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  • Inorganic Chemistry  (1,306)
  • Life and Medical Sciences  (1,204)
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  • 1996  (1,668)
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  • 1980-1984  (1,739)
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  • 1
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 129 (1996) 
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
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  • 2
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 129 (1996), S. 11-13 
    ISSN: 0009-2940
    Keywords: Triferriophosphane sulfide ; Metallothioxophosphorane ; PS complex ; Spiro compounds ; Decarbonylation ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The P-H-functional triferriophosphonium salts [{CpFe-(CO)2}3PH]2FeCl4 (1) and [{μ-CO(CpFeCO)2}{CpFe-(CO)2}PH]2FeCl4 (4) are easily deprotonated by DBU to the corresponding unstable triferriophosphanes 2, 5, which subsequently are oxidized by sulfur to the triferriophosphane sulfides {CpFe(CO)2}3P=S (3) and {μ-CO(CpFeCO)2}{CpFe-(CO)2}P=S (6), respectively. The photolysis of 3 results only in its decomposition by elimination of [CpFe(CO)2]2, whereas the photolysis of 6 cleaves off one CO ligand to give the new spiro compound (CpFeCO)(μ-η2-PS){μ-CO(CpFeCO)2} (7), where the P=S unit is η2-bonded to the 15-electron CpFeCO fragment, and the phosphorus atom bridges two 17-electron fragments. Compound 7 shows a new coordination mode of the PS unit where sulfur is also bound to one of the metal atoms. Compounds 6 and 7 can be regarded as first examples of a new class of PS complexes of transition metals. All compounds were characterized by IR, 31P{1H}- and 13C{1H}-NMR spectroscopy as well as mass spectrometry; for 6 the X-ray analytical data are given.
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  • 3
    ISSN: 0009-2940
    Keywords: Triazacyclohexanes ; Chromium complexes ; Amides ; Hexamethyldisilane ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The reaction of N,N′,N′′-trimethyl-1,3,5-triazacyclohexane chromium trichloride ((Me3TAC)CrCl3, 1) with LiN(SiMe3)2 or NaN(SiMe3)2 in petroleum ether yields nearly quantitatively [Cr{N(SiMe3)2}3] (2) with loss of the Me3TAC ligand. Compound 2 could be crystallized from hexamethyldisilane as [Cr{N(SiMe3)2}3] · (Me6Si2)0,5 which allowed the refinement of the X-ray crystal structure in the trigonal space group P-31c (no. 163) (a = 16.012(3) Å, c = 8.4796(12) Å, V = 1882.8(6) Å3, Z = 2) without severe disorder.
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  • 4
    ISSN: 0009-2940
    Keywords: Glyceraldehyde ; Ligands, tridentate ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: A series of seven chiral, tripodal N,O,S and N,N,O ligands were prepared in which N stands for a secondary amine or imidazole donor, O for a phenol, and S for a thioether or thiol metal-binding group. Key steps are (1) the construction of ortho-hydroxyacetophenones bearing the phenolic binding group and either a thioether, a protected thiol or an imidazole substituent in the α-position, and (2) subsequent reductive amination with a primary amine. The modular synthesis allows a rapid construction of a variety of structurally related ligands. In three cases, the enantiomers of the racemic products could be separated after condensation with (R)-glyceraldehyde acetonide as chiral auxiliary. The relative configurations of the cyclic N,O- and N,N-acetals thus obtained were established by NOE spectroscopy. X-ray structural analysis of two crystalline N,O- and N,N-acetals allowed the assignment of absolute configurations. Hydrolysis of the dia-stereomerically pure acetals afforded the enantiomerically pure ligands in high yield. By comparison of their CD spectra, absolute configuration could also be assigned to the third pair of enantiomerically pure ligands.
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  • 5
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 129 (1996), S. 85-89 
    ISSN: 0009-2940
    Keywords: Rhodium complexes, chiral ; Hydrogenation ; Bisolefins ; Thermodynamic stability ; Kinetic control ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Asymmetric hydrogenations of prochiral olefines by means of chiral rhodium(I) complexes of the type [Rh(L)(PP*)]A (L = COD, [(Z,Z)-cycloocta-1,5-diene], or NBD (norborna-2;5-diene), PP* = chiral bisphosphane forming seven-membered chelate rings, A = anion like BF4-) are often associated with induction periods caused by partial blocking of the catalyst. NBD complexes are hydrogenated faster than the corresponding COD complexes. Catalytic hydrogenation of COD/NBD mixtures and the determination of the ratio of the Michaelis constants showed that the steady-state concentration of the COD complex under hydrogen is higher than that of the NBD complex. However, under argon the NBD complex predominates owing to its higher thermodynamic stability compared with that of the COD complex as determined by 31P-NMR spectoscopy. This complete reversion of the ther-modynamically determined ratios of COD to NBD complex concentration under hydrogenation conditions was proven by means of UV/Vis spectroscopy.
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  • 6
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 129 (1996), S. 233-235 
    ISSN: 0009-2940
    Keywords: Positional selectivity ; Bromination ; Halogen/lithium exchange ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: 1-Bromo-3,5-bis(trifluoromethyl)benzene (1) can be selectively prepared by treatment of 1,3-bis(fluoromethyl)benzene with N,N'-dibromo-5,5-dimethylhydantoin in strongly acidic media. A number of synthetically useful reactions via 3,5-bis(trifluoromethyl)phenylmagnesium, -lithium, and -copper intermediates were accomplished.
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  • 7
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 129 (1996), S. 253-257 
    ISSN: 0009-2940
    Keywords: Lithiated phosphane imines ; Phosphane imines, lithiated ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Lithiated Phosphane Imines. Synthesis and Crystal Structures of [LiCH2PMe2NSiMe3]4 and [LiCMe2P(iPr)2NSiMe3]2The title compounds were prepared by the reaction of Me3-SiNPMe3 and Me3SiNP(iPr)3, respectively, with n-Butylli-thium at 20°C in n-hexane solution. They form white, moisture- and oxygen-sensitive crystals, which were characterized by IR spectroscopy and by crystal structure determinations. - [LiCH2PMe2NSiMe3]4 (1) forms a Li4 tetrahedron, the faces of which are capped with CH2 groups with average Li-C distances of 233 and 251 pm, while the nitrogen atoms occupy the corners of the Li4 tetrahedron. - [LiCMe2P(iPr)2N-SiMe3]2 (2) forms molecules of symmetry C2 in which the lithium atoms have coordination number three by two carbon atoms and one nitrogen atom with Li-C distances of 215.2 and 237.9 pm and Li-N of 192.8 pm.
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  • 8
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 129 (1996), S. 269-273 
    ISSN: 0009-2940
    Keywords: Organometallic polymers ; Coupling reactions ; Butadiynyl complexes ; Cobalt compounds ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The synthesis of 3a starting from compound 1 is described. Copper-catalyzed oxidative coupling of 3b under Hay conditions gives the novel polymer 9 with octatetrayne-cyclobutadiene units.
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  • 9
    ISSN: 0009-2940
    Keywords: Bis[2.2]metacyclophanes ; Stilbenes ; π-π Interaction ; Tricarbonylchromium complexes ; Charge-transfer ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: (E)-8,8′-(Ethene-1,2-diyl)bis(5-tert-butyl[2.2]metacyclo-phane) (2) was obtained from a McMurry reaction of 5-tert-butyl-8-formyl[2.2]metacyclophane (1). Irradiation of 2 with a high-pressure mercury lamp gave the corresponding (Z) isomer 3. X-ray crystallographic analyses of 2 and 3 show a certain degree of twisting of the bond connecting the meta-cyclophane unit and the central π system due to steric crowding. UV spectra of 2 and 3 and of the charge-transfer complexes [2/TCNE] and [3/TCNE] allow for a discussion of π-π interaction between the central stilbene subunit and the outer benzene rings of the metacyclophane units. Bis[2.2]meta-cyclophanes 2 and 3 reacted regioselectively with hexacar-bonylchromium on the outer benzene rings giving 1:1 and 1:2 complexes 9-14 with tricarbonylchromium. No 1:3 and 1:4 complexes formed due to steric restrictions. Analysis of UV spectral data of the complexed [2.2]metacyclophanes was performed for an indication of π-π interactions in the complexes.
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  • 10
    Electronic Resource
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    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 129 (1996), S. 283-287 
    ISSN: 0009-2940
    Keywords: Self-assembling frameworks ; Thermal stability ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Here we report on investigations that have revealed for the first time that the Cs+ ion templates the same metal germanium sulfide open-framework as (CH3)4N+ (TMA+), and that metal complexing agents enhance crystal size by at least two orders of magnitude. The synthesis, structures and thermal properties of Cs2FeGe4S10 ·× H2O and TMA2FeGe4S10 are also described. Both have 3D zinc blende-type open-framework structures. These materials have the same connectivity as TMA2MnGe4S10. The tetrahedral sites in the lattice are alternately substituted by pseudo-tetrahedral Fe2+ and adamantanoid Ge4S104- building blocks, covalently linked together by Fe(μ-S)Ge bridge bonds, to give a tetragonal unit cell. The charge-balance of the anionic framework [Fe-Ge4S10]2- is maintained by either Cs+ or TMA+ ions in the cavity spaces. Synthesis of these materials demonstrates an interesting example of a self-assembly process in which a 3D framework is built from molecular precursors. Water adsorption-desorption cycling from room temperature to 200 °C reveals framework flexibility between larger and smaller tetragonal unit cell 14 isotypes. The compound TMA2FeGe4S10 is stable in nitrogen at 350 °C and under vacuum at 450 °C. The corresponding temperatures for Cs2FeGe4S10 are 530 °C and 630°C; it is stable on cooling to room temperature under vacuum, and after subsequent exposure to air. Six hundred thirty degrees celsius is the highest recorded temperature at which the integrity of a non-oxide framework has been maintained. The framework stability and flexibility of “all-inorganic” Cs2FeGe4S10 provides an encouraging example for researchers interested in developing sulfide-based framework materials with practical applications.
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  • 11
    ISSN: 0009-2940
    Keywords: Gold complexes ; Silver complexes ; Palladium complexes ; S-Donor ; Thiones ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: AgClO4 reacts with bidentate ligands 2-(methylthio)pyridine (SMepy) or complexes PPN[Au(Spy)2] [PPN = N(PPh3)2, HSpy = pyridine-2(1H)-thione) or PPN[Au(Sbz)2] (HSbz = benzoxazole-2(3H)-thione), themselves acting as ligands, to give dinuclear complexes [Ag2(μ-SMepy)2](ClO4)2 (1), [AgAu(μ-Spy)2] (2), or [AgAu(μ-Sbz)2] (3), respectively. By treating 1 with [AuCl(tht)] (tht = tetrahydrothiophene), [Au(SMepy)(tht)]ClO4 (4) is obtained which, in turn, reacts with SMepy to give [Au(SMepy)2]ClO4 (5). Similarly, [PdCl2(NCPh)2] reacts with SMepy in 1:1 molar ratio to give [Pd2Cl2(μ-Cl)2(SMepy)2] (6) which reacts with SMepy in 1:2 molar ratio to give [PdCl2(SMepy)2] (7). On the other hand, HSpy reacts with Ag2CO3 to give [Ag2(μ-Spy)2] (8), and (SMepyH)ClO4 reacts with [Au(acac)PPh3] (acacH = acetyl-acetone) to give [Au(SMepy)PPh3]ClO4 (9).
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  • 12
    ISSN: 0009-2940
    Keywords: Histidine peptides ; Zinc complexes ; EXAFS analysis ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: One tripeptide, five tetrapeptides, and one pentapeptide, all containing His-Xn-His sequences and being blocked at the N and C termini with acyl and amide functions, respectively, were synthesized by solid-phase methods. With one exception their reaction with various zinc salts led to the precipitation of 1:1 (zinc/peptide) complexes. Analytically pure compounds were obtained from zinc tetrafluoroborate and His-Gly-His (1), from zinc chloride (resp. bromide) and His-Gly -Gly-His (2), His-Ala-Gly-His (3), His-Leu-Gly-His (4), His-Pro-Gly-His (5), and His-Pro-Asn-His (6) as well as from zinc sulfate and His-Leu-Gly-His (4) and His-Ala-Pro-Gly-His (7). 1H-NMR data, when available, indicate the coordination of both histidine units to zinc in all cases. The low solubility of the complexes points to their polymeric nature. The only 1:2 (zinc/peptide) complex in this series was obtained from zinc perchlorate and His-Gly-Gly-His (2). An EXAFS study revealed that it contains zinc symmetrically coordinated by four histidine imidazole ligands. Based on the available information it is proposed that all complexes are one-dimensional polymers containg [-Zn-His-Xn-His-Zn-]x backbones.
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  • 13
    Electronic Resource
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    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 129 (1996) 
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
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  • 14
    ISSN: 0009-2940
    Keywords: Silanediols ; Silanetriols ; Siloxanes ; Hydrogen bonding ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The silanediols RN(SiMe3)Si(OSiMe3)(OH)2 (R = 2,4,6-Me3C6H2 4, 2,6-Me2C6H3 5, and 2,6-iPr2C6H3 6) were prepared by the reactions of the respective silanetriols RN(SiMe3)-Si(OH)3 1 - 3 with SiMe3Cl in THF/hexane. Silanetriol 1 in CH2Cl2/hexane solution converts over a period of 4 weeks into the silanediol (2,4,6-Me3C6H2)N(SiMe3)Si(OSiMe2 R)-(OH)2 [R = CH2(2-NH2-3,5-Me2C6H2)] (7). Compounds 4 - 7 were characterized by means of mass, IR and NMR (1H and 29Si) spectroscopy. Additionally, the molecular structures of 4 and 7 were determined by single-crystal X-ray diffraction studies. Compound 4 forms O — H…O hydrogen-bonded tetramers in the solid state. A nine-membered ring formed by an intermolecular O—H…N hydrogen bond is found in the solid-state structure of 7.
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  • 15
    ISSN: 0009-2940
    Keywords: Iridium complexes ; Stibane complexes ; Hydrido complexes ; Ethene complexes ; Ligand displacement reactions ; Alkyne-to-vinylidene rearrangement ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The reaction of [IrCl(C8H14)2]2 (2) with SbiPr3 in the presence of H2 yields the dihydridoiridium(III) complex cis,mer-[IrH2Cl(SbiPr3)3] (3) which on treatment with CO and with HC≡CR (R = Ph, CO2Me) affords the octahedral derivatives [IrH2Cl(CO)(SbiPr3)2] (4) and [IrHCl(C≡CR)(SbiPr3)3] (5, 6), respectively. The stibane ligand trans to hydride in 5 and 6 is rather labile and, therefore, 5 and 6 react with pyridine to give [IrHCl(C≡CR)(py)(SbiPr3)2] (7, 8). Five-coordinate bis-(stibane)iridium(I) complexes [IrCl(C2H4)2(SbR3)2] (10-12) were prepared from [IrCl(C2H4)2]2 (9) and four equiv. of SbR3 (R = iPr, Me, Ph). The X-ray crystal structural analysis of 10 reveals a distorted trigonal-bipyramidal geometry around the metal center with one stibane ligand and the two olefinic ligands in the equatorial plane. Compound 10 reacts with NaC5H5 to yield [C5H5Ir(C2H4)(SbiPr3)] (13) and with different alkynes by partial or complete displacement of the ethene ligands to give trans-[IrCl(PhC≡CPh)(SbiPr3)2] (14), [IrHCl(C≡CTol)(C2H4)(SbiPr3)2] (15), and trans-[IrCl-{=C=C(SiMe3)R}(SbiPr3)2] (16, 17), respectively.
