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  • Inorganic Chemistry  (1,334)
  • 1995-1999  (602)
  • 1990-1994  (732)
  • 1950-1954
  • 1996  (602)
  • 1992  (732)
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  • 1995-1999  (602)
  • 1990-1994  (732)
  • 1950-1954
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  • 1
    ISSN: 0009-2940
    Keywords: Metallocene complexes, group-4 ; Metallocene cations hydrocarbyl ; Dinuclear complexes main-group ; transition-metal ; Carbometallation ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The methylzirconocene cation, employed as the [Cp2ZrCH3(THF)]+BPh4- reagent 1a reacts with (R′C≡C)2SiR2 substrates (6a-d) by means of carbometallation of an alkynyl group to yield the mixed metal ring systems 8a-d, containing both a 1,1-disubstituted μ-alkenyl and an alkynyl bridge between zirconium and silicon (e.g. shown by X-ray crystal structure analyses of complexes 8a and 8c). A similar addition reaction takes place upon treatment of the (butadiene)zirconocene/tris(pentafluorophenyl)-borane 1:1 addition product 9 with (CH3-C≡C)2Si(CH3)2 (6c) to give 10. Here the incipient alkyl zirconocene cation character of the metallocene/borate betaine complex 9 shows up in the alkynyl silane carbometallation reaction.
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  • 2
    ISSN: 0009-2940
    Keywords: Arsaalkenes ; Carbonyliron complexes ; Arsete, 1,2-dihydro- ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Reaction of equimolar amounts of thiuronium salt [(Me2N)2C-SMe]I (1, with LiAs(SiMe3)2 · 2 THF (2) afforded arsaalkene Me3SiAs=C(NMe2)2 (3). Combination of 3 with (η5-C5Me5)(CO)2 FeBr led to the formation of (η5-C5Me5)(CO)2-FeAs=C(NMe2)2 (4). Reaction of the latter with dimethyl fumarate gave the 1,2-dihydroarsete (η5-C5Me5)(CO)2-Fe (6). Compounds 3, 4, and 6 were characterized by means of spectroscopy (IR, 1H, 13C{1H}, 29Si{1H} NMR and mass spectrometry). The molecular structures of 4 and 6 were determined by X-ray diffraction analysis.
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  • 3
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 129 (1996), S. 237-242 
    ISSN: 0009-2940
    Keywords: Hemiporphyrazines ; Macrocyclic bisdienes and bisdienophiles ; Nickel complexes ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The bisdienophilic (hemiporphyrazinato)nickel complexes 1a-d bearing various alkoxy groups were synthesized from diiminoisoindoles 9a-d, diaminopyridines 10a, d, and nickel acetate. Reaction of 1a-d with an excess of pentaene 3 delivered the macrocyclic bisdienes 2a-d. The hemiporphyrezines were characterized by 1H- and 13C-NMR spectroscopy. The NMR spectra of the 1,6,16,21-tetrabutoxy-substituted compounds 1b and 2b are discussed with respect to the presence of syn/anti isomers.
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  • 4
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    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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  • 5
    Electronic Resource
    Electronic Resource
    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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  • 6
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 129 (1996), S. 799-805 
    ISSN: 0009-2940
    Keywords: Bis(lithiomethyl)silanes ; 1,3-Dilithiosilanes ; Polylithioalkyls ; 1,3-Disilacyclobutanes ; (Stannylmethyl)silanes ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The first high yield preparation of non π-stabilized bis(lithio-methyl)silanes was performed by the reductive cleavage of C-S bonds with electron transfer reagents. Bis[(phenylthio)-methyl]silanes synthesized by the reaction of dichlorosilanes with [(phenylthio)methyl]lithium were transformed to the corresponding bis(lithiomethyl)silanes 7 by reaction with lithium naphthalenide (LiC10H8) or lithium p,p′-di-tert-butyl-biphenylide (LiDBB) as an electron transfer reagent and were characterized by their reaction with Bu3SnCl. The C-S bonds of bis[(phenylthio)methyl]silanes can be cleaved selectively making possible the introduction of two different groups. - The silicon atom plays a central role in the reactivity of the presented structural types. The bis(lithiomethyl)silanes are used as new building blocks for the preparation of organosilanes, Si-H-functionalized organosilanes, and 1,3-disilacyclobutanes containing SiCH2Si structural units.
