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  • Articles: DFG German National Licenses  (14)
  • 2000-2004  (1)
  • 1990-1994  (13)
  • 2001  (1)
  • 1991  (13)
  • 1
    Electronic Resource
    Electronic Resource
    A triptycene complex of tin(II): [(C20H14)SnCl(AlCl4)]2 (1991)
    s.l. : American Chemical Society
    Organometallics 10 (1991), S. 3176-3179 
    Details
    ISSN: 1520-6041
    Source: ACS Legacy Archives
    Topics: Chemistry and Pharmacology
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1021/om00055a037
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  • 2
    Electronic Resource
    Electronic Resource
    Supramolecular chemistry Going for gold (2001)
    [s.l.] : Nature Publishing Group
    Nature 413 (2001), S. 31-33 
    Details
    ISSN: 1476-4687
    Source: Nature Archives 1869 - 2009
    Topics: Biology , Chemistry and Pharmacology , Medicine , Natural Sciences in General , Physics
    Notes: [Auszug] When gold forms a bond with another atom, it simply has to donate one electron to attain an extremely stable electronic state. Conventional wisdom says that atoms in such a state should not engage in any further external bonding. But accumulating experimental evidence and state-of-the-art ...
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1038/35092657
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  • 3
    Electronic Resource
    Electronic Resource
    Arsen(III)-, Antimon(III)- und Bismuth(III)-halogenid-Komplexe des [2.2.2]Paracyclophans: Vom lockeren van-der-Waals-Addukt zu stark gerichteten π-Komplexen mit zwei- und dreifacher externer η6-Koordination (1991)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 124 (1991), S. 1089-1093 
    Details
    ISSN: 0009-2940
    Keywords: [2.2.2]Paracyclophane ligand ; (η6)π Complexes ; Arsenic(III) complexes ; Antimony(III) complexes ; Bismuth(III) complexes ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Arsenic(III), Antimony(III), and Bismuth(III) Trihalide Complexes of [2.2.2]Paracyclophane: From Weak van der Waals Coordination to Strongly Directional π Complexation with Single or Double External η6 Coordination[2.2.2]Paracyclophane forms the adducts C24H24·AsCl3 (1), C24H24·(SbCl3)2·1/2 C6H6 (2), and C24H24·(BiCl3)3·C6H6 (3). For solutions in polar solvents NMR spectra indicate extensive dissociation and/or fluxionality. In the crystals adduct 1 features a weak addition of the AsCl3 molecule to one open side of a paracyclophane molecule with long intermolecular contacts approaching C3v symmetry. - Crystalline 2 shows SbCl3 coordination to two of the benzene rings of the hydrocarbon in a quasi-centered η6 mode, while one of the benzene rings remains uncoordinated. Chlorine-bridging between antimony atoms leads to tetrameric units (SbCI3)4 in the lattice. - In the bismuth compound 3 each benzene ring of the hydrocarbon is engaged in centroid (η6)π complexation, with the BiCl3 units crosslinked by chlorine bridges. The average of the Bi-ring distances (3.08,2.98, and 2.99 Å) is shorter than for the Sb-ring distances in 2 (3.047 and 3.050 Å), indicating stronger bonding. The crystal benzene is not coordinating.
    Additional Material: 3 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19911240516
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  • 4
    Electronic Resource
    Electronic Resource
    Molecular Structure of Trisilylmethane and Synthesis of 1,1,1-Trisilylethane (1991)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 124 (1991), S. 1953-1956 
    Details
    ISSN: 0009-2940
    Keywords: Trisilylmethane ; 1,1,1-Trisilylethane ; CVD feedstock gases ; Silicon carbide, hydrogenated, amorphous (a-SiC:H) ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: As a precursor for trisilylmethane, tris(phenylsilyl)methane is prepared by a Merker-Scott reaction of chlorophenylsilane, bromoform, and magnesium turnings in boiling tetrahydrofuran. Chlorophenylsilane is formed in a new synthesis starting from phenylsilane and hydrogen choride/AlCl3 in diethyl ether. The gas phase structure of trisilylmethane (H3Si)3CH, obtained from (PhSiH2)3CH via (BrSiH2)3CH, has been determined by electron diffraction. Data refinement confirmed a model of C3 molecular symmetry, with local C3v symmetry for the silyl groups.  -  As a precursor for 1,1,1-trisilylethane, 1,1,1-tris(phenylsilyl)ethane has been prepared similarly from chlorophenylsilane, 1,1,1-trichloroethane and magnesium and converted via 1,1,1-tris(bromosilyl)ethane into CH3C(SiH3)3.
