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  • 1
    ISSN: 1572-8943
    Keywords: crystal structure ; metal(II) picolinate and quinaldinate ; thermal degradation of imidazole and pyrazole complexes
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract Complexes of the type M(Pa)2(HAz)2 and M(QA)2(HAz)2 (M=cobalt(II) and nickel(II); HPa=picolinic acid, HQa=quinaldic acid; HAz=azoles like imidazole (Him), pyrazole (HPz), benzimidazole (HBzIm) etc.) show a similar thermal behaviour. In the first step of decomposition the corresponding azolinium picolinates or quinaldinates (H2AzPa, H2AzQa) are split off with formation of polymeric mixed ligand complexes M(Pa)(Az) or M(Qa)(Az). X-ray analysis of Co(Qa)2(HBzIm)2 XIIIa illustrates a proton transfer and a subsequent thermal removal of benzimidazolinium quinaldinate (H2BzImQa): Hydrogen bridges from pyrrole nitrogen of the benzimidazole to the non-coordinated oxygen of the quinaldinate predetermine the thermal initiated proton transfer. The high volatility of the heterocyclic acids and the nitrogen coordination are responsible for the formation of the mixed ligand complex Co(Qa)(BzIm) XIVa. Exceptions are the complexes M(Pa)2(HPz)2 XIa-b and M(Qa)2(HIm)2 XVIIa-b. Pyrazole is eliminated from the complexes XIa-b with formation of the solvent-free inner complex M(Pa)2 XIIa-b. From compounds XVIIIa-b quinaldic acid or their decomposition products are split off and a high temperature modification of M(Im)2 XVIIIa-b is formed at elevated temperature. XVIIIa-b are decomposed to the cyanides M(CN)2 similarly to the thermal behaviour of Cu(Im). In the first step the thermal degradation of imidazole and pyrazole adducts of copper(II) picolinates and quinaldinates is characterized by the elimination of azoles. The reason for this thermal behaviour is the weaker coordination of the azole heterocycles in copper chelate compounds.
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  • 2
    ISSN: 0044-2313
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: [(C6H5)3P]2Ni(Me3Si—C≡C—SiMe3). Preparation, Properties, and Structure of the First Stable Nickel(0) Complex with Bis(trimethylsilyl)acetyleneThe title compound is the first example of a nickel(0) complex with bis(trimethylsilyl)acetylene and obtained from (ph3P)2Ni(C2H4) and bis(trimethylsilyl)acetylene in tetrahydrofuran. The complex is characterized by some reactions, the i.r. spectrum and by a structural analysis with the aid of X-ray diffraction data. (ph3P)2Ni(Me3Si—C≡C—SiMe3) crystallizes monoclinic in the space group C2/c with four formula units per unit cell (2468 observed, independent reflexions, R = 0.038). The cell dimensions are a = 20.927, b = 13.812, c = 14.238 Å, α = γ = 90°, β = 91.02°. The molecules are monomer in crystalls. The molecule is planar with ligands arranged trigonally about the central atome but distorted to the tetrahedral complex.
    Notes: Die Titelverbindung ist das erste Beispiel für einen Nickel(0)-Komplex des Bis-trimethylsilylacetylen und wird aus (ph3P)2Ni(C2H4) und dem Alkin in Tetrahydrofuran erhalten. Der Komplex wird durch Reaktionen, das IR-Spektrum und mittels einer Röntgenstrukturanalyse charakterisiert. (ph3P)2Ni(Me3Si—C≡C—SiMe3) kristallisiert monoklin in der Raumgruppe C2/c mit vier Formeleinheiten pro Elementarzelle (2468 unabhängige, beobachtete Reflexe, R = 0,038). Die Gitterabmessungen sind a = 20,927 Å, b = 13,812 Å, c = 14,238 Å, α = γ = 90°, β = 91,02°. Die Moleküle liegen im Kristall monomer vor. Das Zentralatom ist trigonal-planar koordiniert, aber in Richtung eines Tetraeders verzerrt.