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  • 7
    ISSN: 0009-2940
    Keywords: Polymer-bound catalyst ; Enantioselective hydrogenation ; Rhodium complexes ; Interphases ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: A new polymer-attached rhodium catalyst on a polyethylene oxide-grafted styrene matrix (TentaGel) is described. The corresponding anchor molecules were prepared by starting from different Boc-protected chiral pyrrolidinebis(phosphane)Pd complexes. The crystal structure of [3R,4R)-N-(4-carboxybutanoyl)-3,4-bis(diphenylphosphanyl)pyrrolidine-P,P′]-diiodopalladium (1c) was determined. The formation of an amide bond between TentaGel and anchor molecules resulted in polymer-bound Pd bisphosphane complexes. De-complexation of the Pd with cyanide and reaction of the free polymeric ligand with [Rh(COD)2]BF4 led to the active hydrogenation catalyst. The influence of different solvents on the swelling volume and the catalytic behavior was tested. The polymer-bound rhodium complex [(3R,4R)-N-(1,5-dioxo-5-TentaGel-amino-pentyl)-3,4-bis (diphenylphosphanyl)pyrrolidineP,P′] (1,5-cyclooctadiene)rhodium tetrafluoroborate (7) has about the same catalytic activity and enantioselectivity as the homogeneous complex [(3R,4R)-N-(tert-butoxycarbonyl)-3,4-bis(diphenylphosphanyl)pyrrolidine-P,P′] (1,5-cyclooctadiene)rhodium tetrafluoroborate (9) in the same solvent mixture. It is possible to reuse 7 once, then it abruptly loses activity. This behavior remains to be clarified.
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  • 8
    ISSN: 0009-2940
    Keywords: Borate lithium (dimethylamino)trihydrido- ; TMEDA complex ; Dioxane complex ; 12-Crown-4 complex ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Li(Me2NBH3) (1) was prepared by deprotonation of Me2NH BH3 with LiBu and its solubility determined in various solvents. Compound 1 is unstable in most ethereal solvents and decomposes in a reversible reaction into LiH and Li-(Me2N—BH2—NMe2—BH3) (2). Five solvates of 1 were characterised by X-ray structure analysis. Li(Me2NH3) · TMEDA is a dimer in the solid state, and two units are connected to one another by B—H…Li bonds. The crystal structure of Li(Me2NBH3) · 0.5 dioxane is represented by layers consisting of tetrameric Li(Me2NBH3) units connected via dioxane molecules. Each Li atom is coordinated to one oxygen atom, one nitrogen atom, and two hydrogen atoms. Also Li(Me2NBH3) · 0.5 O2C3H6 forms an extended layer, however with pentacoordinated Li atoms which bear one oxygen, one nitrogen, and three hydrogen atoms. A similar layer structure was also found for Li(Me2NBH3) · O3C3H6 where each Li atom is bound to two oxygen atoms of different trioxane molecules, one nitrogen atom, and two hydrogen atoms. Finally, Li(Me2NBH3) · 12-crown-4 retains its molecular integrity in the solid state. Its Li atom is pentacoordinated by four oxygen atoms and one nitrogen atom.
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  • 9
    ISSN: 0009-2940
    Keywords: Phosphanes ; Phosphazanes ; Methyleneamine ; Imidazoles ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Imidazole Derivatives, XVII. - Synthesis and Properties of Dichloro(1,3-dimethyl-2-imidazol-2-ylidenimino)phosphane - a Methylenamino Substituent with Uncommon Donor PropertiesDichloro(1,3-dimethyl-2-imidazol-2-ylidenimino)phosphane (5) is obtained from 1,3-dimethyl-2,3-dihydro-2-trimethylsilyliminoimidazole (4) and PCl3 in almost quantitative yield. Strong PN-π interaction (5B) is revealed by its X-ray structure analysis [P(1)-N(1) 1.579(2) Å]. AlCI3 causes chloride abstraction to give the cationic cyclophosphazane 8 identified by NMR spectroscopy.