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  • 16
    ISSN: 0009-2940
    Keywords: Azolylborane adducts ; Boron-imidazole adducts ; Boron-pyridine adducts ; Protic-hydric interactions ; Protic-fluoride interactions ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The preparation, NMR and X-ray diffraction studies of a series of azolylboron hydrides derived from pyrrole, indole, and carbazole coordinated with tetrahydrofuran, pyridine, and imidazole are reported. The azolyl substituents are very electroattractive leading to an acidic boron atom which strongly coordinates with the Lewis bases. The stabilization of the =BH2=groups against disproportionation could be explained in terms of the interactions found between the acidic hydrogen atoms of the heterocycles (C=Hδ+ acceptor) and the hydrides (B=Hδ- donors).
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  • 17
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    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 129 (1996) 
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
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  • 18
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    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 129 (1996), S. 485-487 
    ISSN: 0009-2940
    Keywords: Dimetallations ; Insertions ; Rhenium ; Isothiocyanates ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Molecules containing dimetallated hydrocarbyl groupings are of great chemical interest[1-3]. These groupings often represent intermediates in important catalytic processes[4]. Recently, we have shown that substituted dimetallated olefins can be formed by alkyne insertion into the metal-metal bonds of certain dinuclear complexes[2,5]. Complexes having dimetallated hydrocarbyl groups combined with heteroatoms are quite rare[6]. Herein is described the formation of a dimetallathioimidate grouping by the insertion of an organic isothiocyanates into an unsupported metal-metal bond. Organic isothiocyanates are useful reagents in organic synthesis[7], but the organometallic chemistry of these molecules is not yet well developed[8].
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  • 19
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    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 129 (1996), S. 521-525 
    ISSN: 0009-2940
    Keywords: Liquid crystals ; Siloxanes ; Phase behaviors ; Defined topology ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: It is shown that supermolecules with a tetrahedral symmetry and appropriate side-chains exhibit liquid-crystalline phase behaviour. The use of an optimised hydrosylation reaction allows for the synthesis of materials that have four mesogenic groups attached to a siloxane core, where the conformation and the configuration are unambiguous. The materials show low glass transition temperatures and, depending on the spacer length, complex liquid-crystalline morphologies.
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  • 20
    ISSN: 0009-2940
    Keywords: Iron and ruthenium complexes ; Water soluble complexes ; Sulfur ligands ; X-ray structure analyses ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: In search of water soluble transition metal complexes with sulfur dominated coordination spheres that model key reactions of nitrogenases, the benzenedithiol derivatives ‘CO2HS2’-H2 (1) and ‘CO2Me-S2’-H2 (2) were synthesized as precursors for multidentate sulfur ligands. The template alkylation of 2 by C2H4Br2 at [Fe(CO)2] fragments yielded a mixture of two diastereomeric C2 symmetrical [Fe(CO)2(‘CO2Me-S4’)] complexes (4a and 4b), which were separated by crystallization. The hydrolysis of the mixture of the diastereomers 4a and 4b led to the isomerically pure tetradentate thioether thiol ligand ‘CO2Me-S4’-H2 (5) proving the regioselectivity of the template alkylation of the asymmetrical dithiol 2. The C1 symmetrical [Fe(‘CO2Me-S2’)2]2- anion is an intermediate of the template alkylation and was isolated as (AsPh4)2 [Fe(‘CO2Me-S2’2] (11), 4a, 5 and 11 were characterized by X-ray structural analysis. Saponification of the methyl ester groups of 5 yielded ‘CO2H-S4’-H2 (7). Treatment of 7 with FeCl2 · 4 H2O in the presence of CO and LiOMe gave a mixture of two C2 symmetrical and water soluble diastereomers of Li2[Fe(CO)2(‘CO2-S4’)] (8). Upon treatment with [RuCl2 (PPh3)3] 7 yielded isomerically pure [Ru(PPh3)2-(‘CO2H-S4’)] (9). 9 also exhibits C2 symmetry and could be reversibly deprotonated to form the water soluble complex K2[Ru(PPh3)2 (‘CO2-S4’)] (10). Treatment of (NBu4)2 (‘CO2MeS2’) with “Ru(NO)Cl3” led to isomerically pure (NBu4)[Ru(NO)(‘CO2Me-S2’)2] (12).
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  • 21
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    Berichte der deutschen chemischen Gesellschaft 129 (1996), S. 833-836 
    ISSN: 0009-2940
    Keywords: Oxotitanium(IV) porphyrinate ; Peroxotitanium(IV) porphyrinate ; Photochemistry ; Singlet oxygen ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The syntheses of oxotitanium(IV) meso-tetrakis(2,3,4,5,6-pentafluorophenyl)porphyrinate O=Ti(TPPF20) (1), oxotitanium(IV) meso-tetrakis(2,6-difluorophenyl)porphyrinate O=Ti-(TPPF8) (3), and oxotitanium(IV) meso-tetrakis(2,6-dichlorophenyl)porphyrinate O=Ti(TPPCl8) (5) from titanium tetrachloride and the corresponding porphine are described. The structure of 1 was determined by single-crystal X-ray diffraction. The reaction of oxotitanium porphyrinates with aqueous hydrogen peroxide leads to the corresponding light-sensitive peroxotitanium(IV) complexes: Ti(O2)(TPPF20) (2), Ti(O2)-(TPPF8) (4), Ti(O2)(TPPCl8) (6). All complexes are efficient and stable photosensitizers for the generation of singlet oxygen.
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  • 22
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    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 129 (1996), S. 837-839 
    ISSN: 0009-2940
    Keywords: Boron compounds ; Silaboranes ; Dihetero-closo-borane ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Addition of 3 equivalents of KH · BEt3 to [Me3NH][Me-SiB10H12] followed by addition of one equivalent of SnCl2 or SbI3 affords the stanna-sila-closo-borate(1-) 3 and stiba-sila-closo-borane 4, respectively. [MePh3P] · 3 crystallizes in the orthorhombic space group P212121.
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  • 23
    ISSN: 0009-2940
    Keywords: Amides ; Pyrrolyl complexes ; Chelate complexes ; Transition-metal complexes ; Metallacycles ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Intramolecularly Stabilized Metal Amides: 2-(Dimethylaminomethyl)pyrrolyl Complexes of Titanium(III), Vanadium(III), Chromium(III), Cobalt(II) and Nickel(II)By the metallation of 2-(dimethylaminomethyl)pyrrol (HL) with butyllithium the lithium pyrrolide LiL (1) was obtained. The reactions of 1 with TiBr3 · 3 THF, VBr3 · 3 THF, CrBr3 · 3 THF, CoBr2 · 2 THF, and NiBr2 · 1.67 THF result in the formation of the 2-(dimethylaminomethyl)pyrrolyl complexes of type ML3 (2-4), and ML2 (5, 6), respectively. The structures of these new compounds are discussed on the basis of magnetic and visible absorption measurements. An X-ray crystal structure determination of 4 reveals a strongly distorted octahedral environment of the chromium atom with facial arrangement of the ligands.
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  • 24
    ISSN: 0009-2940
    Keywords: Rhodium complexes ; Alkyne complexes ; Insertion reactions ; Alkyl isocyanides ; Metallacycles ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The cyclopentadienyl complexes [C5H5Rh(RC≡CR′)(SbiPr3)] (5-8), which were prepared from trans-[RhCl-(RC≡CR′)(SbiPr3)2] (1-4) and NaC5H5 and which contain a labile Rh-SbiPr3 bond, reacted with CO and CNR″ (R″ = Me, tBu) to give the carbonyl and isocyanide derivatives [C5H5Rh(RC≡CR′)(CO)] (9-11) and [C5H5Rh(RC≡CR′)-(CNR″)] (12-16), respectively. On treatment of 12 (R = R′ = Ph; R″ = Me) with SbiPr3, the metallacyclobutene complex [C5H5Rh{κ2(C,C}-C( = NMe)CPh=CPh}(SbiPr3)] (17) was formed; it reacts with excess CNMe or CNtBu to yield the metallacyclopentenes [C5H5Rh{κ2(C,C)-C(=NMe)CPh=CPhC-(=NR)}(CNR)] (18, 19). Similar compounds 20-23 containing a five-membered RhC4 metallacycle were prepared either from [C5H5Rh(RC≡CR′)(SbiPr3)] (7, 8) or [C5H5Rh-(PhC≡CPh)(CNtBu)] (14) and excess isocyanide. The crystal and molecular structures of 17 and 18 (R = Me) have been determined.
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  • 25
    ISSN: 0009-2940
    Keywords: Phthalocyanines ; Porphyrins ; Lanthanide(III) compounds ; Macrocyclic ligands ; Double-decker complexes ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Treatment of 5,10,15,20-tetra-4-pyridylporphyrin [(TPyP)H2] with europium(III) or gadolinium(III) acetylacetonate [Ln(acac)3 · nH2O] (Ln = Eu, Gd) in 1,2,4-trichlorobenzene produced Ln(acac)(TPyP), which reacted with dilithium phthalocyaninate [Li2(Pc)] to give Li[Ln(Pc)(TPyP)] in moderate yields. Upon exposure to air, solutions of these compounds converted slowly to the corresponding neutral complexes Ln(Pc)(TPyP). The new compounds were spectroscopically characterized.
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  • 26
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    Berichte der deutschen chemischen Gesellschaft 129 (1996), S. 937-944 
    ISSN: 0009-2940
    Keywords: Iron acyl complexes ; (Alkynyl)carbene ligand ; Cationic aminocarbene complexes ; Iron (2-methoxyvinyl)aminocarbene complexes ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: (Alkynoyl)iron complexes 1, Cp(CO)2Fe(O=CC≡CR) (R = CH3, Ph, SiMe3), were synthesized by applying a mixed anhydride procedure and transformed into the cationic methoxycarbene complexes 2, [Cp(CO)2 Fe(C(OMe)C≡CR)+]-[PF6-]. Primary amines H2NR′ react with the methoxycarbene complexes to furnish exclusively cationic aminocarbene complexes 3, [Cp(CO)2 Fe(C(NHR′)C≡CR)+][PF6-], or (2-methoxyvinyl)aminocarbene complexes 5. The spectroscopic properties of the new complexes are discussed. The (alkynyl)-aminocarbene complexes 3e and 3f were characterized by X-ray crystal structure analysis.
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  • 27
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    Berichte der deutschen chemischen Gesellschaft 129 (1996), S. 967-971 
    ISSN: 0009-2940
    Keywords: Phthalocyanines, sulphonated ; Diazadithiamacrocycles ; Pentanuclear complex ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Metal phthalocyanines (M = Cu, Ni, Co) 3-5 bearing four 16-membered diazadithia macrocycles at the peripheral positions were prepared. Detosylation with concentrated sulfuric acid afforded products containing both sulfonated groups on the aromatic rings of the macrocyclic substituents which are excellently soluble in water and donor sites for binding four CuII ions to give a pentanuclear complex.
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  • 28
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    Berichte der deutschen chemischen Gesellschaft 129 (1996), S. 1379-1381 
    ISSN: 0009-2940
    Keywords: Thionitrosyl chloride ; Thiazyl chloride ; Neutralization-reionization mass spectrometry ; Calculations, ab initio ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Ab initio MO calculations at the QCISD(T)/6-311++G(3df,2p) + ZPE level show that the thionitrosyl chloride ion, ClNS+•, is 36 kJ/mol more stable than the thiazyl chloride ion, NSCl+•, whereas neutral NSCl is 77 kJ/mol more stable than ClNS [IEa (ClNS) = 9.2 ± 0.3 eV, IEa (NSCl) = 10.5 ± 0.3 eV]. Mild flash-vacuum pyrolysis of the thiazyl chloride trimer (NSCl)3 followed by electron impact ionization resulted in the formation of [N,S,Cl]+• ions (m/z 81). The fragments observed in the CA spectrum of these ions indicate the formation of both NSCl+• and ClNS+• ions. A very weak recovery signal is observed in a neutralizationreionization experiment. This signal is tentatively assigned to the neutral thionitrosyl chloride.
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  • 29
    ISSN: 0009-2940
    Keywords: Gold ; Mercury ; Nitroaryl ; Transmetallation ; Biaryl ; C-C Coupling ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: 4-Butoxynitrobenzene reacts with [Hg(O2CCF3)2] and LiCl to give [Hg(R)Cl] [R = C6H3NO2-3, OnBu-6 (1)] which is symmetrized by Me4NCl to give [HgR2] (2), the crystal structure of which has been determined. The reaction of 2 with Me4N[AuCl4] affords Me4N[Au(R)Cl3] (3) by a facile transmetallation process. Complex 3 reacts with PPh3 (1:1) to give cis-[Au(R)(PPh3)Cl2] (4). The diaryl complex [-Ph-2)(R)Cl] (5) is obtained by reaction of 3 with [Hg-(C6H4N=NPh-2)2] through a second transmetallation reaction. Complex 5 and PPh3 (1:1) give [AuClPPh3] and the C-C coupling biphenyl RC6H4N=NPh-2 (6).
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  • 30
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    Berichte der deutschen chemischen Gesellschaft 129 (1996), S. 1409-1419 
    ISSN: 0009-2940
    Keywords: Sulfenic acid anions ; Thiosulfinic acid anions ; Thiosulfonic acid anions ; Transition metal complexes ; Stereochemistry ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The synthesis and coordination chemistry of sulfenic, thiosulfinic, and thiosulfonic acid anions are reviewed. Different approaches, which yield the platinum(II) and ruthenium(II) complexes containing the anionic sulfur(0), sulfur(II), and sulfur(IV) oxid ligands, are described. The oxidative addition of thiosulfinates or N-sulfinyl phthalimides to platinum(0) complexes L2Pt(C2H4) [L = PPh3, 1/2 PPh2CH2CH2PPh2, 1/2 (R,R)-(-)-DIOP, 1/2 (C5H4PPh2)Fe(C5H4PPh2) leads to sulfenato complexes; those of N-thiosulfinyl phthalimidies or trisulfid 1-oxides afford the thiosulfinato complexes. Moreover, the reactions of CpRu(PPh3)(L)(SH) (L = CO, PPh3) with N-sulfinyl phthalimides forming the thiosulfinato moiety, are reported. The spectroscopic, structural and chemical properties of these complexes are discussed.