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  • 3
    ISSN: 0044-2313
    Keywords: Nickel complex, Ni(BPSH)2 · H2O ; bis(benzoylpyridin-p-toluensulfonylhydrazido)nickel ; heterocyclic sulfonamido chelates ; crystal structure ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Bis(benzoylpyridin-toluensulfonylhydrazido)nickel Ni(BPSH)2 · H2O  -  Relations between Structure, Redox, and Extraction Properties of Heterocyclic Sulfonamido ChelatesThe crystal structure of Ni(BPSH)2 · H2O was determined by x-ray diffraction: monoclinic, space group P21/c (Nr. 14); a = 15.077(4) Å, b = 14.901(3) Å, c = 16.335(3) Å, β = 95.74(1)°. R = 0.047 for a total of 5564 observed reflexions. Ni(BPSH)2 · H2O has a distorted tetrahedral structure with two six-membered chelate rings, one of them with a boat from. The electron system of the building blocks CNN⊖ within the chelate rings approaches that of a diazallyl group. The result is a high electron density on the sp2-hybridized donor atom N⊖ and, as a consequence, a short Ni—N⊖-distance (1.908 or 1.924 Å). The electronic properties of N⊖ also explain the high NH-acidity of the acid H(BPSH) (pks = 9,51 in 75 per cent dioxane) and the ligand field strength of BPSH⊖ which is low compared to that of other bidentate sulfonamido ligands and which is reflected in the paramagnetism of Ni(BPSH)2 · H2O.The redox behavior of metal chelates of the type, which is represented by Ni(BPSH)2 · H2O, is caused by a building block of the ligand which is also present in bipyridyl or in the 1,4-diaza-1,3-dienes. The central atoms M11 have only the function of interference factors.
    Notes: Die Kristallstruktur von Ni(BPSH)2 · H2O wurde durch Röntgenbeugung bestimmt: monoklin, Raumgruppe P21/c (Nr. 14), a = 15,077(4) Å, b = 14,901(3) Å, c = 16,335(3) Å, β = 95,74(1) ° R = 0,047 für 5564 beobachtete Reflexe. Ni(BPSH)2 ° H2O besitzt eine verzerrt tetraedrische Struktur mit zwei Chelatsechsringen, von denen einer in der Wannenform vorliegt. Die Baugruppen CNN⊖ innerhalb der Ringe weisen ein Elektronensystem auf, das sich an das einer Diazallylfunktion annähert. Die Folge davon ist eine hohe Elektronendichte auf dem sp2-hybridisierten Stickstoffhaftatom N⊖ und ein kurzer Ni—N⊖-Abstand (1,908 bzw. 1,924 Å). Die elektronischen Eigenschaften von N⊖ erklären weiterhin die hohe NH-Acidität der Säure H(BPSH) pks = 9,51 in 75% (Dioxan) und die verglichen mit anderen Sulfonamidochelatliganden geringe Ligandenfeldstärke von BPSH⊖, die sich im Paramagnetismus von Ni(BPSH)2 · H2O äußert.Das Redoxverhalten der Metallchelate des durch Ni(BPSH)2 · H2O repräsentierten Typs wird durch ein Bauelement des Liganden bestimmt, das sich im α, α′-Dipyridyl und in den 1,4-Diaza-1,3-dienen wiederfindet. Metallionen M2+ wirken über das Diazalylsystem lediglich als Störfaktoren.