    Additional Material: 3 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19911240911
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  • 5
    Electronic Resource
    Electronic Resource
    Metal Bonding by Amino Acids: Preparation and Crystal Structures of Calcium Bis-L-pyroglutamate and Lithium L-Pyroglutamate (1991)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 124 (1991), S. 1083-1087 
    Details
    ISSN: 0009-2940
    Keywords: Calcium bis-L-pyroglutamate ; Lithium L-pyroglutamate ; Pyroglutamate coordination and conformation ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Calcium bis-L-pyroglutamate and lithium L-pyroglutamate are prepared by reaction of the metal hydroxides with L-pyroglutamic acid in aqueous solution. In the solid state calcium bis-L-pyroglutamate adopts a layer structure, built up by sixteen-membered rings consisting of four L-pyroglutamate ligands bridging four calcium centers by their carboxylate groups. All three oxygen donors of the L-pyroglutamate ligands are attached to metal centers. The calcium atom lies at the center of a slightly distorted octahedron formed by four carboxylate oxygens and two amide oxygen atoms. Lithium L-pyroglutamate also features a layer structure. All three oxygen donors of the L-pyroglutamate ligand have contacts with metal atoms. The coordination sphere of the lithium atom is a slightly distorted tetrahedron consisting of three carboxylate oxygen atoms and one amide oxygen atom. The investigation of aqueous solutions of the compounds by multinuclear NMR (1H, 13C, 17O) indicates extensive electrolytic dissociation in dilute solutions.
    Additional Material: 3 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19911240515
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  • 6
    Electronic Resource
    Electronic Resource
    Syntheses and Molecular Structures of an Isoelectronic Series of (2-Hetero-)1,3-Diphosphabenzenes (1991)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 124 (1991), S. 1525-1530 
    Details
    ISSN: 0009-2940
    Keywords: 1,3-Diphosphabenzene derivatives ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Syntheses, NMR spectra, and X-ray molecular structures of three (2-hetero-)1,3-diphosphabenzenes are reported which constitute an isoelectronic triade of compounds with BH2, CH, and N bridging units between the two phosphorus atoms. The remaining three carbon atoms of the rings are part of a 2-methallylic system. The 2-borataheterocycle 3 has been prepared by the reaction of CH2 = C(CH2)PPh2)2 (1) with Me2S—BH2Br to give an intermediate 2 still containing the exocyclic olefinic bond. Treatment of 2 with a base, deprotonation of one ring CH2 group, and proton migration from the other one to the olefinic CH2 group afford the 5-methyl-1λ5-phospha-3-phosphonia-2-boratabenzene 3. The PBP unit is tilted by 144.0(2)° against the planar C3P2 part of the ring. A heterocyclic precursor 4 for the carbon analog is generated from 1 and CH2I2, which on reaction with a strong base yields the diphosphabenzene 5 with a fully planar ring skeleton. For the synthesis of the aza analog 7, CH2=C(CH2Cl)2 is treated with HN(PPh2)2 to give the precursor 6, which can be deprotonatad at nitrogen and carbon with a base. In the crystals of 7, two independent molecules of very similar structure are present. The molecules show planar heterocycles.
    Additional Material: 3 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19911240708
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  • 7
    Electronic Resource
    Electronic Resource
    Metal Ion Binding by Dipeptides: Structure of the Product Generated in “Aspartame” Hydrolysis, Sodium cyclo(L-α-Aspartyl-L-phenylalanine) Tetrahydrate, Na[c(L-Asp-L-Phe)] 4H2O (1991)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 124 (1991), S. 2743-2746 
    Details
    ISSN: 0009-2940
    Keywords: L-α-Aspartyl-L-phenylalanine, cyclisation of ; Dipeptides, cyclic ; Metal complexation by cyclic dipeptides ; Hydrogen bonding ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Ester cleavage of aspartame (L-α-aspartyl-L-phenylalanine methyl ester, 1) by equimolar quantities of NaOH is accompanied by intramolecular cyclisation to sodium 3-benzyl-6-(carboxylatomethyl)-2,5-dioxopiperazine (2). The solid-state structure of the crystalline tetrahydrate has been determined by single-crystal X-ray diffraction analysis. The cations are arranged in strings, and each sodium atom is in a distorted octahedral environment of six oxygen atoms, including a β-carboxylato (O1) and an oxo function (O4) of two different dioxopiperazines and four water molecules. No nitrogen coordination is observed. Through the ligand bridging (O1, O4) of the metals and a set of hydrogen bonds involving the amide and carboxylate groups and all water molecules a three-dimensional network is established.