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  • 31
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    Berichte der deutschen chemischen Gesellschaft 129 (1996), S. 1057-1059 
    ISSN: 0009-2940
    Keywords: (Alkynyl)carbene ligands ; Iron acyl complexes ; Cationic iron aminocarbene complexes ; Diels-Alder reactions ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The cationic iron (alkynyl)aminocarbene complexes [Cp(CO)2Fe(C(NHR)C≡CSiMe3][PF6], (R = C6H5, p-CH3C6H4) 1 derived from aromatic amines smoothly react with cyclopentadiene in dichloromethane to yield the cycloadducts 2. No reaction was observed for complexes derived from sterically demanding aliphatic amines, like L-alanine tert-butyl ester. For comparison, the alkynyl-substituted acyl iron compounds Cp(CO)2Fe(C=O)C≡C̊ (R = SiMe3, C6H5) 3 were investigated, requiring TiCl4 catalysis to undergo the cycloaddition reaction. The structures of the cycloadducts 4 were determined by X-ray crystallography.
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  • 32
    ISSN: 0009-2940
    Keywords: Nickel(0) ; Alkyne complexes ; Hydrogen bonds ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Treatment of (cdt)Ni (cdt: cyclododeca-1,5,9-triene) with 2 equivalents of 2-methyl-4-trimethylsilyl-3-butyn-2-ol leads to the selective formation of the homoleptic complex (alkyne)4Ni3 (compound 3), which can be isolated in excellent yields. The solid-state structure of 3 exhibits three Ni centers, forming a bent Ni3 chain connected by two bridging alkynes. The other two alkynes are terminally coordinated. Additionally, the trimeric units are stabilized by three intramolecular hydrogen bonds. Two intermolecular hydrogen bonds connect the trimeric units to form a polymer rope. According to the 13C- and 1H-NMR spectra in THF the structure of the complex 3 in solution is very similar to that in the solid state. The reaction of 3 with some alkynediols and with 2,5,5-trimethylhex-3-yn-2-ol affords compounds of the type (alkyne)2Ni. Cot (cot: 1,3,5,7-cyclooctatetraene) converts 3 into [(cot)Ni]2, which in turn reacts with 2,5-dimethylhex-3-yne-2,5-diol to form the dimeric complex (alkyne)2Ni2(cot) 6. X-ray analysis of 6 reveals a very symmetrical structure in which cot connects both Ni(0) centers at opposite sides of the ring system.
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  • 33
    ISSN: 0009-2940
    Keywords: Sulfur dioxide ; Rhodium complexes ; Ether-phosphanes ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The SO2 coordination mode at the rhodium complex [ClRh(P∼O)()] (1) [ = η2(O,P)-chelated Cy2PCH2CH2OCH3 ligand; P∼O = =1(P)-coordinated] is controlled by the hemilabile ligand Cy2PCH2CH2OCH3 and shows a dependence on the polarity of the solvent. In polar organic solvents (e.g. acetone) the addition of sulfur dioxide results in the formation of a trigonal-pyramidal oriented SO2 group in [ClRh(η1-SO2)(P∼O)()] (2a). However, in nonpolar media (e.g. n-hexane) a trigonal-coplanar geometry of the SO2 unit in [ClRh(η1-SO2)(P∼O)2] (2b) is favored.
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  • 34
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    Berichte der deutschen chemischen Gesellschaft 129 (1996) 
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    Keywords: Chemistry ; Inorganic Chemistry
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  • 35
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    Berichte der deutschen chemischen Gesellschaft 129 (1996), S. 1475-1482 
    ISSN: 0009-2940
    Keywords: Allenylidene complexes ; Alkynyl complexes ; Cyclobutenylidene complexes ; Cycloadditions ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Pentacarbonyl(allenylidene)chromium and -tungsten, [(CO)5—M=C=C=CR2] (M=Cr, R=C6H4CH3-p(1a), C6H4OCH3 (1b); M=W, R=C6H4CH3-p (1c), react with the alkynyl complexes [Cp(CO)2Fe—C≡CR′] (R′ = nBu (2), Ph (4)), [Cp*(CO)2Fe—C≡CnBu] (6), [Cp(CO){P(OMe)3}-Fe—C≡CnBu] (8) and [Cp(PPh3)Ni—C≡CnBu] (10) by cycloaddition of the C≡C bond of the alkynyl complexes to the Cα=Cβ bond of the allenylidene ligand to give 3a-c), (5), (7), and respectively. The cycloaddition is highly selective. The spectroscopic data of these 1,3-heterobinuclear complexes indicate a delocalized π-system (M=Cr, W; Y=[Fe(CO)2Cp], [Fe(CO)(P{OMe}3)Cp], [Fe(CO)2Cp*], [Ni(PPh3)-Cp]). X-ray structural analyses of the compounds 3a, 9a, and 11c reveal a “butterfly” conformation of the four-membered ring. Its puckering angle is 142° (3a), 152° (9a), and 151° (11c). All Complexes exhibit a moderate to strong negative solvatochromic behavior. The extent of the solvatochromic effect depends on [(CO)5M] and Y and considerably decreases when C=CR2 is replaced by e.g. CMe2.
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  • 36
    ISSN: 0009-2940
    Keywords: Phosphate - Phosphonate rearrangement ; Carbanions, benzylic, configurational stability of ; α-Hydroxyphosphonates, tertiary, chiral, non-racemic ; t-Butyl(phenyl)phosphinothioic acid, homochiral ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Optically active alcohols (ee ≥ 98%) such as 1-phenylpropanol, 1-(2-naphthyl)ethanol, 1-tetralol, and 1-indanol were transformed into diethyl phosphates 7a-d. sBuLi/TMEDA  -  induced phosphate - phosphonate rearrangement in diethyl ether furnished tertiary α-hydroxyphosphonates 8a-d of high enantiomeric purity (ee 94-98%) in yields of 43-83% with retention of configuration. The enantiomeric excesses were determined by using homochiral t-butyl(phenyl)phosphinothioic acid as chiral solvating agent.
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  • 37
    ISSN: 0009-2940
    Keywords: 1,1-Dithiolate ; Manganese complexes ; Rhenium complexes ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The cationic tetracarbonyl complex cis-[Mn(CO)4-(S2CPCy3)]+ undergoes addition of hydride ion to the central carbon of the S2CPR3 ligand to afford, after spontaneous dimerization with loss of CO, the dimer [Mn2(CO)6{μ-S2C(H)PCy3}2] (5a), which was characterized by analytical and spectroscopic methods as well as by X-ray diffraction. In the molecule of 5a each S2C(H)PCy3- ligand is coordinated to one manganese in an η2-S,S′ chelate fashion, and one sulfur of each ligand serves as a bridge to bind the other manganese atom, thus forming a distorted Mn2S2 square. This appears to be a very stable arrangement. Compound 5a can be more easily prepared by treating the perchlorato complex [Mn(CO)3(S2CPCy3)(OClO3)] (2a) with NaBH4. This procedure is general and can be used for the preparation of several derivatives containing either manganese or rhenium [M2(CO)6{μ-S2C(H)PR3}2] 5a-d. The reaction of cationic tricarbonyl complexes [M(CO)3(S2CPR3)(PPh3)]PF6 (M = Mn, Re) with NaBH4 produced the same dimers 5a or 5c by displacement of the PPh3 ligand. Treatment of the dimer 5a with excess PEt3 or P(OMe)3 leads to the cleavage of the bridges and loss of one CO and the PR3 group from the S2C(H)PR3 unit to afford ultimately the dithioformate complexes [Mn(CO)2(S2CH)(L)2] [L = PEt3, P(OMe)3].
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  • 38
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    Berichte der deutschen chemischen Gesellschaft 129 (1996), S. 1621-1625 
    ISSN: 0009-2940
    Keywords: Organo-zinc compounds ; Phosphaneiminato complexes ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Organo-Zinc Phosphaneiminato Complexes with Heterocubane StructureThe organo-zinc heterocubanes [ZnR(NPMe3)]4 with R = CH3 (1) and n-C4H9 (2) were prepared by the reaction of [ZnBr(NPMe3)]4 with MeLi and nBuLi, respectively, in hexane solution. In a similar reaction of nBuLi with [ZnI(NPMe3]4 the phosphaneiminato complex [Zn4I(nBu)4(NPMe3)3] (3) is formed. 1-3 were characterized by IR, NMR and MS spectroscopy, and by crystal-structure determinations. 1 and 2 possess heterocubane structures in which the zinc atoms are linked via μ3-N bridges of the phosphaneiminato groups, and all bond angles in the Zn4N4 core are close to 90°. A distorted heterocubane structure is observed for 3 with one of the NPMe3 moieties replaced by an iodine atom.
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  • 39
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    Berichte der deutschen chemischen Gesellschaft 129 (1996), S. 161-167 
    ISSN: 0009-2940
    Keywords: Sulfoxonium ylides ; 1,3-Dithietane 1,1,3,3-tetraoxide, silylated ; 1,3,5-Trithiane 1,1,3,3,5,5-hexaoxide, silylated ; Disulfenes, unsaturated ; Disulfenes, dianions of ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Sulfoxonium ylides 3a-h were synthesized by silylation of the cyclic methylene disulfones 1,3-dithietane 1,1,3,3-tetraoxide (1) and 1,3,5-trithiane 1,1,3,3,5,5-hexaoxide (4) with the silylating agents silyl nonafluorobutanesulfonates. The structure and constitution of the ylides were established with 1H-NMR, 13C-NMR, 29Si-NMR spectroscopy, mass spectrometry, and elemental analysis. On the route to the sulfoxonium ylides a new class of unsaturated disulfenes 7, 8, 12, 13 of 1 and 4 were synthesized via Knoevenagel and substitution reactions. Dianions of newly formed alkyl disulfenes 16a, b, e, f, and the trianion 17 were prepared and characterized by 1H-NMR and 13C-NMR spectroscopy and compared with the results of the ylides.
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  • 40
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    Berichte der deutschen chemischen Gesellschaft 129 (1996), S. 405-410 
    ISSN: 0009-2940
    Keywords: Osmium(0) complexes ; Nitrosyl complexes ; CS2, COS, SCNPh, and Ph2C=C=O as bidentate ligands ; Protonation and methylation reactions ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Addition of CS2 and Other Heteroallenes to the 16-Electron Osmium(0) Complexes trans-[OsCl(NO)(PiPr2R)2]The coordinatively unsaturated 16-electron compounds trans-[OsCl(NO)(PiPr2R)2] (1: R = iPr; 2: R = Ph) react with CS2 and COS to form the 1:1 adducts [OsCl(NO){κ2(C,S)-S=C=S}(PiPr2R)2)] (3, 4) and [OsCl(NO){κ2(C,S)-S=C=O}-(PiPr2R)2] (6, 7), respectively. While compounds 3, 4 are inert toward PMe3, the Os(COS) complexes 6, 7 react with tri-methylphosphane by abstraction of sulfur to give (OsCl(NO)-(CO)(PiPr2R)2] (8, 9). From 1 or 2 and phenylisothiocyanate the corresponding 1:1 adducts (OsCl(NO){κ2(C,S)-S=C=NPh}(PiPr2R)2] (10, 11) are obtained. Protonation and methylation reactions of 10 (R = iPr) with HBF4 or CF3SO3Me lead, by addition of the electrophile to the C=N nitrogen atom, to the formation of [OsCl(NO){κ2(C,S)-S=CNHPh}-(PiPr3)2]BF4 (12) and [OsCl(NO){κ2(C,S)-S=CN(Me)Ph}-(PiPr3)2]CF3SO3 (13). Treatment of 1 with diphenylketene yields [OsCl(NO){κ2(C,O)-O=C=CPh2}(PiPr3)2] (14). The X-ray structure analyses of 10 and 14 confirm the coordination of phenylisothiocyanate via S and C and of diphenylketene via O and C, respectively.
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  • 41
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    Berichte der deutschen chemischen Gesellschaft 129 (1996), S. 459-463 
    ISSN: 0009-2940
    Keywords: Cyclopentadienes ; Half-sandwich complexes ; Intramolecular nitrogen donors ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: 8-Lithioquinoline reacts with 2,3,4,5-tetramethylcyclopentenone to give 8-quinolylcyclopentadiene (1/2) after acidic workup and treatment with ammonia. Two of the possible three isomers are formed; the acidic protons on the Cp rings show unusual downfield shifts in the 1H-NMR spectra. Treatment with strong bases led to the intensely coloured anionic 4 which was converted into the trimethylsilyl derivative 5. This is a suitable starting compound for the trihalotitanium and -zirconium compounds 6 and 7. The two complexes were investigated by crystal structure analyses. In both cases the quinolyl nitrogen atom is coordinated to the metal.
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  • 42
    ISSN: 0009-2940
    Keywords: Silaethenes ; [4 + 2] Cycloadditions ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: On the Silaethene tBu2Si=C(SiMe3)2, and the Structure and Reactivity of Its [4 + 2] Cycloadduct with Ph2C=OFrom tBu2SiF—CLi(SiMe3)2 by LiF elimination only Me2Si= C(SiMe3)(SiMetBu2) (1b) instead of tBu2Si=C(SiMe3)2 (1a) is isolated. With benzophenone, silaethene 1b (from its THF adduct 1b · THF) forms at -78 °C a yellow [4 + 2] cycloadduct (5) and a colorless [2 + 2] cycloadduct (6). With increasing temperature 5 transforms into 6, and 6 transforms -more slowly - into the yellow [4 + 2] cycloadduct (7) of 1a and Ph2CO. It follows from this that the migration equilibrium 1a ⇄ 1b really exists. The structure of 7 shows a planar —O—CPh=C6H5-framework with the cycloadded atoms Si and C from -tBu2Si—C(SiMe3)2- located above the plane. The =C6H5—C bond (1.62 Å) is exceptionally long. 7 is a source for 1a which is trapped by acetone (formation of an ene product) and by benzaldehyde [formation of a [2 + 2] cycloadduct, unstable against cycloreversion into PhHC=C(SiMe3)2 and tBu2SiO-containing substances]. Reaction of 7 with trimethylsilyl azide, less reactive than acetone or benzaldehyde, leads - by way of 1a which transforms into 1b - to a trapping product of 1b (formation of a [3 + 2] cycloadduct, unstable against transformation into (RMe2Si)(Me3Si)CN2 with R = (Me3Si)2N, or cycloreversion into (tBu2MeSi)(Me3Si)CN2 and Me2SiNSiMe3-containing substances). Reaction of 1b or 1b · THF with acetone leads only to an ene reaction product of 1b. This means, that only undetectable amounts of 1a or 1a · THF are in equilibrium with 1b or 1b · THF. A minor substance which is shown by NMR at low temperatures besides 1b or 1b · THF is interpreted as a rotamer of 1b or 1b · THF.
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  • 43
    ISSN: 0009-2940
    Keywords: Phosphaalkynes ; Phosphaalkenes ; Spirocyclotrimerization ; Triphospha Dewar benzenes ; Phosphaalkyne cyclooligomers ; Cage compounds, phosphorus-carbon ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: In the presence of Lewis acidic derivatives of group 13 elements, phosphaalkynes 7 undergo spirocyclotrimerization with incorporation of the corresponding Lewis acids to form 10a-f. Scope and limitations of this novel cyclooligomerization process are examined. Starting from the spirocyclotrimer 10a reaction with the Lewis base dimethyl sulfoxide, we have in hand for the first time a method for the selective generation of two isomeric triphospha Dewar benzene derivatives (18, 19). Both can be trapped efficiently by further reaction with the phosphaalkyne to furnish the two novel phosphaalkyne cyclotetramers 20 and 21, both still possessing a phosphorus-carbon double bond. In the case of 21, further functionalization of the phosphaalkene unit is possible by [3 + 2] cycloaddition with a nitrile oxide (→ 23).
