeitschrift für anorganische Chemie 432 (1977), S. 160-166 
    ISSN: 0044-2313
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: The Use of Elemental Phosphorus as Ligand in Iron CarbonylsWhite phosphorus and Fe2(CO)9 react in benzene at room temperature to the monomeric diamagnetic complex [(CO)4Fe]3P4. The Mössbauer spectrum proves the presence of penta- and hexacoordinated Fe atoms in the ratio 1:2. The i.r. spectrum also suggests different bonded Fe(CO)4 groups. As the 31P-n.m.r. spectrum shows, the 4 P atoms are equivalent. It is supposed that one Fe(CO)4 group fluctuates between the P atoms. At 70°C P4 and Fe2(CO)9 react to the polymeric diphosphorous complex [(CO)3FeP2]n. Its synthesis succeeds also with Fe(CO)5 and P4 under u.v. irradiation. Additionally [(CO)4Fe]3P4 can be decomposed to [(CO)3FeP2]n by warming or irradiation. The Mössbauer spectrum of this complex shows equivalent Fe atoms with the coordination number 6. Possible structures are discussed.
    Notes: Weißer Phosphor und Fe2(CO)9 reagieren in Benzol bei Raumtemperatur zu dem monomeren, diamagnetischen Komplex [(CO)4Fe]3P4. Das Mössbauerspektrum belegt die Anwesenheit fünffach und sechsfach koordinierter Fe-Atome im Verhältnis 1:2. Auch das IR-Spektrum legt unterschiedlich gebundene Fe(CO)4-Gruppen nahe. Wie das 31P-NMR-Spektrum zeigt, sind alle 4 P-Atome äquivalent. Es wird angenommen, daß eine Fe(CO)4-Gruppe zwischen den P-Atomen fluktuiert. Bei 70°C setzen sich P4 und Fe2(CO)9 zu dem polymeren Diphosphorkomplex [(CO)3FeP2]n um. Dessen Synthese gelingt auch aus Fe(CO)5 und P4 unter UV-Bestrahlung. Ebenso kann [(CO)4Fe]3P4 durch Erwärmen oder Belichten in [(CO)3FeP2]n zersetzt werden. Das Mössbauerspektrum dieses Komplexes zeigt äquivalente Fe-Atome mit der Koordinationszahl 6. Mögliche Strukturen werden diskutiert.
    Additional Material: 5 Ill.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 9
    ISSN: 0044-2313
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Beiträge zur Chemie der Alkylverbindungen von Übergangsmetallen. 56. 2-(Dimethylaminomethyl) ferrocenyl-Derivate des Titans und Zirconiums - Grenzen der ChelatbildungAls neue Titanocen- bzw. Zirconocenkomplexe wurden das paramagnetische (η5-C5H5)2Ti(FcN) III (FcN = 2-[Dimethylaminomethyl]ferrocenyl) und das diamagnetische (η5-C5H5)2Zr(1-Camph)(FcN) IV (1-Camph = 1-Camphenyl) synthetisiert und durch Massen-, 1H- und 13C-NMR-Spektren sowie magnetische Messungen charakterisiert. Ferner wurden die Kristall- und Molekülstrukturen von (η5-C5H5)2M(FcN)2 (M = Ti I, Zr II) bestimmt. Eine M—C, N-Chelatbildung mit dem (Dimethylaminomethyl)ferrocenyl-Liganden wurde bei III (im Festkörper) und IV (in Lösung) gefunden, während diese bei I und II im kristallinen Zustand ausbleibt.
    Notes: The new paramagnetic (η5-C5H5)2Ti(FcN) III (FcN = 2-[dimethylaminomethyl]-ferrocenyl) and diamagnetic (η5-C5H5)2Zr(1-Camph)(FcN) IV (1-Camph = 1-Camphenyl) complexes were prepared and characterized by spectra and magnetic measurements. The crystal and solid phase molecular structures of (η5-C5H5)2M(FcN)2 (M = Ti I and Zr II) compounds were determined by single crystal X-ray diffraction. An M—C, N chelation of the (dimethylaminomethyl)ferrocenyl ligand was detected at compounds III (solid phase) and IV (solution), while such interaction fails at complexes I and II in crystalline phase.
    Additional Material: 3 Ill.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 10
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Zeitschrift für anorganische Chemie 595 (1991), S. 27-34 
    ISSN: 0044-2313
    Keywords: Decamethylmanganocene ; phase transition ; crystal structure ; DSC thermogram ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Phase Transition of DecamethylmanganoceneDecamethylmanganocene (Cp2*Mn) has been investigated X-ray structural analytically at 240, 225, and 125 K, to study a reversible phase transition between 255 and 238 K (DSC thermogram). At 240 K the same space group C2/c is observed as at room temperature [9], whereas after the phase transition at 225 and 125 K the space group Cmca is found. In both phases the Cp* rings are staggered and slightly slipped, but less at 225 and 125 K compared with 240 K.The phase transition is to be traced back to a change of the molecule packing in the crystal lattice: With decreasing temperature the molecules cannot be packed closer in the monoclinic phase (C2/c), because the intermolecular H … H distances already remained under the sum of the van der Waals radii. In the orthorhombic phase (Cmca) (elongation of the a-axis and contraction of the b-axis) the repulsion along the b-axis is avoided.
    Notes: Decamethylmanganocen (Cp2*Mn) wurde bei 240, 225 und 125 K röntgenstrukturanalytisch untersucht, um einen zwischen 240 und 225 K stattfindenden reversiblen Phasenübergang (DSC-Thermogramm) zu untersuchen. Bei 240 K wird dieselbe Raumgruppe C2/c beobachtet wie bei Raumtemperatur [9], während nach dem Phasenübergang bei 225 und 125 K die Raumgruppe Cmca gefunden wird. In beiden Phasen sind die Cp*-Ringe gestaffelt und leicht gegeneinander verschoben angeordnet, jedoch bei 225 und 125 K weniger als bei 240 K. Der Phasenübergang ist auf eine Packungsänderung der Moleküle im Kristallgitter zurückzuführen: Mit abnehmender Temperatur können die Moleküle in der monoklinen Phase (C2/c) sich nicht mehr dichter packen, da die intermolekularen H … H-Abstände bereits die Summe der van der Waals-Radien unterschritten haben. In der orthorhombischen Phase (Cmca) (Verlängerung der a-Achse und Kontraktion der b-Achse) wird die Repulsion entlang der b-Achse vermieden.
    Additional Material: 7 Ill.
    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...