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  • 10
    ISSN: 0009-2940
    Keywords: 1,8-Disilylnaphthalene ; Disiloxane ; Disilthiane ; Disilazanes ; Phosphonium bis(silyl)methylide based on 1,8-disilylnaphthalene ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The synthesis, spectroscopic data and molecular structures of heterocycles derived from 1,8-disilylnaphthalene are reported. The key intermediate for the preparation of the title compounds is 1,8-bis[(trifluoromethylsulfonyl)silyl]naphthalene (3), which is prepared from 1,8-bis[(4-methoxyphenyl)silyl]naphthalene (2) by treatment with two equivalents of triflic acid in toluene at -20°C. The resulting silyl triflate is stable only below this temperature and was not isolated. Its reactions with water, ammonia, amines, and sulfane give the corresponding disiloxane, disilazanes and disilthiane. The molecular structure of Si,Si′-(Naphthalene-1,8-diyl)-N-phenyldisilazane (8) was determined by X-ray diffraction. Treatment of 2 with substoichiometric amounts of triflic acid and subsequent reaction of the resulting monosilyl triflate with tert-butylamine gives a related chiral N-tert-butyl-Si-(4-methoxyphenyl)disilazane 10. Its molecular structure was proven by X-ray diffraction. A cyclic phosphonium bis(silyl)methylide (11) was synthesized by a transylidation process using 3 and CH2=P(NMe2)3. The structure of 11 was also determined by X-ray diffraction.
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  • 11
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 129 (1996), S. 527-533 
    ISSN: 0009-2940
    Keywords: Density functional theory ; Electron localization function ; NMR chemical shift tensor ; Transition-metal carbonyl clusters ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Carbon and oxygen chemical shift tensors for bridging and terminal carbonyl ligands in Fe2(CO)9 and Rh6(CO)16 were calculated by sum-over-states density-functional perturbation theory (SOS-DFPT). Agreement with experimental 13C shift tensors is excellent, and 17O shift tensors are predicted. The reduced anisotropy values of the shift tensors for the bridging compared to terminal carbonyl ligands are due to large deshielding contributions to δ33 from non-bonding or bridge-bonding orbitals. Comparison to recent computational results for a series of unusual piano-stool and bent-sandwich group-4 complexes is made. The electronic structures of the clusters are discussed by using plots of electron localization functions (ELF). Bonding electrons within the Rh6 cluster are mainly localized on the unbridged octahedral faces. This leads to a heterocubane-like arrangement of ELF maxima above all octahedral faces (four bridging CO ligands, four M-M 3-center-bonding maxima), in analogy to previous results for B6H62-.
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  • 12
    ISSN: 0009-2940
    Keywords: PC cleavage ; P,P′-Bi(1,3,2,4-diphosphadiboretane), 3,3′-di-tert-butyl-2,2′,4,4′-tetrakis-(tetramethylpiperidino)- ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Photolysis of the 1,3,2,4-diphosphadiboretane (tBuPBtmp)2 (1) in dilute toluene solution yields the bicyclic diphosphadiboretane 2. In concentrated toluene solution or in hexane, however, the P,P′-connected bi(diphosphadiboretane) 4 is also formed implying that the radical [tBuP(Btmp)2P] 3 is the first photolysis product. On further photolysis, 3 and 4 are converted into bicyclic 2 as the final product. Reduction of 4 with sodium-potassium alloy followed by silylation with Me3-SiCl leads to the 1,3,2,4-diphosphadiboretanes (tmpBP-SiMe3)2 and [HP(Btmp)2PSiMe3]2. In contrast to many 1,3,2,4-diboretanes, 4 in the absence of photon or thermal promotion does not react with Cr(CO)5 · THF, Fe2(CO)9, or Pd(PPh3)4. However, a mixture of Cr(CO)5 · THF and 4 on photolysis gives the known complex (tmpBP)2 · 2 Cr(CO)5.
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  • 13
    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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  • 14
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 129 (1996), S. 603-606 
    ISSN: 0009-2940
    Keywords: Ferrocenylboranes ; Tri-l-pyrazolylborate ligands ; Oligometallic complexes ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The reaction of (dibromoboryl)ferrocene (1a) with pyrazole/NEt3 gave the ferrocenyltri-1-pyrazolylborate ligand 2. Its thallium(I) derivative 2-Tl provides the first example of a polymeric structure with bridging tri-1-pyrazolylborate units in the solid state. The trinuclear iron complex 2-Fe, which is related to 1,1′-terferrocene, was obtained by reaction of 2 with FeCl2. The bis(polydentate) ligand 1,1′-ferrocenediyl-bis(tri-1-pyrazolylborate) (3-Li) was prepared from 1,1′-bis-[bis(dimethylamino)boryl]ferrocene (1c) and a mixture of lithium pyrazolide/pyrazole in refluxing toluene/THF. 3-Li reacts with TlNO3 to give the thallium(I) complex 3-Tl.