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  • 4
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Zeitschrift für anorganische Chemie 620 (1994), S. 551-560 
    ISSN: 0044-2313
    Keywords: Metal complexes ; Amidines ; Oxalic derivates ; Imidazolidines ; Diazadiene ligands ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Nitrogen Derivates of Oxalic Acid as New Complexing AgentsHeterocycles with a exocylic 1,4-diaza-1, 3-diene structure 5a-d have σ-bonding and π-backbonding properties similar to the diazadienes (DAD) 1. The investigations of the molybdenum complexes 11 and 12 of the ligands 5 show a dominant σ-interaction and only a small π-backbonding, comparable with the compound (CO)4Mo(iPYC) 14, a complex of pyridinecarbaldehyde isopropylimine (iPYC).The oxalamidine (TPOA) 4 (precursor of the heterocycles 5a-d) are present in a s-trans (E/E)-form with two stable intra-molecular hydrogen bridges. 4 reacts with ferrous and cobaltous chloride to the polymer coordination compounds 8 and 9. According to the diazadiene 1 oxalamadine 4 substitutes two carbonyls in Mo(CO)6 by formation of (CO)4Mo(TPOA) 10. The coordinated ligand 4 shows in the complex 10 a s-cis(E/E)-form with respect to the free ligand and no H-bridges were observed. The crystal structures of TPOA 4 and (CO)4Mo(TPOA) 10 were determined. Cyclisation reactions on the coordinated oxalamidine are possible.
    Notes: Heterocyclen mit einer exocyclischen 1,4-Diaza-1,3-dien-Struktur 5a-d besitzen in Analogie zu den Diazadienen (DAD) 1 α-Donor und π-Akzeptoreigenschaften. Durch vergleichende Untersuchungen an deren Molybdäncarbonylkomplexen 11 und 12 konnte festgestellt werden, daß der σ-Bindungscharakter dominant ist und nur geringe π-Rückbindungsanteile vorliegen, vergleichbar mit Verbindung (CO)4Mo(iPYC) 14, einem Komplex des Pyridin-2-carbaldehyd-isopropylimins (iPYC).Der Vorläufer dieser Heterocyclen, das Oxalamidin 4 (TPOA), liegt als Molekül in einer s-trans-(E/E)-Form mit zwei stabilen intramolekularen Wasserstoffbrücken vor. 4 bildet mit Eisen(II)- bzw. Cobalt(II)-chloriden polymere Koordinationsverbindungen 8 und 9. Mit Molybdänhexacarbonyl reagiert 4 analog den Diazadienen 1 unter Substitution zweier Carbonyl-gruppen zu (CO)4Mo(TPOA) 10. In 10 liegt der Ligand 4 in der s-cis-(E/E)-Form vor, wobei keine Wasserstoffbrücken-bindungen mehr beobachtet werden. Von 4 und 10 wurden Röntgenstrukturanalysen angefertigt. Am koordinativ fixierten Oxalamidin in 10 können Cyclisierungsreaktionen durchgeführt werden.
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  • 5
    ISSN: 0044-2313
    Keywords: Dimesityliron ; complex compounds ; crystal structures ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Chemistry of Dimesityl Iron. IX. Diaryl-Iron Complexes with Coordination Number Three and Four: Crystal Structures of [FeMes2(col)] and [FeTrip2(py)2]The diaryliron compounds FeMes2, 1, and FeTrip2, 2, from complexes with coordination numbers (CN) of four, normally. Bulky ligands however give adducts with CN of three. The crystal structures of compounds [1(col)] (CN 3) and [2(py2)] (CN 4) have been determined.
    Notes: FeMes2, 1, und FeTrip2, 2, bilden Komplexe der Koordinationszahl (KZ) vier. Mit großvolumigen Liganden wird jedoch nur ein Donor angelagert. Die Kristallstrukturen von [1(col)] (KZ 3) und [2(py)2] (KZ 4) werden mitgeteilt.