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    Berichte der deutschen chemischen Gesellschaft 129 (1996), S. 1029-1034 
    ISSN: 0009-2940
    Keywords: Hydrogen bonding ; Hydroxy carboxylic acids, self-assembly of ; Crystal engineering ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The substituted 6-hydroxy-trans-3-hexenoic acids 2a and 2b are prepared by an organometallic template reaction involving a sequence of CC coupling reactions between a CO2 equivalent, butadiene, and 3-cyclopenten-1-one or 3,4-diphenyl-3-cyclopenten-1-one, respectively. In the crystal 2a assembles to form an infinite ribbon-type structure, exhibiting an alternating array of 12 and 18 atom-containing loops. The former are each constructed by an alternating CO2H/OH/CO2H/OH sequence, originating from four different monomeric units, that are linked together by means of hydrogen bonds. Two complementary ribbons of 2a are connected by van der Waals interactions to form staples that constitute the microscopic building blocks of the true (2a)n structure in the crystal. Stacks of cyclopentene π bonds are oriented inside the columnar structure of 2a. Acid 2b also forms a related ribbon-like assembly in the solid state. Here the bulky 3,4-diphenylcyclopentadienylidene moieties are oriented laterally at the ribbons, and van-der-Waals interactions with adjacent ribbons construct a three-dimensional hydroxyhexenoic acid network.
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  • 45
    ISSN: 0009-2940
    Keywords: Dithioxophosphoranes ; Diselenoxophosphoranes ; Internal coordination ; Steric protection ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Some dithioxophosphoranes 3 stabilized by intramolecular coordination with a dialkylamino group were prepared, and their structures were analyzed by X-ray crystallography involving [2,4-di-tert-butyl-6-(isopropylmethylamino)phenyl]- (3c), {2,4-di-tert-butyl-6-[(dimethylamino)methyl]phenyl}- (3f), and {2,4-di-tert-butyl-6-[2-(dimethylamino)-1,1-dimethylethyl]phenyl}dithioxophosphorane (3h). The bond between the phosphorus atom and the aromatic ring is flexible and the angle narrows with decreasing ring size of the intramolecular coordination. The 31P-NMR signals are shifted to higher field with increasing ring size of the intramolecular coordination or strength of coordination. Similarly, the corresponding diselenoxophosphoranes 4 were prepared. Both their 31P- and 77Se-NMR signals are shifted to higher field with increasing contribution of intramolecular coordination.
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  • 46
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    Berichte der deutschen chemischen Gesellschaft 129 (1996), S. 1093-1098 
    ISSN: 0009-2940
    Keywords: Indium tris(thiobenzoate) ; Triethylammonium tetrakis(thiobenzoato)indate ; Tin, butyl-, tris(thiobenzoate) ; Tin, dichloro-, bis(thiobenzoate) ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Indium(III) and tin(IV) thiocarboxylates were prepared and characterized on the basis of their IR, 13C- and 19Sn-NMR data. Indium tris(thiobenzoate) (1) decomposes into a sulfido complex In (S)[S(O)CPh] (2a). The corresponding tris(thioacetate) In[S(O)CMe]3 is thermally too unstable to be isolated. The anionic tetrakis complex [Et3NH]{In[S(O)CPh]4} (3) was characterized by X-ray crystallography which revealed a distorted tetrahedral coordination at the In atom. X-ray diffraction analysis of the complexes BuSn[S(O)CPh]3 (4) and Cl2Sn[S(O)CPh]2 (7) showed distorted tetrahedral and cis-octahedral structures, respectively.
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  • 47
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    Berichte der deutschen chemischen Gesellschaft 129 (1996), S. 1107-1113 
    ISSN: 0009-2940
    Keywords: Tripod ligands ; Hydrazines, substituted ; Diazenes ; Cobalt(III), fivefold coordination of ; Cobalt(II), fivefold coordination of ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The coordination behaviour of ligands having the same basic constitution RN=NC(=X)R′ (X = O, NR″, S) in their tripod cobalt derivatives has been analyzed. The ligands themselves may be considered as neutral heterodiene compounds and are in this respect vinylogues to diazenes RN=NRy′. Two- electron reduction of these neutral species results in dianionic heterosubstituted heteroolefins RN- -N=C(X-)R′. Due to their redox ambiguity the oxidation state of the metal M in chelate complexes is not a priori evident. Compounds tripod [5: X, R′ = O, Ph; 6; (X, R′) = (py); 7: X, R′ = S, NH2] are best described as containing low-spin Co(III) and dianionic ligands. Co(II) species are obtained with diethyl azodicarboxylate EtOOCN=NCOOEt as the ligand. In the mononuclear compound, with only one nitrogen and one carbonyl oxygen of the ligand acting as donor groups, the neutral ligand is coordinated to give the high-spin cobalt(II) species tripod (8). In the dinuclear compound 9 with both of the nitrogen atoms and carbonyl groups involved in coordination the dianionic ligand bridges two high-spin cobalt(II) centers to give tripod (9) as a derivative with two fused five-membered chelate rings. In addition to the conventional analytical techniques X-ray structure analyses, cyclovoltametric measurements, magnetic susceptibility and ESR data are used to characterize the compounds.
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  • 48
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    Berichte der deutschen chemischen Gesellschaft 129 (1996), S. 1131-1142 
    ISSN: 0009-2940
    Keywords: Stannyl complexes ; Plumbyl complexes ; Tungsten complexes ; Molybdenum complexes ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Transition-Metal Stannyl Complexes, 10 - Molybdocen and Wolframocen Derivatives with Two Different Main-Group-4 LigandsReactions of Li[Cp2MSnPh3] (M = Mo, W) with CH3I, BuBr, PhCH2Br, PhC(O)Cl or Br(CH2)nBr (n = 4,5) yield Cp2M(R)SnPh3 [R = CH3, Bu, CH2Ph, C(O)Ph, (CH2)nBr], while tBuBr or CH3C(O)Cl give the hydrido complexes Cp2M(H)SnPh3. A silyl stannyl complex is only obtained from Li[Cp2WSnPh3] and Me3SiOSO2CF3, but not with Me3SiCl or from the anionic Mo complex. In contrast, the reactions of chlorostannanes provide the bis(stannyl) complexes Cp2M(SnR′3)SnPh3 or Cp2M(SnR′2Cl)SnPh3. R/Cl exchange at the tin atom is observed when an excess of the chlorostannane is used. Upon reaction of Li[Cp2MSnPh3] with Ph3PbCl only Cp2M(PbPh3)SnPh3 is formed, while a mixture of Cp2M(PbMe3)SnPh3 and Cp2M(PbMe2Cl)SnPh3 is obtained with Me3PbCl due to redistribution reactions. The structures of Cp2W(SnPh3)C(O)Ph, Cp2W(SnPh3)SntBu2Cl and Cp2W(SnPh3)PbMe2Cl were determined by X-ray structure analyses.
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  • 49
    ISSN: 0009-2940
    Keywords: Thioaldehyde complexes ; Selenoaldehyde complexes ; Thietane complexes ; Selenetane complexes ; Rearrangements ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Pentacarbonyl(thiobenzaldehyde)tungsten und pentacarbonyl(selenobenzaldehyde)tungsten (1a and 1b) undergo a thermal [2 + 2] cycloaddition with several vinyl ethers to give highly substituted transition metal-coordinated thietanes and selenetanes. The addition is highly regio- and stereospecific. The products undergo acid-catalyzed rearrangements, which lead to thermodynamically more stable diastereomers of the thietanes and selenetanes. The stereochemistry of both addition and rearrangement was established by reaction of deuterium-labeled vinyl ethers and by reaction of the cis and trans isomers of ethyl propenyl ether. The crystal structure of the bicyclic addition product of 1a and 3,4-dihydro-2H-pyran is reported.
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  • 50
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    Berichte der deutschen chemischen Gesellschaft 129 (1996), S. 1251-1257 
    ISSN: 0009-2940
    Keywords: Zinc complexes ; Cysteine ligands ; Histidine ligands ; Imidazole ligands ; Pyrazolylborate ligands ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Highly substituted pyrazolylborate ligands TpR,Me were used to limit the coordination number of zinc towards cysteine- and histidine-derived coligands. Monodentate thiolate attachment (→ 1a-f) was achieved with N- and C-protected cysteine, monodentate carboxylate attachment (→ 3) with N-protected histidine. C-protected cysteine was found to form a five-membered N,S-chelate ring (2). While imidazole coordination with N- and C-protected histidine could not be achieved, cationic pyrazolylborate-zinc-coligand complexes [TpZn-L]+ (4a, b) were obtained for L = 2-methylimidazole. The new complexes were characterized by their spectra and three structure determinations.
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  • 51
    ISSN: 0009-2940
    Keywords: Organotungsten selenolates ; 77Se NMR ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Organotungsten-selenolato complexes were prepared in moderate yields by insertion of selenium into the alkali metaltungsten bonds of MSeW(CO)3cp (M = Li, Na) and subsequent reactions with the organohalides o-, m-, and p- C6H4(CH2Br)2, C6H5CHBr2, m-C6H4(CHBr2)2 and C6H5CCl3. The 77Se-NMR data of the new complexes are discussed and compared with those of related complexes derived from organomonohalides. Moreover, the X-ray crystal structures of C6H5CH2W(CO)3cp (1), μ-[m-C6H4{CH2SeW(CO)3cp}2] (3), μ-[p-C6H4{CH2SeW(CO)3cp}2] (4), and C6H5CH[SeW-(CO)3cp]2 (5) were determined. In complex (1), the W-CH2 bond length is 2.374 Å; the W-Se bond lengths in the complexes 3, 4 and 5 are all in the range 2.625-2.655 Å, corresponding to W-Se single bonds.
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  • 52
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    Berichte der deutschen chemischen Gesellschaft 129 (1996) 
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
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  • 53
    ISSN: 0009-2940
    Keywords: Suzuki coupling ; π Complexes, organometallic ; π Complexes, dihaloarene ; Ruthenium complexes ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The synthesis of a terphenyl derivative complexed by the cationic moiety Cp*Ru+ by Suzuki coupling of [Cp*Ru(BrC6H4Br)]OTf with phenyl boronic acid under catalysis of Pd(PPh3)4 in a DME-water mixture at 85°C in quantitative yield is reported. The stable coupling product 3 was characterized by X-ray crystal structure analysis.
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  • 54
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    Berichte der deutschen chemischen Gesellschaft 129 (1996), S. 1313-1322 
    ISSN: 0009-2940
    Keywords: Vinylidene complexes ; Allenylidene complexes ; Ene type reactions ; Atom economial reactions ; Reconstitutive additions ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Ruthenium complexes catalyze a variety of addition or isomerization reactions that are highly atom economical. Terminal alkynes react with allyl alcohols to form β,γ-unsaturated ketones that can be readily isomerized to α,β-unsaturated ketones via transient vinylidene complexes. A cyclization via a transient allenylidene complex concomitant with this addition represents a novel way to build heterocycles. Ancillary studies with these catalysts revealed an internal oxidation reduction whereby allyl alcohols are isomerized to saturated ketones and propargyl alcohols are isomerized to α,β-unsaturated carbonyl compounds. Consideration of the reaction mechanism led to a general Alder ene type reaction wherein alkynes serve as the enophile and alkenes serve as the ene component. These discoveries have led to a number of efficient total syntheses of biologically interesting targets. Mechanistic investigations into the activation of a ruthenium complex led to the discovery of a novel bis-homo-Diels-Alder reaction of 1,4-cyclooctadiene.
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  • 55
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    Berichte der deutschen chemischen Gesellschaft 129 (1996), S. 1373-1377 
    ISSN: 0009-2940
    Keywords: Thionitrosyl azide ; Thiazyl azide ; Nitrosyl azide ; Tetranitrogen sulfide ; Calculations, ab initio ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Stimulated by the recent detection of nitrosyl azide (N3—N=O), we investigated the stability of the sulfur analogues thionitriosyl azide (N3—N=S) and thiazyl azide (N3—S≡N) by using ab initio MO calculations up to the QCISD(T)/6-311+G(d)//QCISD/6-311G(d) + ZPE level. Both azides have a similar energy content. While thionitrosyl azide is not stable with respect to N2 elimination, thiazyl azide resists to this process by an energy barrier of about 110 kJ/mol. The NS and N3 fragments resulting from homolytic cleavage lie about 100 kJ/mol above the azides. The five-membered ring is thermodynamically much more stable than both azides but kinetically unstable with respect to cheletropic decomposition yielding N2S + N2. Overall, trans-thiazyl azide is the most likely candidate for experimental observation of, for example, the reaction of NS+ salts with the azide anion. IR wavenumbers of the azides were also predicted.
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  • 56
    ISSN: 0009-2940
    Keywords: Amido complexes ; Titanium(III) compounds ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Syntheses, Properties, and Crystal Structures of the Titanium(III) Amido Complexes Ti[N(SiMe3)2]3, [TiCl2{N(SiMe3)2}(THF)2], and [Na(12-Crown-4)2][TiCl2{N(SiMe3)2}2]TiCl3(THF)3 reacts with NaN(SiMe3)2 to furnish [TiCl2{N(SiMe3)2}(THF)2] (1), whereas in the presence of 12-crown-4 the ionic amido complex [Na(12-crown-4)2][TiCl2{N(SiMe3)2}2] (5) is obtained besides [Na(12-crown-4)2][TiCl4(THF)] (4). On the other hand, the titanium(III) amido complex Ti[N(SiMe3)2]3 (2), the crystal structure of which was solved, reacts with NaN(SiMe3)2 in the presence of 12-crown-4 with deprotonation of one of the methyl groups to give the carbometalated complex [Na(12-crown-4)2][Ti{N(SiMe3)2}2{N(SiMe 3CH2)}] (3).
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  • 57
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    Berichte der deutschen chemischen Gesellschaft 114 (1981), S. 3079-3101 
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Building units for Oligosaccharides, XXIX. Synthesis of a Trisaccharide Chain of N-Acetylglucosamine, Galactose and Rhamnose of an O-Determinant from Escherichia coli. Dependence of Stereoselectivity of the α-Glycoside Synthesis on the Reactivity of the PyranosylhalideThe mercury salt catalysed reaction of substituted α-D-galactosyl halides with the reactive 4-OH groups of the rhamnosides 18 and 19 were studied. The order of reactivity of the halides increases with the following substituents: O-acetyl 〈 O-glucosyl 〈 O-benzyl. The order of selectivity, towards the α-glycoside, was the reverse. The selectivity can be improved by either decreasing the reactivity of the glycosyl halide, in the case of highly reactive hydroxyl groups, or by decreasing the nucleophilicity of the hydroxyl groups, in the case of highly reactive halides. Various trisaccharides, like 58 which represents the repeating-unit of the lipopolysaccharide from Escherichia coli O 75, were synthesized from N-acetylglucosamine, galactose and rhamnose.