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  • 15
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 129 (1996), S. 633-638 
    ISSN: 0009-2940
    Keywords: Grignard reagents, α-seleno-substituted ; Kinetic resolution ; Racemization ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: α-Selenoalkyl Grignard reagents 2 are chiral. On reaction with the magnesium chelate 3a of α-benzyloxypropionaldehyde they show significant degrees of kinetic resolution, especially when the reactions are run in CH2Cl2. Under these conditions, racemic 2 was resolved by reaction with 0.59 equivalents of 3a at temperatures below -20°C. The remaining 2 had an enantiomer enrichment of 80-86% e.e. (as found by trapping). Hence, 2 has a considerably higher configurational stability than its lithium counterpart 1.
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  • 16
    ISSN: 0009-2940
    Keywords: Rhodium(I) complexes ; Carboxylate bridges ; Iridium(I) complexes ; Acetato ligands ; Iridium(III) complexes ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: [Rh(μ-O2CCH3)(C2H4)2]2 (3) and analogous carboxylatobis-(olefin)rhodium(I) complexes [Rh(μ-O2CR)(olefin)2]2 (4-6) were almost quantitatively prepared under heterogeneous conditions from [RhCl(C8H14)2]2 (1) or [RhCl(C2H4)2]2 (2) and CH3CO2Na · 3 H2O or RCO2H/NaOH, respectively. The X-ray crystal structure analysis of 3 confirmed the bridging position of the acetato ligands. The synthesis of [Ir(μ-O2CCH3)(C2H4)2]2 (10) was carried out similarly by using [IrCl(C2H4)2]2 (8) and CH3CO2Na · 3 H2O as starting materials. The monoethene complex trans-[Ir(η1-O2CCH3)(C2H4)-(PiPr3)2] (11) was obtained from 10 and PiPr3; it reacted with H2 and HC≡CPh by oxidative addition to give [IrH2(η2-O2CCH3)(PiPr3)2] (12) and [IrH(C≡CPh)(η2-O2CCH3)(PiPr3)2] (14), respectively. Compound 12 was also prepared from [IrH2Cl(PiPr3)2] (13) and CH3CO2Na · 3 H2O. The new bis-(ethene)complexes 3, [Rh(μ-O2CC6H5)(C2H4)2]2 (6) and 10 are catalytically less active than 2 in the reaction of C2H4 and Ph2CN2 and gave as C-C coupling product not only 1,1-diphenylpropene (16) but also mixtures of 16 and 1,1-diphenylcyclopropane (17) in different ratios.
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  • 17
    ISSN: 0009-2940
    Keywords: Amido Complexes ; Manganese Compounds ; Iron Compounds ; Cobalt Compounds ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Syntheses and Crystal Structures of the Amido Complexes [Na(12-Crown-4)2][M{N(SiMe3)2}3] with M = Mn, Fe, and CoThe ionic amido complexes [Na(12-crown-4)2][M[N-(SiMe3)2}3] with M = Mn (1), Fe (2) and Co (3) were prepared by the reaction of M[N(SiMe3)2]2 (M = Mn, Co) and Fe[N-(SiMe3)2]3, respectively, with sodium bis(trimethylsilyl)amide in toluene solution in the presence of 12-crown-4. 1-3 were characterized by IR spectroscopy and by crystal structure determinations. The complexes consist of cations [Na(12-crown-4)2]+ with a sandwich-like structure and anions [M{N(SiMe3)2}3]- in which the metal atoms are planarly coordinate by the three nitrogen atoms of the bis(trimethylsilyl)amido groups.