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  • 6
    ISSN: 0044-2313
    Keywords: Dimesityl iron ; aryloxide complexes ; diketonate complexes ; crystal structure ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Chemistry of Dimesityl Iron. X. Mesityl Iron Complexes [FeMes(X)]2 with a Central {Fe2(μ-Mes)2} Unit (Mes = C6H2-2,4,6-(CH3)3)Dimeric complexes [{MesFe(OAryl)}2] with coordination number (CN) of 3 are obtained from Fe2Mes4 1 by partial acidolyses with 2,6-di-tert-butyl-substituted phenols (HOAryl). 1 reacts with 1,3-diketones in a molar ratio of 1:2 to [{MesFe(diketonate)}2] with CN 4. A central {Fe2(μ-Mes)2}-unit with short Fe - Fe distances of 2.56 to 2.63 Å (1: 2.615 Å) is found in both types of complexes. The mixed ligand complexes react with an excess of phenol or diketone to {Fe(OAryl)2} or {Fe(diketonate)2}, respectively. 1 reacts with HOAryl in the molar ratio of 1:1 to [Fe2(μ-Mes)2Mes(OAryl)]. The structures of [Fe2(μ-Mes)2(OC6H2-2,6-tBu2-4-CH3)2] (3), [Fe2(μ-Mes)2Mes(OC6H2-2,4,6-tBu3)] (5) and [Fe2(μ-Mes)2{(tBuCO)2CH}2] (9) are presented.
    Notes: Durch partielle Acidolyse von Fe2Mes4 1, mit 2,6-di-tert-butyl-substituierten Phenolen gelangt man zu dimeren Komplexen [{MesFe(OAryl)}2] der Koordinationszahl drei am Fe-Atom. Setzt man 1 mit 1,3-Diketonen ebenfalls im Verhältnis 1:2 um, entstehen die Verbindungen [{MesFe(diketonat)}2] mit Koordinationszahl vier. In beiden Komplextypen liegt eine zentrale {Fe2(μ-Mes)2}-Einheit mit kurzen Fe - Fe-Abständen von 2,56 bis 2,63 Å vor (1: 2,615 Å). Bricht man die Reaktion von 1 mit HO-Aryl bei einem Molverhältnis 1:1 ab, lassen sich die Primärprodukte [Fe2(μ-Mes)2Mes(OAryl)] isolieren. Die Gemischtligandenkomplexe können zu {Fe(OAryl)2} bzw. {Fe(diketonat)2} weiterreagieren. Die Strukturen von [Fe2(μ-Mes)2(OC6H2-2,6-tBu2-4-CH3)2] (3), [Fe2(μ-Mes)2Mes(OC6H2-2,4,6-tBu3)] (5) und [Fe2(μ-Mes)2{(tBuCO)2CH}2] (9) werden mitgeteilt.
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  • 7
    ISSN: 0044-2313
    Keywords: Organo molybdenum compounds ; oxo complexes ; crystal structure ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Mesityl Oxo Molybdenum and Tungsten Compounds. I. Structure of LiMoO2Me2Mes(OEt2)2LiMoO2Me2Mes(OEt2)2 2 is prepared by literature method [2] from MoO2Mes2 1 and LiMe. Its x-ray structure and NMR-spectral data are presented. 2 adopts a dimer structure in which two [MoO2Me2Mes]- anions are linked via two bridging [Li(OEt2)2]+ cations bonded to the oxo ligands. The resulting [‥OMoOLi‥]2 ring is planar.
    Notes: Die Struktur der bekannten, aus MoO2Mes2 1 und LiMe dargestellten Verbindung LiMoO2Me2Mes(OEt2)2 2 [2] sowie ihre NMR-spektroskopischen Daten werden mitgeteilt. 2 bildet ein in der Raumgruppe P1 kristallisierendes Dimer durch Verknüpfung zweier [MoO2Me2Mes]--Anionen über Oxo-Liganden durch zwei Kationen [Li(OEt2)2]+. Der gebildete [‥OMoOLi‥]2- Achtring ist eben.
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  • 8
    ISSN: 0044-2313
    Keywords: Pt-complexes ; mass spectrometry ; X-ray ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Mass Spectrometric and X-Ray Studies on Complexes of the Type (COD)PtX2 (X = Cl, Br, I, CH3, CH2CMe3, CH2SiMe3)Investigations by mass spectrometry at complexes of the type (COD)PtX2 (X = Cl (1), Br (2), I (3), Me (4), CH2CMe3 (5) and CH2SiMe3 (6), (COD) = 1,5-cyclooctadiene) show the mole peak of all compounds with the characteristic isotopic pattern of platinum and platinum with chlorine, bromine or silicon respectively. The group of peaks of the complexes 1-5 at 300 m/e show a high stability of the (COD)Pt fragment.A new route of synthesis of (COD)PtBr2 (2) is described.The compounds (COD)Pt(CH2CMe3)2 (5) and (COD)Pt(CH2SiMe2 (6) were characterized by X-ray structure.