    Notes: Die Quecksilbersalz-katalysierte α-Glycosidsynthese von gemischt substituierten α-D-Galactosylhalogeniden mit den reaktiven 4-OH-Gruppen der Rhamnoside 18 und 19 wird untersucht. Die Reaktivität der Halogenide nimmt bei Anwesenheit der folgenden Substituenten zu: O-Acetyl 〈 O-Glycosyl 〈 O-Benzyl. Parallel dazu nehmen die Selektivität und der Anteil and α-Glycosid ab. Notwendige Selektivitätsverbesserungen können bei zu reaktiven OH-Gruppen durch Verminderung der Reaktivität des Glycosylhalogenids, bei zu reaktiven Glycosylhalogeniden durch Verminderung der Reaktivität der OH-Gruppe erzielt werden. Verschiedene Trisaccharideinheiten aus N-Acetylglucosamin, Galactose und Rhamnose werden synthetisiert, wobei 58 einer Teil-struktur der repeating-unit der O-Determinante des Lipopolysaccharids aus Escherichia coli O 75 entspricht.
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  • 58
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    Berichte der deutschen chemischen Gesellschaft 114 (1981), S. 3115-3125 
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Building Units for Oligosaccharides, XXXI. Synthesis of the Repeating-Unit of the O-Specific Chain of the Lipopolysaccharide from Escherichia coli O 75Reaction of the trisaccharidehalide-block 12 with the benzyl rhamnoside 13 gave a tetrasaccharide which, after complete removal of the protecting groups, yielded the branched tetrasaccharid 1 (see german summary). This represents the repeating-unit of the O-specific chain of the lipopolysaccharide from Escherichia coli O 75. A simular reaction between the block 12 and the 8-ethoxycarbonyloctyl rhamnoside 19 leads to the tetrasaccharide 20 which contains a suitable spacer-unit for coupling with a protein to give a synthetic antigen.
    Notes: Durch eine Synthese, bei der der Trisaccharidhalogenid-Block 12 verwendet wird, läßt sich nach vollständiger Entblockierung das verzweigte Tetrasaccharid erhalten, das die repeating-unit der O-spezifischen Kette des Bakteriums Escherichia coli O 75 darstellt. Durch Verknüpfung des Blocks 12 mit dem Rhamnosid 19, einem Glycosid des 8-Ethoxycarbonyloctanols, wurde das spacer-haltige Tetrasaccharid 20 synthetisiert. Dieses ist ein Hapten, das zur Anknüpfung an ein Protein und somit zur Gewinnung eines synthetischen Antigens geeignet ist.
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  • 59
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    Berichte der deutschen chemischen Gesellschaft 114 (1981), S. 3549-3557 
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Substituted Mononucleus Carbonyliron HydridesSubstitution of H2Fe(CO)4 by ligands like L = As(C6H5)3, Sb(C6H5)3 and P(OC6H5)3 in 1:1 ratio leads to fac monosubstituted compounds H2Fe(CO)3L. A 1:2 ratio results in the isolation of disubstituted complexes H2Fe(CO)2L2, L = P(OCH2)3CC2H5, P(OC6H5)3. The structure of H2Fe(CO)3As(C6H5)3 Was elucidated by X-ray analysis.
    Notes: Substitution von H2Fe(CO)4 mit Liganden L = As(C6H5)3, Sb(C6H5)3 und P(OC6H5)3 im Molverhältnis 1:1 Führt zu fac-Monosubstitutionsverbindungen H2Fe(CO)3L. Im Verhältnis 1:2 können trans-Disubstitutionskomplexe H2Fe(CO)2L2, L = P(OCH2)3CC2H5, P(OC6H5)3, erhalten werden. Von H2Fe(CO)3As(C6H5)3 wurde eine Röntgenstrukturanalyse ausgeführt.
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  • 60
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    Berichte der deutschen chemischen Gesellschaft 114 (1981), S. 3518-3532 
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Reactivity of the Silaethene Me2Si=C(SiMe3)2: Thermolysis of (Me3Si)2(Me2XSi)CLi (X e. g. (PhO)2PO2) in the Presence of Silaethene Trapping ReagentsSilaethene Me2Si=C(SiMe32 (1), generated as a reaction intermediate by the thermal elimination of LiX from Me2XSi—CLi(SiMe3)2, combines with the reactants a-b (e. g. Me3Si—Cl, Me3Si—OMe) with insertion in the a-b bond, with a = b-c-H (e. g. CH2=CMe—CH2—H) under ene-reaction and with (e. g. CH2=CR—CR=CH2, O=N=N, Ph2C=NSiMe3, Me3SiN=NSiMe3, PhC=N) under [2 +4]-, [2 + 3]- [2 + 2]- as well as [2 + 2 + 2]-Cycloaddition. Some of the cycloadducts, so obtained, are thermolabile and decompose under cycloreversion, which may lead to the formation of 1 and also to Me2Si=NSiMe3. The following order of relative reactivity of 1-trapping reagents has been found (formation of 1 at -10°C): Me3Si—NMe2 Me3Si—Cl 〈 PhC≡N 〈 1,3-butadien 〈 2.3-Dimethyl-1,3-butadien ≍ isobuten 〈 Me3Si—OMe 〈 Ph2C=NSiMe3 〈 PhN=NPh 〈 Me3SiN=NSin=NSiMe3 ≪ Ph2C=O, Me3SiN=N=N.
    Notes: Das durch thermische LiX-Eliminierung aus Me2XSi—CLi(SiMe3)2 als Reaktionszwischenstufe erzeugbare Silaethen Me2Si=C(SiMe3)2 (1) reagiert mit Reaktanden a-b (z. B. Me3Si—Cl, Me3Si-OMe) unter Insertion in die a-b-Bindung, mit a = b-c-H (z. B. CH2 CMe—CH2—H) unter En-Reaktion und mit (z. B. CH2=CR—CR=CH2, O=N=N, Ph2C=NSiMe3, Me3SiN=NSiMe3, PhC≡N) unter [2 +4]-, [2+3]-[2 + 2]- sowie [2 + 2 + 2]-Cycloaddition ab. Die erhaltenen Cycloaddukte sind zum Teil thermolabil und zerfallen unter Cycloreversion u. a. unter Bildung von 1 sowie auch Me2Si=NSiMe3. Folgende Reihe relativer Reaktivitäten von 1-Fängern wurde gefunden (Erzeugung von 1 bei -10°C): Me3Si—NMe2 Me3Si—Cl 〈 PhC≡N 〈 1,3-Butadien 〈 2,3-Dimethyl-1,3-butadien ≍ Isobuten 〈 Me3Si—OMe 〈 Ph2C=NSiMe3 〈 PhN=NPh 〈 Me3SiN=NSiMe3 ≪ Ph2C=O, Me3Sin=N=N.
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  • 61
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    Berichte der deutschen chemischen Gesellschaft 114 (1981), S. 3533-3548 
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Aliphatic Azo Compounds, XIII: cis- and trans-1-AzonorbornaneThe rates of isomerisation of cis-1-azonorbornane to the trans-isomer at 96.6°C in a series of aprotic solvents follow a linear correalation with ET30. The small slope of the correlation -0.034 argues for isomerisation via semilinearisation in agreement with theory. In protic solvents the isomerisation proceeds faster possibly due to a faster isomerisation by bond rotation which could be favoured by H-bonding. The heat and the activation parameters of the isomerisation and the activation parameters of thermal decomposition of trans-1-azonorbornane allow the construction of a complete enthalpy diagram of this system. The structure of cis-1-azonorbornane was determined by X-ray analysis at -60°C. The observed angle deformations and the normal NN-bond lengths are reproduced by force field calculations.
    Notes: Die Isomerisierungsgeschwindigkeit von cis- in trans-1-Azonorbornan (1) folgt bei 96.6°C linear dem Polaritätsparameter ET30 in verschiedenen aprotischen Lösungsmitteln. Die geringe Steigung -0.034 dieser Korrelation deutet auf einen theoretisch vorgeschlagenen einfachen Inversionsmechanismus. In protischen Lösungsmitteln verläuft die Isomerisierung viel schneller, wofür ein durch H-Drücken begünstigter Rotationsmechanismus Möglich gehalten wird. Reaktionsenthalpie und Aktivierungsparameter der cis-trans-Isomerisierung und die Aktivierungsparameter der Thermolyse von trans-1-Azonorbornan gestatten die Aufstellung eines vollständigen Enthalpiediagramms. Die Struktur von cis-1 wurde durch Röntgenanalyse bei -60°C bestimmt. Die starke Winkeldeformation und der normale NN-Abstand im Kristall werden durch Kraftfeldrechnungen richtig wiedergegeben.
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  • 62
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Metalcarbonyl Syntheses, X: Synthesis of New Niobium and Tantalum Halfsandwich Complexes. Molecular Structure of the Parent Compound (η5-C5H5)Nb(CO)4The halfsandwich complexes (η5-C5H4CH3)Nb(CO)4 (3a), [η5-C5(CH3)5]Nb(CO)4 (3b), (η5-C5H4CH3)Ta(CO)4 (3c), and [η5-C5(CH3)5]Ta(CO)4 (3d) are accessible by reductive high-pressure carbonylation of the corresponding NbV- and TaV precursors (η5-C5R4R′)MCl4 (2a-d). Successive introduction of methyl groups in the cyclopentadienyl ring facilitates the reduction of the halogeno complexes 2a-d; moreover, the niobium complexes are more susceptible to reduction than their tantalum counterparts. Upon photolysis of the carbonyl complexes 3a-d in tetrahydrofuran, the solvens complexes of type (η5-C5R4R′)M(CO)3(THF) (4a-d) are generated. The parent compound (η5-C5H5)Nb(CO)4 (1) has a regular square-pyramidal structure as shown by X-ray analysis.
    Notes: Die Halbsandwich-Komplexe (η-5C5H4CH3)Nb(CO)4 (3a), [η5-C5(CH3)5]Nb(CO)4 (3b), (η5-C5H4CH3)Ta(CO)4 (3c) und [η5-C5(CH3)5]Ta(CO)4 (3d) sind durch reduzierende Hochdruckcarbonylierung der entsprechenden NbV-bzw. TaV-vorstufen (η5-C5R4R′)MCl4 (2a-d) synthetisierbar. Die Reduzierbarkeit der Halogeno-Komplexe, 2a-d, wird durch sukzessive Einführung von Methyl-Substituenten in den Cyclopentadienyl-Ring erleichtert und ist bei den Niob-Verbindungen mit milderen Reduktionsmitteln als bei den analogen Tantal-Komplexen möglich. Bei der Photolyse von 3a-d in Tetrahydrofuran entstehen die Solvens-Komplexe (η5-C5R4R′)M(CO)3(THF) (4a-d). Die Stammsubstanz (η5-C5H5)Nb(CO)4 (1) wurde röntgenstrukturanalytisch untersucht und besitzt eine unverzerrt tetragonal-pyramidale Molekülstruktur.
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  • 63
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    Berichte der deutschen chemischen Gesellschaft 114 (1981), S. 3572-3580 
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Complexes of Germanium Dichloride with 1,2-Bis(diphenylphosphino)ethane: A Semi-Chelate and A Double-Ylide1,2-Bis(diphenylphosphino)ethane (dppe) reacts with the germanium dichloride dioxane complex depending on the stoichiometric ratio to give a 1:2 dppe-bridged bis(germylene) complex (1) or a 1:1 complex (2) that shows equilibration of both phosphorus atoms in 31P-NMR. The crystal structure of 2 has been determined from single crystal X-ray data. The compound crystallizes with 8 units dppe-GeCl2· 1/2 C6H6 in a unit cell of symmetry A 2/a-C2h6 in a monoclinic system. The dppe-GeCl2 molecules contain a novel semi-chelating type of coordination of the dppe ligand [distorted Ψ-trigonal bipyramidal coordination at Ge11 with an exceptionally long distance Ge-P(apical)]. 2 thus represents an intermediate structure between chelate complex and phosphorus ylid.
    Notes: 1,2-Bis(diphenylphosphino)ethan (dppe) reagiert mit dem Germanium(II)-chlorid-Dioxankomplex je nach Mengenverhältnis zu einem dppe-verbrückten Bis(germylen)-Komplex (1) oder zu einem 1:1-Komplex (2), der sich durch die Äquivalenz der Phosphanfunktionen in Lösung (31PNMR) auszeichnet. 2 kristallisiert mit 1/2 C6H6 monoklin mit acht Einheiten der Formal dppe-GeCl2· 1/2 C6H6 in der Elementarzelle, Raumgruppe A 2/a-C2h6. Die verzerrt Ψ-trigonal-bipyramidale Koordination um Ge11 mit ungewöhnlich langem Abstand Ge-p(apikal) weist 2 als Komplex mit halb-chelierendem dppe-Liganden aus (Zwischenstellung zwischen Chelatkomplex und einfachem \documentclass{article}\pagestyle{empty}\begin{document}$ \mathop {\rm P}\limits^{\rm + } - \mathop {{\rm Ge}}\limits^{\rm - } - {\rm Ylid} $\end{document}).
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  • 64
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    Berichte der deutschen chemischen Gesellschaft 114 (1981), S. 3581-3588 
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Autoxidation of Trialkylboranes, II: 1H NMR Spectroscopic Investigations on the Mechanism of the Redox Reaction between Trialkylboranes und Dialkyl(alkylperoxy)boranesThe intermolecular redox reaction between dimethyl(methylperoxy)borane and [D9]trimethylborane, triethylborane, tri-n-propylborane, triisopropylborane, and tri-n-butylborane, as well as between [D9]dimethyl(methylperoxy)borane and trimethylborane was investigated directly in an NMR spectrometer. From the CIDNP effects a mechanism of this redox reaction was deduced, which can be considered as generally valid for any reaction between (alkylperoxy)boranes and alkylboranes. According to this mechanism, the alkoxy group of the peroxide is transferred to the boron atom of the alkylborane after homolysis of the O—O bond. The four-coordinate boron compound eliminates instantly an alkyl radical, which forms a radical pair in the singlet state with the boroxyle radical left after the homolysis of the peroxide.
    Notes: Die intermolekularen Redoxreaktionen Zwischen Dimethyl(methylperoxy)boran und [D9]Trimethylboran, Triethylboran, Tri-n-propylboran, Triisopropylboran und Tri-n-butylboran sowie zwischen [D9]Dimethyl(methylperoxy)boran und Trimethylboran wurden in Lösung im 1H-NMR-Spektrometer untersucht. Aus den CIDNP-Effekten wird ein allgemeingültiger Mechanismus der Redoxreaktion zwischen (Alkylperoxy)boranen und Alkylboranen abgeleitet. Danach wird in einem Stoßkomplex zwischen (Alkylperoxy)boranen und Alkylboran durch Homolyse der O—O-Bindung gezielt die Alkoxygruppe des Peroxids auf das Boratom des Alkylborans übertragen. Das vierfach koordinierte Alkoxyalkylboran stößt sofort ein Alkyl-Radikal ab, welches mit dem Boroxylradikal aus der Spaltung des Peroxids zu einem Radikalpaar mit Singulett-Konfiguration der Radikalelektronen zusammenfindet.