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  • 18
    Electronic Resource
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    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 129 (1996), S. 697-713 
    ISSN: 0009-2940
    Keywords: Chiral tripodal ligands ; Tripod rhodium complexes ; Chiral diphosphanes ; Chiral phosphites ; Ring opening of epoxides ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Chiral Tripodal Ligands Bearing a Phosphite Donor Group: Synthesis and Coordination ChemistryThe mechanism of the reaction of epichlorohydrine (H-CH2Cl) (1) with lithium phosphides is analysed. A neighbouring-group mechanism has been found to be the essential driving force in this reaction. Monophosphanyl alcohols such as HOCH(CH2P(Ph)2)(CH2Cl) (2) and epoxides (Ph)2PCH2- (3) are characterized as intermediates. The mechanism leads to a rapid one-pot method for the synthesis of chiral racemic as well as enantiomerically pure bis(phosphanyl) alcohols HOCH(CH2PR2)(CH2PR2′) (4). The resulting bis(phosphanyl) alcohols 4 react easily with X2PCl (X = Cl; Ph; or X2 = 1,2-ethanedioxy-2,2′-biphenyldiyldioxy-) to yield the mixed donor group tripodal ligands X2POCH(CH2PR2)(CH2PR′2) (5, 6) containing both phosphite, phosphinite or phosphorodichloridite and phosphane donor groups. The identity of these compounds were proved by 1H-, 31P- and 13C-NMR spectroscopy, mass spectra, microanalysis as well as X-ray analysis. The coordination capabilities of these novel ligands are demonstrated by the synthesis and characterization of a (cyclooctadiene)rhodium complex {[(5c)Rh(I)COD]PF6} (7) of the ligand 5c, exhibiting the typical hetero-bicyclooctane tripod metal cage of this type of tripod complexes.
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  • 19
    Electronic Resource
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    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 129 (1996), S. 733-739 
    ISSN: 0009-2940
    Keywords: Silyl triflates ; Oligosilanes ; Polysilylated hydrocarbons ; Organosilicon polymers ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The highly reactive silyl triflates R4-nSi(OSO2CF3)n are valuable materials in organosilicon chemistry. Numerous new triflate derivatives of mono-, oligo-, and polysilanes were prepared by stepwise substitution of trifluoromethylsulfonyl groups for phenyl groups or other leaving groups. Conversions of silyl triflates with nucleophiles proceed regioselectively and, in most cases, quantitatively at low temperatures with short reaction times. Therefore, silyl triflates are suitable reagents for the synthesis and functionalization of linear and cyclic oligosilanes. Novel polycarbosilanes, polysilylalkynes, and polysilylphenylenes, which show a regular alternating arrangement of silylene groups and organic units, were prepared from α,ω-bis[(trifluoromethylsulfonyloxy)silyl]-substituted compounds and dinucleophiles. Branched polysilanes and polysilynes were obtained by reductive coupling of polymeric silyl triflates with potassium-graphite.
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  • 20
    ISSN: 0009-2940
    Keywords: Alkynylation ; Palladium catalyzed coupling reactions ; Cyclobutadiene complexes ; Iron complexes ; Cobalt complexes ; Modular chemistry ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The synthesis of mono-, di-, tri- and tetraalkynylated tricarbonyl(cyclobutadiene)iron complexes is accomplished by a repetitive metalation/iodination/coupling sequence. Application of this sequence leads to the synthesis of oligomeric cyclobutadiene complexes with various topologies, inter alia to the synthesis of a perethynylated dimer 24. Alternatively a one-step coupling procedure (Stille-Farina) has been used to synthesize tetraalkynylated tricarbonyl(cyclobutadiene)-irons 26.
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  • 21
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    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 129 (1996), S. 823-828 
    ISSN: 0009-2940
    Keywords: Aminosilanes ; Lithium compounds ; 1,3-Diaza-2,4-disilacyclobutanes ; 1-Aza-2,4-disilacyclobutane ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Di-tert-butylmethylsilylamide reacts with n-BuLi to give the tetrameric lithium di-tert-butylmethylsilylamide 1. Reactions of lithium (di-tert-butylmethylsilyl)amide 1 with SiF4 give the mono- (2), bis- (3), tris- (4), and tetrakis- (5) -[(di-tert-butylmethylsilyl)amino]silanes. Lithiated 3 reacts with Me3SiCl to form (di-tert-butylmethylsilyl-trimethylsilyl)amino-(di-tert-butylmethylsilyl)amino-difluorosilane (6); the 1,3-diaza-2,4-disilacyclobutane 7 is obtained by LiF elimination. The lithium derivative of 6 (compound 8) crystallizes with formation of a (SiFNLi) four-membered ring system. The 19F-NMR spectrum proves that the Li-F bond fluctuates in solution. Reactions of 1 with (Me3Si)2C(SiF3)2 afford different products (9, 10) by controlling the reaction sequence. An excess of 1 reacts to give a four-membered CSi2N ring system, the 1-(di-tert-butylmethylsilyl)-2,4-bis-[(di-tert-butylmethylsilyl)-amino]-2,4-difluoro-3-bis(trimethylsilyl)-1-aza-2,4-disila-cyclobutane (9), disubstitution with formation of bis[(di-tert-butylmethylsilyl)aminodifluorosilyl]bis(trimethylsilyl)methane (10) occurs in a molar ratio of 2:1. The cyclodisilazane 11 is obtained from dilithiated 10 in an intramolecular interconversion reaction. The crystal structures of 1, 8, 9, and 11 are reported.