    Additional Material: 2 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19911241216
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  • 8
    Electronic Resource
    Electronic Resource
    Orotate Complexes, II1) Preparation and Crystal Structures of Calcium and Zinc Orotate(2-) Hydrates (1991)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 124 (1991), S. 2739-2742 
    Details
    ISSN: 0009-2940
    Keywords: Orotate complexes ; Calcium complexes ; Zinc complexes ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: From aqueous solutions containing orotate (dianion of 1) and calcium or zinc ions in the molar ratio of 2:1, metal orotate (2-) hydrates are readily obtained in crystalline form at pH 9.0 and 5.4, respectively. According to an X-ray crystal structure analysis, calcium orotate tetrahydrate forms a one-dimensional coordination polymer with each orotate ligand coordinated to no less than three neighboring calcium atoms. In this cation triple, the orotate(2-) anion acts as a carboxylate-O/amide-N-chelating group for the central calcium ion, but also as a carboxylate-O/O-chelating group for the first neighboring calcium ion, and as a terminal amide-O donor for the second. Each calcium ion is thus octacoordinated and linked to three orotate(2-) anions and three water molecules. The fourth water molecule is only engaged in hydrogen bonding. The new zinc orotate(2-) phase features Zn(Or)(H2O)4 units. For the hexacoordinate zinc atom bearing four water molecules the orotate(2-) ligand also acts as an O/N-chelating group. Unlike a discrete Zn(Or)(H2O)4 H2O phase reported earlier, the lattice of the new phase contains further disordered water of crystallization, with the overall composition approaching Zn(Or) 5.5 H2O. The apparent stability of the M(Or) units probably reflects the well-documented carrier function of the orotate ligand for certain divalent metal ions in biological systems.
    Additional Material: 2 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19911241215
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  • 9
    Electronic Resource
    Electronic Resource
    Phosphane-Borane Chemistry. - Borane Adducts of Two Polyfunctional Phosphanes (1991)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 124 (1991), S. 275-278 
    Details
    ISSN: 0009-2940
    Keywords: Phosphane-borane adducts ; Diphosphinomethane ; Tripodal phosphane ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The tris(borane) adduct MeC(CH2PMe2BH3)3 (2) of 1,1,1-tris-[(dimethylphosphino)methyl]ethane has been prepared from the tripodal phosphane and Me2S-BH3 as the borane source. The crystal structure of 2·1/2 toluene has been determined by single-crystal X-ray diffraction methods. The molecules display crystallographic C3 symmetry and an overall staggered conformation. In an analogous way the bis(borane) adduct CH2(PH2BH3)2 (3) of 1,3-diphosphapropane has been synthesized, which decomposes above 50°C to give insoluble products, whose elemental analysis indicated that termal P-C bond cleavage is more frequent than P-B bond cleavage.
    Additional Material: 2 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19911240206
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  • 10
    Electronic Resource
    Electronic Resource
    Synthesis and Structural Aspects of Phosphane - Boranes Derived from Tris(diphenylphosphino)methane, HC(PPh2)3 (1991)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 124 (1991), S. 1095-1100 
    Details
    ISSN: 0009-2940
    Keywords: Trisphosphanes ; Phosphane - boranes ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The structure of tris(diphenylphosphino)methane, HC(PPh2)3 (1), has been determined by X-ray diffraction. The molecules have approximate C3 symmetry with the lone pairs at the three phosphorus atoms in an “all-trans” orientation. Variable-temperature NMR experiments (+ 35 to - 90°C in CH2Cl2) show free intramolecular motion in solution. The partially or fully borylated adducts HC(PPh2)2[PPh2(BH3)] (2), HC(PPh2)[PPh2;-(BH3)]2 (3), and HC[PPh2(BH3)]3 (4) have been prepared from 1 and THF · BH3 or Me2S · BH3. For 2 and 3 the internal rotation about the phosphorus-methine carbon bonds is also essentially unhindered, but has been shown to be restricted in 4 (Ea=31.2 kJ/mol). The chemical shifts of the methine protons in these compounds can be calculated on the basis of a BH3 substituent constant.
    Additional Material: 3 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19911240517
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