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    Berichte der deutschen chemischen Gesellschaft 114 (1981), S. 3589-3598 
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Highly Fluorinated Phosphorus Ylides and Phosphonium SaltsThe (perfluoroalkyl)iodophosphanes n-C6F13PI2 and (n-C6F13)2PI, obtained from n-C6F13I and white phosphorus at 235°C under pressure, are converted into the chlorides n-C6F13PCI2 and (n-C6F13)2PCl with HgCl2. The chlorides are methylated with LiCH3 to form the methylphosphanes n-C6F13P(CH3)2, (6) and CH3P(n-C6F13)2 (5), respectively. Only 6, but not 5, can be quaternized with CH3I to yield a phosphonium salt, [n-C6F13P(CH3)3]I (8). In reactions of 8 with strong bases no corresponding ylide is generated, but a phosphorane n-C6F13P(CH3)4 is obtained instead. More highly fluorinated phosphonium salts could not be prepared. - The Phosphanes (CH3)2PC6F5 (11) and CH3P(C6F5)2 (12) yield onium salts [(CH3)3PC6F5]X (13) and [(CH3)2P(C6F5)2]X (14), resp., when treated with methylating agents. P(C6F5)3 undergoes dearylation reactions under comparable conditions. 13 and 14 are transformed into dark red unstable ylides, which oligomerize with autocondensation and could not be identified. From 12 and C6F5CH2Br a red ylide 17 is obtained, via the onium salt 16, which can be isolated and characterized by spectroscopic data. Stable yellow ylides R3P=CHC6F5 (19a-c, R = CH3, i-C3H7, C6H5) are generated similarly from the phosphonium salts [R3PCH2C6F5]Br. Reduction of the carbanion nucleophilicity by the C6F5 groups appears to prevent autocondensation in these cases.
    Notes: Die aus weißem Phosphor und n-C6F13I bei 235°C unter Druck dargestellten (Perfluoralkyl)iodphosphane n-C6F13PI2 und (n-C6F13)2PI werden mit HgCl2 in die Chloride n-C6F13PCl2 and (n-C6F13)2PCl umgewandelt und diese mit LiCH3 in die Methylphosphane n-C6F13P(CH3)2 (6) und CH3P(n-C6F13)2 (5) übergeführt. Von diesen ist nur 6 mit CH3I quartärisierbar. Das entstehende Salz [n-C6F13P(CH)3)3]I (8) ergibt mit starken Basen nicht das korrespondierende Ylid, sondern das Phosphoran n-C6F13P(CH3)4 (10). Höher fluorierte Phosphoniumsalze sind nicht zugänglich. - Die Phosphane (CH3)2PC6F5 (11) und CH3P(C6F5)2 (12) ergeben mit Methylierungsmitteln noch die Oniumsalze [(CH3)3PC6F5]X (13)bzw. [(CH3)2P(C6F5)2]X (14). P(C6F5)3 erleidet dagegen unter vergleichbaren Bedingungen eine Entarylierung. 13 und 14 werden von starken Basen in tief rote instabile Ylide übergeführt, die durch Autokondensation oligomerisieren und nicht faßbar sind. Mit C6F5CH2Br entsteht aber aus 12 über das Oniumsalz 16 ein rotes Ylid 17, das isoliert und spektroskopisch charakterisiert werden kann. Analog ergeben sich aus Salzen [R3PCH2C6F5]Br stabile gelbe Ylide R3P=CHC6F5 (19a-c, R = CH3, i-C3H7 und C6H5). Die Verminderung der Carbanion-Nucleophilie dieser Ylide durch die C6F5-Gruppe verhindert die Autokondensation.
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    Berichte der deutschen chemischen Gesellschaft 114 (1981), S. 3609-3624 
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Oxidative Additions to 2-Amino-4,4,5,5-tetrakis(trifluoromethyl)-1,3,2-dioxaphospholaneOxidative addition of HF, Cl2 and (CF3)2CO to the title compound 6 furnishes the phosphoranes 2, 9, and 3, respectively. In the case of NH4[OC(CF3)C(CF3)2OH] (4) the hydrospirophosphorane 1 is obtained via a substitution reaction followed by an oxidative addition. Compound 9 is a precursor for the aminotetraalkoxyphosphoranes 5, 8, and the very stable phosphazene 10 which is formed by loss of HCl by thermolysis. Due to a slow ligand exchange the 19F NMR spectrum of phosphorane 3 exhibits eight magnetically non equivalent CF3 groups. By means of 19F homodecoupling experiments extensive through space coupling is found in the molecule. The x-ray structure analysis of 3 shows a slight distortion from the trigonal bipyramidal geometry at phosphorus. For comparison, F2PNH2 and tBu2PNH2 react with (CF3)2 to form (CF3)2C=NH, the aminofluorophosphorane 11, F2P(=O)OCH(CF3)2 (13) bzw. von tBu2P(=o) (12) and tBu2P(=O)OCH(CF3)2 (14), respectively.
    Notes: Durch oxidative Addition von HF, Cl2 und (CF3)2CO and die Titelverbindung 6 entstehen die Phosphorane 2, 9 und 3; mit NH4[OC(CF3)2C(CF3)2OH] (4) wird unter Abspaltung von NH3 und oxidativer Addition das Hydrophosphoran 1 erhalten. Durch Substitution von Chlor lassen sich aus 9 die Aminoalkoxyphosphorane 5 und 8 synthetisieren, während die Thermolyse unter HCl-Abspaltung zu dem äußerst beständigen Phosphazen 10 führt. Verbindung 3 zeigt im 19F-NMR-Spektrum wegen eingeschränkter dynamischer Prozesse acht magnetisch nicht äquivalente CF3-Gruppen. Durch 19F-Homoentkopplungsexperimente werden weitreichende Raumkopplungen nachgewiesen. Die Röntgenstrukturanalyse von 3 ergibt eine annähernd trigonal-bipyramidale Koordination des Phosphors, F2PNH2 und tBu2PNH2, zur vergleichenden Betrachtung herangezogen, reagieren mit Hexafluoraceton unter Bildung von (CF3)2C=NH sowie des Amino-fluorphosphorans 11 und des Phosphorsäureesters F2P(=O)OCH(CF3)2 (13) bzw. von tBu2P(=O)H (12) und tBu2P(=O)OCH(CF3)2 (14).
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    Berichte der deutschen chemischen Gesellschaft 114 (1981), S. 3634-3642 
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Au55[P(C6H5)3]12Cl6- a Gold Cluster of an Exceptional sizeThe reduction of (C6H5)3PAuCl with B2H6 in benzene yields Au9,2[P(C6H5)3]2Cl which is characterized by means of molecular weight determinations as Au55[P(C6H5)3]12Cl6. A simple model, based on an arrangement of close-packed gold atoms, leads to a gold cluster the structure of which is in good agreement with the unusual chemical composition. The Mößbauer spectrum of the compound shows four different kinds of gold atoms: a metallic part (Au13-nucleus), Au atoms coordinated by P(C6H5)3 and Cl ligands, resp., as well as uncoordinated surface gold. The complex can be decomposed by bromine and iodine to (C6H5)3PAuCl, (C6H5)3PAuBr(I), and metallic gold. The thermolysis at 50°C leads to [(C6H5)3P]2AuCl and gold quantitatively.
    Notes: Die Reduktion von C6H5)3PAuCl mit B2H6 in Benzol ergibt Au9,2[P(C6H5)3]2Cl, das mittels Molmassebestimmungen als Au55[P(C6H5)3]12Cl6 charakterisiert wurde. Ein einfaches Modell, beruhend auf einer Anordnung dichtest gepackter Goldatome, führt zu einem Goldcluster, dessen Aufbau mit der ungewöhnlichen chemischen Zusammensetzung in guter Übereinstimmung ist. Das Mößbauer-Spektrum der Verbindung zeigt vier Sorten von Goldatomen: einen metallischen Anteil (Au13-Kern), durch P(C6H5)3-bzw. Cl-Liganden Koordinierte Au-Atome, sowie unkoordi-niertes Oberflächengold. Mit Brom und lod läß sich der Komplex zu (C6H5)3PAuCl, (C6H5)3 PAuBr(I) und metallischem Gold abbauen. Die Thermolyse bei 50°C führt quantitativ zu [(C6H5)3P]2AuCl und Gold.
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    Berichte der deutschen chemischen Gesellschaft 114 (1981), S. 3655-3666 
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Cyanamidium Salts: Their Formation and Molecular StructureThe hexachloroantimonate 6a, is prepared by methylation of di-tert-butylcarbodiimide. According to an X-ray analysis, 6a is not a carbodiimidium salt 1) but a cyanamidium salt with C2ν symmetry of the molecular frame. the cyanamidium salts 6a - j, are prepared either by alkylation of carbodiimides1) or by alkylation of disubstituted cyanamides. Trisubstituted ureas or their thio analogues are not suitable starting materials for the preparation of compounds 6. Reactions of the cyanamidium salts 6 with HCl, water, and diethylamine are described.
    Notes: Das durch Methylierung von Di-tert-butylcarbodiimid erhältliche Hexachloroantimonate 6a liegt nach einer Röntgenstrukturanalyse nicht als Carbodiimidium-1), sondern als Cyanamidiumsalz mit C2ν-Symmetrie des Molekülgerüstes vor. Die Cyanamidiumsalze 6a - j werden außer durch Alkylierung von Carbodiimiden 1) auch durch Alkylierung von disubstituierten Cyanamiden erhalten. Trisubstituierte Harnstoffe oder Thioharnstoffe sind keine geeigneten Ausgangsverbindungen zur Darstellung der salze 6. Es werden Umsetzungen der cyanamidiumsalze 6 mit HCl, Wasser und Diethylamin beschrieben.
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    Berichte der deutschen chemischen Gesellschaft 114 (1981), S. 3674-3683 
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Transition metal Activated Organic compounds, X: Synthesis and Properties of all-α-Poly(N-methylpyrroles)all-α-Poly(N-methylpyrroles) with 2 - 6, 8 and 16 pyrrole units (2 - 8) were synthesized by lithiation of N-methylpyrrole, subsequent reaction with transition metal halides (best yields with NiCl2 as a rule) and repetitions of these processes. These compounds are surprisingly sensitive to heat and light.
    Notes: all-α-Poly(N-methylpyrrole) mit 2 - 6, 8 und 16 Pyrroleinheiten (2 - 8) wurden durch Lithiierung von N-Methylpyrrol, Umsetzung mit Übergangsmetallhalogeniden (beste Ausbeute meist mit NiCl2) und Wiederholungen dieser Prozesse synthetisiert. Diese Verbindungen sind überraschend empfindlich gegen Hitze und Licht.
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    Berichte der deutschen chemischen Gesellschaft 114 (1981), S. 3667-3673 
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Transition Metal Activated Organic Compounds, IX: Synthesis of Polyfurans by Organometallic Oxidative Coupling2,2′- (2a) and 3,3′-bifuran (3), hitherto only accessible by ring-forming syntheses in small yields, and the unknown compounds all-α-terfuran (2b) and all-α-quaterfuran (2c) have been prepared by convenient ring-Connecting syntheses in 85, 46, 16, or 53% yield, respectively. Lithiation of 2a and subsequent reacting with iodine afforded 5-iodo-2,2′-bifuran (6b, 46%). According to competition experiments acidity against n-butyllithium is increasing in the sequence furan 〈 2a, 〈 2b.
    Notes: 2,2′ - (2a) und 3,3′-Bifuran (3), bisher nur durch ringbildende mehrstufige Synthesen in geringer Ausbeute zugänglich, sowie die noch nicht beschriebenen Verbindungen all-α-Terfuran (2b) und all-α-Quaterfuran (2c wurden durch leicht durchführbare ringverknüpfende Synthesen in 85, 46, 16 bzw. 53proz. Ausbeute erhalten. Lithiierung von 2a und Umsetzung mit Iod führte zu 5-Iod-2,2′-bifuran (6b. 46%). Durch Konkurrenzversuche wurde ansteigende Acidität gegen n-Butyllithium in der Reihe Furan 〈 2a 〈 2b festgestellt.
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    Berichte der deutschen chemischen Gesellschaft 114 (1981), S. 3684-3690 
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Metal Hydrazides, XIX: Addition of Bis(diethylaluminio)-substituted Amidrazones and Carbohydrazides to NitrilesAmidrazones and carbohydrazides react with two equivalents of triethylaluminium to give bis (diethylaluminio) derivatives 1 and 7, respectively. In contrast to the corresponding mono(diethylaluminio)derivatives or disodium salts, these are capable of addition to nitriles with formation of N1-(aminomethylene)amidrazones(4; 81 - 95%) or N1-acylamidrazones (8 and 9; 56 - 85%), respectively.
    Notes: Amidrazone und Carbohydrazide reagieren mit zwei Äquivalenten Triethylaluminium zu Bis(diethylaluminio)-Derivaten 1 bzw. 7, die sich anders als die entsprechenden Mono(diethylaluminio)-Derivate oder Dinatriumsalze glatt an Nitrile addieren. Man erhält N1-(Aminomethylen)amidrazone (4; 81 - 95%) bzw. N1-Acylamidrazone (8 und 9; 56 - 85%).
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    Berichte der deutschen chemischen Gesellschaft 114 (1981), S. 3737-3739 
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The Formation of Trichlorosulfonium (IV) Hexafluoroarsenate(V)Sulfur reacts with chlorine and arsenic Trifluoride under pressure to give [SCl3]+[AsF6]-. As an intermediate oxidizing substance [AsCI4]+ is identified by spectroscopy. Depolarization-Raman-spectra confirm the assignment made in literature.
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    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Additions of Carboxylic Acid Dianions to α,β-Unsaturated Carbonyl Compounds - Control of the 1,2-/1,4-Regioselectivity by Steric substituent EffectsDilithium carboxylic acid dianions 1 attack α,β-unsaturated aldehydes (2) 1,2-regiospecifically with formation of the unsaturated β-hydroxy carboxylic acids 3/4. Additionally, the addition of the phenylacetate dianion 1a can be conducted to the threo-isomer with high selectivity by reversible reaction. - α,β-Enones (8) add 1 irreversibly in 1,2- and 1,4-position. Depending on the substitution pattern, the whole range from pure 1,2- to pure 1,4-adduct is covered. The influence of the 1-counterion M and of the solvent is significant; the 1,4-portion increases with the complexing effect of M and with the Lewis-basicity of the solvent.
    Notes: Dilithiumcarbonsäure-Dianionen 1 addieren sich an α,β-ungesättigte Aldehyde (2) 1,2-regiospezifisch unter Bildung der γ,δ-ungesättigten β-Hydroxycarbonsäuren 3/4, wobei im falle des Phenylessigsäure-Dianions (1a)die Addition durch reversible Reaktionsführung zu hoher threo -Selektivität gesteuert werden kann. - α,β-Enone (8) nehmen 1 irreversibel in 1,2- und 1,4-Position auf, wobei nach Maßgabe der Substituenten das gesamte Spektrum von reinem 1,2- zu reinem 1,4-Addukt überstrichen wird. Bei gleichbleibendem Substitutionsmuster steigt der 1,4-Anteil mit der komplexierenden Wirkung der Gegenionen von 1 und mit der Lewis-Basizität des Solvens.