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  • 22
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    Berichte der deutschen chemischen Gesellschaft 129 (1996), S. 841-844 
    ISSN: 0009-2940
    Keywords: Methane, methoxybis[tris(trimethylsilyl)silyl- ; Tris(trimethylsilyl)silyllithium ; Dichloromethyl methyl ether ; Polysilanes ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Methoxy-bis[tris(trimethylsilyl)silyl]methane (4), the first compound bearing two hypersilyl groups at a carbon atom, was synthesized by the reaction of tris(trimethylsilyl)silyllithium with dichloromethyl methyl ether. As a byproduct of the reaction, 1,2-dimethoxy-1,2-bis[tris(trimethylsilyl)silyl]-ethane (5) could be identified. Possible pathways leading to 4 and 5 are discussed. The structure of 4, elucidated by an X-ray crystal structure analysis, is characterized by tremendous distortions of the molecular skeleton due to the spatial demand of the two extended hemispherical (Me3Si)3Si groups. For example, the central Si-C-Si angle is widened to 132.7°, the trimethylsilyl groups of the two hypersilyl substituents are pressed together to give an average Si-Si-Si angle of 105.6°, and the methoxy carbon atom and the nearest neighboring trimethylsilyl carbon atom approach to a distance of 3.25 Å, i.e. approx. 19% less than the sum of the van der Waals radii of two methyl groups.
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  • 23
    ISSN: 0009-2940
    Keywords: Bis(arene)metal complexes ; Borane, dimesitylphenyl- ; Borane, diisopropylphenyl- ; Cyclic voltammetry ; EPR spectroscopy ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Metal π Complexes of Benzene Derivatives, 50. - Arylboranes as Sandwich Ligands: Preparation of [(iPrO)2B(η6-Ph)]2M and [Mes2B(η6-Ph)]2M (M = V, Cr). Redox Properties and EPR Study of M(d5) Neutral Complexes and Boron-Centered Radical AnionsBis(η6-arene)metal complexes bearing peripheral boryl substituents have been prepared by means of metal-atom ligand-vapor cocondensation leading to [(iPrO)2B-η6-C6H5]2Cr (7) and [(iPrO)2B-η6-C6H5]2V (8) as well as by lithiation and subsequent reaction with Mes2BF with formation of [Mes2B-η6-C6H5]2Cr (11) and [Mes2B-η6-C6H5]2V (12). According to the NMR spectra, rotation about the η-C-BR2 bonds in 7 and 11 is free at 25°C, restrictions setting in at -85°C. The neutral radicals 8• and 12• have been studied by EPR spectroscopy: despite of the profound difference in the electron-accepting properties of the groups (iPrO)2B- and Mes2B, the hyperfine coupling constants a(51V) differ by 5% only; the extent of perturbation of the electronic structure manifests itself more clearly in the g tensor, which is tetragonal for 8 but orthorhombic for 12, the degeneracy of the LUMO's e1g being raised in the latter. Cyclovoltammetry on 11 exhibits reversible oxidation as well as reduction processes. Reduction which, according to EPR, is ligand-centered, occurs in two steps which are separated by the redox splitting ΔE1/2 = 570 mV. This value, which is a measure of electronic communication between the two Mes2B groups, lies between those of 1,4-bis(dimesitylboryl)benzene (δE1/2 = 690 mV) and 4,4′-bis(dimesitylboryl)biphenyl (ΔE1/2 = 270 mV). The EPR spectrum of the radical anion 11-• reveals hyperfine coupling to one boron nucleus of a magnitude very similar to that of the free ligand radical anion Mes2BC6H5-•. Therefore, reduction of 11 is ligand-centered, and an intramolecular electron exchange between the boron centers is slow on the EPR time scale. As inferred from the observation of the hyperfine interactions a(53Cr) and a(1H), oxidation of 11 is metal-centered; relative to parent bis(η6-benzene)chromium (9), the two Mes2B groups cause an anodic shift of 290 mV for the couple 11+/0. The radical cations 11+• are prone to protodeborylation, in this aspect resembling the respective silyl derivatives.