    Notes: Bei massenspektrometrischen Untersuchungen an Komplexen des Typs (COD)PtX2 X = Cl (1), Br (2), I (3), Me (4), CH2CMe3 (5) und CH2SiMe3 (6), (COD) = 1,5-Cyclooctadien) werden von allen Verbindungen der Molpeak mit dem charakteristischen Isotopenmuster des Platins bzw. des Platins mit Chlor, Brom oder Silicium gefunden. Die beobachteten Peakgruppen der Verbindungen 1-5 bei 300 m/c deuten auf eine hohe Stabilität des (COD)Pt-Fragmentes hin. Ein neuer Syntheseweg zur Darstellung von (COD)PtBr2 (2) wird beschrieben. Die Verbindungen (COD)Pt(CH2CMe3)2 (5) und (COD)Pt(CH2SiMe3)2 (6) wurden röntgenstrukturanalytisch untersucht.
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  • 9
    ISSN: 0044-2313
    Keywords: Dimesityliron ; crystal structure ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Chemistry of Dimesityl Iron. VIII Solution Behaviour of Tetramesityldiiron and Crystal Structure of Dimesityl(dimethoxyethane)ironThe dimer dimesityliron yields in polar solvents solvated monomers. The adduct with dimethoxyethane was isolated and characterized by X-ray structure determination.
    Notes: Während Dimesityleisen in unpolaren Lösungsmitteln dimer vorliegt, spaltet es in stärker polaren Lösungsmitteln in solvatisierte Monomere auf. Mit Dimethoxyethan wurde ein Addukt isoliert und strukturell charakterisiert.
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  • 10
    ISSN: 0044-2313
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Control of the Dimerization of the Cobalt(II) Chelates (N-Ligand)Co(acac)2 by the Amine LigandBesides the trans-octahedral cis-adduct (Ampy)2Co(acac)2, bis(acetylacetonato)cobalt(II) forms the mono-adduct (Ampy)Co(acac)2 (II). In the solid state tetragonal-pyramidal molecules of II are dimerized by intermolecular hydrogen-bonds. 2-Pyridinamine is coordinated by the endo-nitrogen in an apical position. By the short Co—Nendo-bond (2.104 Å) 2-pyridinamine proves as an n- and a π-donor. Therefore the coordination center of II is extensively saturated and a dimerization, comparable to that of (CyNH2)Co(acac)2 (Cy = cyclohexyl) and (py)Co(acac)2, which is connected with an increase of the coordination number (5 → 6), is not observed.
    Notes: 2-Pyridinamin (Ampy) bildet mit Bisacetylacetonato-cobalt(II) neben dem trans-oktaedrischen Bis-Addukt (Ampy)2Co(acac)2 auch ein Mono-Addukt (Ampy)Co(acac)2 (II). Im Kristallgitter von II liegen tetragonal-pyramidale Moleküle vor, die über intermolekulare Wasserstoffbrücken zu Dimeren zusammentreten. 2-Pyridinamin koordiniert mit dem endo-Stickstoff in apicaler Position. Der kurze Co—Nendo-Abstand (2,104 Å) weist 2-Pyridinamin als n- und π-Donator aus. Dadurch wird eine weitgehende Absättigung des Koordinationszentrums von II erreicht. Eine Dimerisierung unter Erhöhung der Koordinationszahl auf 6, wie sie bei (CyNH2)Co(acac)2 und (py)Co(acac)2 eintritt, bleibt daher aus. Nur als n-Donator fungiert 2-Pyridinamin im Komplex (Ampy)2Co(acac)2 (Co—Nendo) = 2,203 Å).
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