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    Berichte der deutschen chemischen Gesellschaft 114 (1981), S. 3725-3736 
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Synthesis of Medium and Large Rings, II: Cyclodecenes and Cyclodecadienes with Functional Groups by Ring Expansion of CyclooctyneThe Diels-Alder adduct 1 from cyclooctyne and diethyl 3,4-furandicarboxylate gives by photolysis and subseqent thermolysis of the resulting oxaquadricyclane 2 the β,β′-bridged hexano-oxepin 3. Oxidative cleavage of one C=C double bond of 3 leads to the monocyclic cyclodecenone derivative 5 which can be converted to cyclodecadienes of the type 6 with an anellated butenolide ring. 6a - c, are chiral butadiene derivatives. 6a can be cleaved with acid or base to give the cyclodecenone 7 or the dicarboxylic acid 8.
    Notes: Das Diels-Alder-Addukt 1 aus cyclooctin und 3,4-Furandicarbonsäure-diethylester liefert durch Photolyse und anschließende Thermolyse des Oxaquadricyclans 2 das β,β′-überbrückte hexanooxepin 3. Die oxidative Spaltung einer C=C-Doppelbindung von3 führt zum monocyclischen cyclodecenon 5, das sich zu Cyclodecadienen des Typs 6 mit anelliertem Butenolidring abwandeln läßt. 6a - c enthalten eine chirale Butadien-Struktur. Durch Keton- bzw. Säurespaltung von 6a erhält man das Cyclodecenon 7 bzw. die Dicarbonsäure 8. Mögliche Anwendungen des Verfahrens, das die Einführung von funktionellen Gruppen an vier benachbarten C-Atomen des Zehnringes erlaubt, werden besprochen.
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    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Linear Oligophosphaalkanes, III: Syntheses and stereochemistry of Palladium (II) Complexes of chiral Tetraphosphaalkanes H2-nRnP—[CH2]3 — PR′ — [CH2]m — PR′ — [CH2]3 — PRnH2-n(R, R′, = Me, tBu; m = 2, 3; n = 1, 2)The reaction of the chiral tetradentate ligands L of the title with K2PdCl4 affords the complexes Pd(L)Cl2 (2a - e), which for n = 1 may exist as ten (square pyramidal) or six (square planar coordination geometry) isomers. By suitable choice of the substituents R and size of the chelate rings (m + 3) the number of isomers may be reduced to two or three. The detailed investigation of the complexes 2a - e by means of 31P{1H} NMR spectroscopy offers the possibility to identify their stereochemistry. - Monodeprotonation of 2a (R = Me; m = 3; n = 1) and 2d (R = Me; m = 2; n = 1) by KOH or the OH- Form of anion exchange resin yields the phosphido complexes 3a and d (not isolated). Both compounds are oxidized by air with formation of the phosphanoxidophosphane complexes 4a and d, which exist as two or three configurational isomers with units Pd—P(O)Me—.
    Notes: Die Umsetzung der im Titel genannten vierzähnigen Liganden L mit k2PdCl4 liefert die Komplexe Pd(L)Cl2(2a-e)w, die für n = 1 in Form von zehn (quadratisch pyramidale Ligandenanordnung) bzw. sechs (planare Koordinationsgeometrie) Konfigurationsisomeren vorliegen können. Durch geeignete Wahl der substituenten R und der Chelatringgröße (m + 3) läßt sich die Zahl der Isomeren auf zwei bzw. drei reduzieren. Die detaillierte 31P{1H}-NMR-spektroskopische Untersuchung der Komplexe 2a - e erlaubt die Identifizierung der Stereochemie der Isomeren. - Die durch Monodeprotonierung von 2a (R = Me; m = 3; n = 1) und 2d(R = Me; m = 2; n = 1) mit KOH oder der OH- -Form eines Anionentauschers gebildeten Phosphidokomplexe 3a and d werden durch Luftsauerstoff zu den phosphanoxidophosphan-komplexen 4a und d oxidiert, bei denen zwei bzw. drei Konfigurationsisomere mit P-gebundenen Phosphanoxido-Einheiten Pd—P(O)Me— vorliegen.
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  • 76
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    Berichte der deutschen chemischen Gesellschaft 114 (1981) 
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
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  • 77
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    Berichte der deutschen chemischen Gesellschaft 129 (1996), S. 259-262 
    ISSN: 0009-2940
    Keywords: Halide complexes of diiodacetylene ; Crystal structures ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Complexes of Halide Ions with Diiodoacetylene. The Crystal Structures of PPh4[X(I-C≡C-I)2] with X = Cl, Br, IThe complexes PPh4[X(I-C≡C-I)2] with X = Cl (1), Br (2), and I (3) have been prepared from the phosphonium salts PPh4X and 1-C≡C-I in dichloromethane solutions. 1-3 form colourless crystals, which according to crystal structure analysis crystallize isotypically in the space group P421m with two formula units per unit cell. The diiodacetylenes are coordinated by the halide ions X- in a distorted tetragonal fashion, the I-C≡C-I molecules being in μ2-bridging function. Thus, a polymeric anionic network [X(I-C≡C-I)2]nn- with a layered structure results.
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  • 78
    ISSN: 0009-2940
    Keywords: 2-(2-Pyridyl)phosphinines ; 2,2′-Biphosphinines ; Transition metals ; Biphosphinine chelates ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The synthesis and coordination chemistry of 2-(2-pyridyl)-phosphinines and 2,2′-biphosphinines are reviewed. A noteworthy series of homoleptic complexes of 4,4′,5,5′-tetramethyl-2,2′-biphosphinine (tmbp) with Cr(0), Mo(0), Wo(0) and Ni(0) are described. A [Cu(bpy)(tmbp)]+ cationic polymer has been characterized by X-ray analysis. Ruthenium, manganese and rhenium chelates were also obtained. With Mn2(CO)10, a (tmbp)-Mn2(CO)6 complex is formed where tmbp acts as an eight electron donor.
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  • 79
    ISSN: 0009-2940
    Keywords: Transition-metal indium complexes ; Nickel-indium bonds ; Intramolecular Lewis base adducts ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The reaction of InBr/InBr3 or InBr/BrIn[(CH2)3NMe2]2 with the transition metal dimers [L(CO)nM]2 {L = CO, Cp, C5H4[(CH2)2NMe2]; M = Fe, Co, Ni; n = 1-3} in THF or dioxane gives in almost quantitative yield the transition metal indium complexes L(CO)nM—InBr2(Do) (Do = THF, NC7H13) and L(CO)nM—In[(CH2)3NMe2](Br) respectively. The new compounds were characterized by elemental analysis, infrared v(CO) spectroscopy, NMR, and mass spectrometry. An X-ray single crystal structure determination of (η5-C5H5)(CO)-Ni-InBr2(NC7H13) (1a) revealed a short Ni-In bond of 246.3(1) pm.
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  • 80
    ISSN: 0009-2940
    Keywords: {[ω-(Phosphanyl)alkyl]cyclopentadienyl}cobalt(I) ; Cobalt complexes ; Bidentate ligand ; Alkynes ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: An improved synthesis of [(2-phosphanylethyl)cyclopenta-dienyl]cobalt(I) chelate complexes is presented, in which the paramagnetic chloride 3 is a precursor of the ethene complex 4. The latter readily undergoes ligand exchange reactions which in the case of bidendate reagents (1,5-cyclooctadiene, 1,2-bis(diisopropylphosphanyl)ethane, 2,2′-bipyridine, nor-bornadiene) cause a decomplexation of the phosphane arm at room temperature with formation of 7, 5, 6, 8. The ethene ligand in 4 can be replaced by alkynes under equally mild reaction conditions (formation of 9, 11 - 16). The reaction with ethyne results in the formation of vinylidene complex 10. The yields of the reactions with nonaromatic alkynes could be improved by treating 3 with the alkyne in the presence of sodium amalgam. The unsubstituted vinylidene complex 10 and its tert-butyl derivative 17 were obtained by this route in 38 and 40% yield, respectively.
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  • 81
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    Berichte der deutschen chemischen Gesellschaft 129 (1996), S. 355-359 
    ISSN: 0009-2940
    Keywords: Aluminium compounds ; Gallium compounds ; Indium compounds ; Trimethylfluoro metalates ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Cesium-Fluorine Four-Membered Rings as Structural Motive in Cesium Triorganofluoro Metalates of Group 13The reactions of AlMe3, GaMe3, and InMe3 with CsF in acetonitrile furnish the corresponding trimethylfluoro metalates Cs[Me3MF] (1: M = Al, 2: M = Ga, 3: M = In). The salt-like compounds 1 - 3 were characterized by NMR, IR, and MS techniques as well as by X-ray structure analysis. Cs2F2 four-membered rings are the structure-dominating units in all three compounds. Compound 1 consists of puckered layers of weakly associated Cs2F2 rings parallel to (100), while the four-membered rings in 2 form infinite ladder-type chains. The Cs-F rings in 3 build up a heterocubane with a Cs4F4 core by ring stacking.
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  • 82
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    Berichte der deutschen chemischen Gesellschaft 129 (1996), S. 381-384 
    ISSN: 0009-2940
    Keywords: Alanes, tert-butoxy- and bis(tert-butoxy)- ; Gallanes, tert-butoxy- and bis(tert-butoxy)- ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The crystal structures obtained by X-ray methods of (tert- butoxy)alane and -gallane (tBuOMH2) are isotypic and are composed of discrete centrosymmetric dimers. The dimers arise from almost symmetrical Al—O—Al [1.810(3), 1.815(3) Å] and Ga—O—Ga [1.902(9), 1.908(9) Å] bridges forming a central rhombohedral four membered M2O2 cycle [O—Al—O 81.0(2)°, O—Ga—O 78.6(5)°] with the metallic atoms in a distorted tetrahedral environment. When one of the hydride ligands on the metals is further substituted by tert-butoxy, the formation of (tBuO)2AlH and (tBuO)2 GaH is observed. These two compounds crystallize in different lattices and space groups, but they are nevertheless very similar in their structure: the centrosymmetric M2O2 cycle is maintained [Al—O 1.817(3), 1.817(3) Å; Ga—O 1.904(4), 1.907(4) Å] As expected, the terminal Al-O [1.675(3) Å] and Ga—O [1.783(4) Å] distances are considerably shorter than the bridging ones.
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  • 83
    ISSN: 0009-2940
    Keywords: Germanium ; Trigermanes ; Germylene ; Trapping reactions ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Treatment of hexa-tert-butylcyclotrigermane (3) with CCl4, Br2, and I2 furnishes the correspondingly substituted 1,3-dichloro- (4), 1,3-dibromo- (5), and 1,3-diiodotrigermanes (6). The symmetries of the molecules of 5 and 6 are very similar (point group C1) revealing gauche-anti conformations and different Ge—Ge bond lengths. However, while 5 crystallizes as a racemate, 6 forms a conglomerate of enantiomerically pure crystals. The X-ray structure analysis of the 1,3-dimethyltrigermane (7) derivative, derived from 6 by a sequence of metalation and methylation reactions, reveals more symmetrical molecules of the point group C2 which also crystallize as a racemate. Irradiation of 3 leads to tetra-tert-butyldigermene (8) and di-tert-butylgermylene (9) which could be trapped by addition and cycloaddition reactions with selenium, tellurium, and 3,5-di-tert-butyl-1,2-benzoquinone.
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  • 84
    ISSN: 0009-2940
    Keywords: Carbene complexes ; Metallacycles ; Claisen rearrangement ; Cascade reaction ; Cyclopentenones ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The cationic ferracyclic carbene complexes 1 react with carbon nucleophiles like lithium enolates and organocuprates to give the corresponding 4-substituted 1, (3E)-diene tricarbonyl-iron complexes 6 and 9. The reaction is thought to proceed by initial attack on the allyl terminus and subsequent ferra Claisen-Ireland rearrangement of the intermediate (η2 alkene)carbene complex 4. This rationale is supported by the isolation and characterisation of analogous aminooxocarbene derivatives 8. With sterically demanding enolates products 6 are formed in diastereomeric ratios of up to 90:10, thus demonstrating the inductive power of the chiral metallacycle in 1. Lithium acetylides as carbon nucleophiles react with 1 according to a novel cascade to give regio- and stereospecifically 2,5,5-trisubstituted-cyclopentenones 10 suggesting a concerted formation of four C=C bonds together with a CO insertion and a formal carbene transfer step.
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  • 85
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    Berichte der deutschen chemischen Gesellschaft 129 (1996), S. 435-440 
    ISSN: 0009-2940
    Keywords: Zinc complexes ; Sulfur and nitrogen ligands ; Structure and bonding ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The zinc complex chemistry of the tridentate thiol ligand N- (2-mercaptophenyl)(2-picolyl)amine (MPPAH) differs considerably from that of the aliphatic analogue N-(2-mercaptoethyl)(2-picolyl)amine reported previously. This is due to the lower basicity and hence bridging tendency of its aromatic thiolate function. With zinc salts of oxo anions the 1:1 complexes (MPPA)ZnX (1a-c: X = ONO2, OAc, OBz) are formed which according to spectroscopic data are monomeric while the halide (MPPA)ZnBr (2) seems to be polymeric. In the absence of coordinating anions the monomeric 2:1 complex (MPPA)2Zn (3) results which according to a crystal structure determination contains tetrahedral zinc coordinated by one MPPA ligand in a tridentate fashion while the other is only monodentate and sulfur-bound. A similar N2S2 coordination can be deduced for the 1:1:1 complex (MPPA)Zn(STrt) (4) resulting from ZnEt2, MPPAH and triphenylmethanethiol.
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  • 86
    ISSN: 0009-2940
    Keywords: Phosphenium cations ; Silver complexes ; 31P, 109Ag NMR shift correlation ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Reaction of bis(diisopropylamino)phosphenium triflate (1[CF3SO3]) with silver salts AgY [Y- = CF3CO2- (2a), CF3-SO3- (2b), CH3CO2- (2c)] affords neutral complexes [{(iPr2N)2(Y)P} Ag(OSO2CF3)] (3a-c). While 3a, c are stable up to ambient temperature, 3b is only stable at low temperature and in equilibrium with the cation 1. The constitution of 3a-c was derived from multinuclear (1H, 13C, 31P, 109Ag) NMR spectra. Compound 3a was further studied by X-ray single-crystal diff ractommetry which showed the presence of dimeric units with μ2-bridging triflate ligands and three-coordinate silver atoms with a planar T-shaped coordination geometry. Reaction of 4-chloro-1,3-bis(2,6-dimethylphenyl)-1,3,2-diazaphospholenium triflate (4[CF3SO3]) with 2a, c affords equilibrium mixtures whose 31P- and 109Ag-NMR spectra suggested the presence of silver complexes 5a, c with constitutions similar to those of 3a, c besides unreacted cation 4. No reaction was observed between 4[CF3SO3] and 2b. A common mechanism accounting for the different outcome of the individual reactions will be discussed.
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  • 87
    ISSN: 0009-2940
    Keywords: Nitroxide radical ; Silver(I) complex ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The reaction of 2,5-dihydro-4,5,5-trimethyl-2,2-di-2-pyridyl-imidazole-1-oxyl (L) with AgSbF6 gives the complex [Ag2L2]2+[SbF6-]2 which was characterized by X-ray diffraction. - The complex (a biradical) forms a four-membered ring with two Ag(I) ions and two imine nitrogen atoms of the imidazolines with a relatively short Ag - Ag distance [2.839(2) Å]. Magnetic measurements indicate that two nitroxide radicals are slightly coupled.
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  • 88
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    Berichte der deutschen chemischen Gesellschaft 129 (1996), S. 581-584 
    ISSN: 0009-2940
    Keywords: Crown thioether ; Silver(I) complex ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The crown thioether 3 with the novel diisopropylidene building block was synthesized by an S′N cyclization reaction of 2,7-dichloro-2,7-dimethylocta-3,5-diyne (1) with 3-thia-pentane-1,5-dithiol (2). Ligand 3 shows all the sulfur centers in exodentate positions. Reaction of 3 with Ag1 triflate and triphenylphosphane yielded the tetrahedral complex 4, which shows unique spectroscopic data in solution. Crystallization furnished two different crystal forms (4a and 4b). Both are different conformers which are stable in the solid state. 4a exhibits a crown-like structure of the thioether ligand with cisoid S—C—C—S chains. To our knowledge 4b is the first silver(1) complex with a crown thioether retaining the tran-soid S—C—C—S conformation in the metal complex.
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  • 89
    ISSN: 0009-2940
    Keywords: Carbene complexes ; Organoiron compounds ; Metallacycles ; Rearrangements ; C — C coupling ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Cationic metallacyclic carbene complexes of iron and cobalt bearing a terminal η3-allyl ligand are susceptible to nucleophilic attack at different sites depending on the particular set of substituents, the central metal fragment, and the nucleophile. Attack of enolates, cuprates, acetylides, or heteroatom nucleophiles like phosphanes at the metallacyclic perimeter of the iron complexes 18 provides an easy access to unsaturated organic products like 1,2- or 1,3-dienes, δ-lactones, and functionalized cyclopentenones through novel rearrangement or cascade pathways. Synthetic applications are described; factors governing reactivity/selectivity are discussed; X-ray analytical structures of novel metallacycles are provided.
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  • 90
    ISSN: 0009-2940
    Keywords: Bis(phosphonio)isophosphindolide cations ; Silver complexes ; 31P NMR ; 109Ag NMR ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The outcome of reactions of bis(phosphonio)isophosphindolide salts 1[X] and 6[X] (X- = Cl-, Br-, CF3SO3-) with silver salts AgY (Y- = CF3SO3-, CF3CO2-, CH3CO2-, 1/2 SO4-) depends strongly on the available anions X, Y. If X-, Y- = CF3SO3-, both mononuclear and dinuclear silver complexes are formed which exhibit either μ1,μ1(P) or μ2,η1(P) coordination of the cations 1, 6 to one or to both metals. In solution, dynamic equilibria between both types of products and free 1, 6 were detected by 31P-NMR spectroscopy. Mononuclear (4a, 7) and dinuclear (5a, 8) complexes were isolated as solvates with CHCl3 or THF. If X-, Y- = CF3CO2, only equilibrium mixtures between the free ligands and silver complexes and no isolable products were obtained. 31P-NMR investigations revealed a preference for the formation of dinuclear complexes. Anion metathesis and precipitation of AgX were observed for X- = Cl-, Br-. No coordination of 1, 6 to Ag+ took place in the case of Y- = CH3CO2-, SO42-. The formed complexes were characterised in solution by 31P- and in part by 109Ag-NMR spectroscopy. Complexes 7, 8 were further studied by single crystal X-ray diffraction which revealed the presence of a THF molecule coordinated to silver in both cases. The μ2-coordinated cation 1 is the only bridging ligand in 8, whereas the presence of additional μ2-CF3CO2 ligands was deduced from the results of 31P,31P EXSY measurements in the case of the trifluoroacetato complexes.
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  • 91
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    Berichte der deutschen chemischen Gesellschaft 129 (1996), S. 367-379 
    ISSN: 0009-2940
    Keywords: Arsaalkene chemistry ; Arsaalkynes ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The present article gives an account of the synthesis and structure as well as the spectroscopic and chemical properties of arsaalkenes R1As=CR2R3 and arsaalkynes RC≡As. Arsaalkenes are significantly less stable and more reactive than the corresponding phosphaalkenes. Only one kinetically stabilized arsaalkyne has been described so far.
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  • 92
    ISSN: 0009-2940
    Keywords: Tetraindane(4) ; Indium(I) ; Co—Co bond ; Indium alkyl bridge ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: tetrahedra-Tetrakis[tris(trimethylsilyl)methyl]tetraindane(4) (1) reacts with octacarbonyldicobalt to yield two products, depending on the stoichiometric ratio of the starting compounds: By replacement of one bridging carbonyl group a dicobalt monoindium derivative 2 is formed, which contains a Co—Co bond [256.81(5) pm] bridged by one carbonyl and one monoalkylindium group. While 2 is a monomer in benzene solutions, it dimerizes in the solid state by an interaction of the oxygen atom of the bridging carbonyl group to the coordinatively unsaturated In atom of a second molecule across a center of symmetry. Another compound (3) is formed by the replacement of both bridging carbonyl ligands, which exhibits a strongly distorted Co2In2 tetrahedron with normal Co—In bond lengths of 253.44(6) pm, but long Co—Co [280.14(6) pm] and In—In distances [336.18(6) pm].
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  • 93
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    Berichte der deutschen chemischen Gesellschaft 129 (1996), S. 419-425 
    ISSN: 0009-2940
    Keywords: Cyclobutene ; Bicyclobutane ; 1,3-Butadiene ; Phosphorus substitution ; Relative energies ; Quantum chemical investigations ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Cyclobutene, bicyclobutane, and 1,3-butadiene are valence isomers within the concept of the Woodward-Hoffman rules. According to thermochemical considerations and in agreement with energy optimized quantum-chemical calculations at the ab initio RHF and MP2/6-31G(d,p) levels bicyclobutane is the least and 1,3-butadiene the most stable valence isomer. Phosphorus substitution exerts a considerable effect on the relative stabilities of the various valence isomers. Bicyclobutanes containing phosphorus atoms in the bridgehead positions are considerably more stable than the other phosphorus-substituted valence isomers. This conclusion was confirmed by an analysis of the natural bond populations.
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  • 94
    ISSN: 0009-2940
    Keywords: Paramagnetic planar complexes of NiII ; Phosphinic amidato ligands ; NMR spectroscopy ; Magnetic measurements ; Vis spectra ; Crystal structure ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: After a brief review of previous work the results of the metathesis reaction between Ni(dme)Br2 and R2P(O)NR′Li [R = tBu, iPr, Ph; R′ = Et, Pr, iPr, (±)-sBu, tBu, tPen, Cy, Ph, (-)-α-methylbenzyl = Mb, 1-adamantyl = Ad] are reported. Complex formation occurred only with lithiated amides of tert-butylphosphinic acid, and bischelates [tBu2P(O)NR′]2Ni were obtained when R′ = sBu, Mb, tPen, Ad (1d - g). With R′ = Et, Pr bischelation was incomplete. Vis spectroscopy showed the paramagnetic compounds 1d - f to be planar in the solid state but tetrahedral in solution. 1g is tetrahedral in both phases. The planar structure of 1f was confirmed by X-ray single-crystal analysis (monoclinic, space group P21/n). The magnetic moments μeff of 1d, e, g are ca. 3.2-3.5 μB in both phases and the Curie-Weiss law is obeyed in the range 293-183 K. The same is valid for dissolved 1f. The μeff values of solid 1f are however, strongly temperature-dependent, varying from 1.38 to 0.55 μB (300-90 K). NMR data (31P, 1H, 13C) are reported. Obviously, a favorable combination of electronic and steric factors of substituents R and R′ produces with ligands [R2P(O)NR′]- the donor quality necessary for bischelation as well as the singular field strength required for the formation of planar paramagnetic species. As the combination of paramagnetism and planarity is bound to the solid state, lattice energy effects may be finally decisive for this unique constellation of tetracoordinated NiII complexes.
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  • 95
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    Berichte der deutschen chemischen Gesellschaft 129 (1996), S. 575-580 
    ISSN: 0009-2940
    Keywords: Molybdenum complexes ; Peroxo complexes ; Catalysis ; Olefin epoxidation ; Proton transfer ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: NMR studies of the reaction of complexes of the type (L-L)MoO(O2)2 (L - L= bidentate ligand) with strong Brønsted and Lewis acids prove that protons are transferred preferentially to an η2-peroxo and not to the oxo ligand. This behavior in proton transfer reactions is one critical point of the catalytic activity of such complexes in olefin epoxidation. EH calculations on the model complex (NH3)2MoO(O2)2 support the spectroscopic investigations.
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  • 96
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    Berichte der deutschen chemischen Gesellschaft 129 (1996), S. 897-901 
    ISSN: 0009-2940
    Keywords: Gallium-Gallium bond ; Isocyanide insertion ; 1,4-Diazabutadiene derivatives ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Tetrakis[bis(trimethylsilyl)methyl]digallane(4) (1) reacts with tert-butyl or aryl=isocyanides [aryl = phenyl, o-methylphenyl, o-methoxyphenyl, p-methoxyphenyl) by a twofold insertion of the central carbon atoms into the Ga-Ga bond and formation of C-C single bonds. 1,4-Diazabutadiene derivatives bound to two R2Ga groups are formed (2-6), which in contrast to an aluminium analog exhibit only weak interactions between the imine nitrogen atoms and the coordinatively unsaturated gallium atoms as indicated by NMR spectroscopy and the long Ga-N distances in the molecular structures of three products: 2 (R = C6H5), 4 (R = o-MeOC6H4), and 6 (R = CMe3).
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  • 97
    ISSN: 0009-2940
    Keywords: Cadmium sulfide ; Paired photoelectrolysis ; γ,δ-Unsaturated amines ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Irradiation of methanolic cadmium sulfide suspensions in the presence of Schiff bases and cyclopentene opens an easy access to new γ,δ-unsaturated amines. Their formation can be described as a kind of paired photoelectrolysis induced by the photogenerated electron-hole pair trapped at reactive surface sites of CdS. At the reductive site the imine is converted to an α-aminobenzyl radical by a proton-coupled electron transfer, while at the oxidative site cyclopentene is transformed to the cyclopentenyl radical through deprotonation of the intermediate radical cation. C-C coupling of these radicals affords the addition products. Competitive dimerisation of the radicals produces hydrodimers of the imines and dehydrodimers of the olefin, as demonstrated in the case of 1-phenylcyclohexene. Using optical active imines, we found no significant diastereoselectivity. In the absence of an olefin the alcoholic solvent was added to the imine. The molecular structure of one hydrodimer was resolved by X-ray analysis. When CdS/Pt was used as photocatalyst, hydrolysis products of the imine were formed, suggesting involvement of an intermediate OH radical.
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  • 98
    ISSN: 0009-2940
    Keywords: Lanthanum complexes ; Neodymium complexes ; Erbium complexes ; Pyrazolate, 3,5-di-tert-butyl-, complexes of ; Pyrazolate, 3,5-diphenyl-, complexes of ; 1,2-Dimethoxyethane, complexes of ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The complexes [Ln(Ph2pz)3 (DME)2] and [Ln(tBu2pz)3 (DME)] (Ln = La, Nd, Er; Ph2pzH = 3,5-diphenylpyrazole; tBu2pzH = 3,5-di-tert-butylpyrazole; DME = 1,2-dimethoxyethane) have been prepared by reaction of the lanthanoid metal with bis(pentafluorophenyl)mercury and the pyrazole in DME. The molecular structures of [Er(Ph2pz)3 (DME)2] (3) and [Nd(tBu2pz)3 (DME)]∞ (5) have been determined by X-ray diffraction. Complex 3 has nine-coordinate Er with three chelating Ph2pz ligands and one chelating and one η1-bound DME. There is a trigonal prismatic arrangement of the oxygen donors and the centres of the N - N bonds. 5 was found to be a linear polymer with transoid DME ligands bridging Nd(tBu2pz)3 units in a novel manner. The centres of the N - N bonds (which are essentially coplanar with Nd), and the oxygen donor atoms adopt an arrangement intermediate between trigonal-bipyramidal and square-pyramidal [O - Nd - O 153.5(2)°].
    Additional Material: 5 Ill.
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  • 99
    ISSN: 0009-2940
    Keywords: Steroids ; Androsta-1,4-diene-3,17-dione ; Conjugate addition ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: By a variation of the nature of the reagent system conjugate addition to the cross-conjugated steroidal dienone 1 occurs selectively either at C-1 or at the sterically hindered C-5. With Me3Al or Me4AlLi in the presence of catalytic amounts of Cu1 salts, a high regioselectivity (up to 97:3) in favour of position 1 is achieved. Application of ate complexes of aluminium and titanium in the presence of Ni(acac)2 as catalyst, however, leads to a reversal of the regioselectivity in favour of position 5 (up to 11:89). Aluminium and titanium ate complexes are efficient reagents in the Ni(acac)2-catalysed conjugate addition to sterically hindered enones.
    Additional Material: 2 Tab.
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  • 100
    ISSN: 0009-2940
    Keywords: M2P2 tetrahedral complexes ; Phosphido ligand complexes as intermediates ; Ni2P4O distorted prismane framework ; CO incorporation ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Complexes with Metal-Phosphorus Triple Bonds as Possible Intermediates in the Reactions between Chlorophosphinidenes and Metalates of Various Transition MetalsThe reaction of [{M′(CO)5}2PCl] (M′ = Cr, W) with various metalates ([Cp′Mo(CO)3]-, [Cp * Ni(CO)]-, [Cr2(CO)10]2-) yields the M2P2 tetrahedral complexes [(MLn)2(μ,η2- P2){M′(CO)5}2] (MLn = Cp*Ni, M′= Cr (1), W (2); MLn = Cp′Mo(CO)2, M′ = Cr (4); Cp* = η5-C5Me5, Cp* = η5C5H3tBu2) and the cyclo-P4 compound [{Cr(CO)4}(η4-P4){Cr(CO)5}4] 6. As side products the distorted prismane [(Cp*Ni)2{μ4,η4-(P2-O-P2)}{W(CO)5}2] 3 and the diphosphino-methanone complex [{Cp′Mo(CO)2}2{μ4η2-PC(O)P}-{Cr(CO)5}2] 5 are formed. The complexes are characterised by NMR, IR, MS, and X-ray structure analysis (1-5). Studying the reaction pathway provided evidence of phosphido intermediates of the type [LnM≡P→M′Ln].
    Additional Material: 4 Ill.
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