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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
    ISSN: 0009-2940
    Keywords: ansa-Zirconocenes ; ansa-Titanocenes ; Alkyne complexes ; Pyridine ligands ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The reduction of the complex [(η5-C5H4)-ansa-(η5-C5H4)]TiCl2 with magnesium in the presence of Me3SiC2-SiMe3 in THF at room temperature gives the ansa-titanocone alkyne complex [(η5-C5H4)-ansa-(η5-C5H4)]Ti(η2-Me3SiC2-SiMe3) (ansa = Me2Si-O-SiMe2, 1). The similar pyridine-stabilized zirconium complexes could be obtained by analogous reactions and addition of pyridine: [(η5-C5H4)-ansa-(η5-C5H4)]Zr(L)(η2-Me3SiC2SiMe3) (ansa = Me2Si-O-SiMe2, L = pyridine: 2; ansa = SiMe2, L = pyridine: 3). All complexes were characterized by spectroscopic methods. An X-ray structure determination of complex 3 was conducted, and the data were compared to those of the complexes rac-(EB-HI)Zr(L)(η2-Me3SiC2SiMe3) [L = (S)-(-)-nicotine: 6, EBHI = ethylenebis(tetrahydroindenyl)] and Cp2Zr(py)(Me3SiC2-SiMe3).
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  • 29
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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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  • 30
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    Berichte der deutschen chemischen Gesellschaft 129 (1996), S. 997-1001 
    ISSN: 0009-2940
    Keywords: Ionic ozonides ; Ammonium ion, bisquaternary ; C-H…O hydrogen bonds ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The bisquaternary ammonium ozonides Me3N+(CH2)n +NMe3(O3-)2 with n = 3, 4, 6 (1, 2, 3), Me3N+(CH2)3+NMe3(O3-)2 · 3 NH3 (1a), Me3N+(p-Ph)+NMe3(O3-)2 (4) and Me3N+(p-Ph)+NMe3(O3-)2 · NH3 (4a) were obtained in quantitative yields by cation exchange starting from CsO3. The compounds 1a and 3 have been studied by single crystal X-ray analysis. The influence of C-H…O and N-H…O hydrogen bonds on the bond length and the bond angle of the ozonide anion is discussed; earlier results are included. The difference between the two bond lengths within the O3- ion [137.4(3) pm and 129.5(3) pm] in 1a is unexpectedly large. Thermal stabilities determined by DTA/TG methods range from 24-83°C.
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  • 31
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    Berichte der deutschen chemischen Gesellschaft 129 (1996), S. 1025-1028 
    ISSN: 0009-2940
    Keywords: Zinc hydroxide complexes ; Pyrazolylborate ligand ; Hydrolysis of esters and amides ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The molecular zinc hydroxide complex TpCum,MeZn—OH [1, TpCum,Me = tris(3-cumenyl-5-methylpyrazolyl)hydroborate] is a powerful nucleophile. It effects stoichiometric hydrolysis of activated esters RCO—OX and amides RCO—NHX in nonaqueous media. The cleavage products are TpCum,MeZn—OCOR and HOX or H2NX, resp. Two of them (TpCum,MeZn—OCO—CH2-CH2OH resulting from propiolactone and TpCum,MeZnOCO—CF3 resulting from trifluoroacetamide) were characterized by crystal structure determinations.
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  • 32
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    Berichte der deutschen chemischen Gesellschaft 129 (1996), S. 1041-1047 
    ISSN: 0009-2940
    Keywords: Biomimetic catalysis ; Oxygen activation ; Schiff base complexes ; Complexes of Mn, Fe, and Co ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The metal complexes (E,E)-[{diethyl 2,2′-[1,2-phenylenebis(iminomethylidyne)]bis[3-oxobutanoato]}(2-)-N,N′,O3,O3′]manganese (Mn1a), [3,3′]-[1,2-phenylenebis(iminomethylidyne)bis(2,4-pentanedionato)(2-)-N,N′,O2,O2′]manganese (Mn1b), and (Z,Z)-[diethyl 3,3′-(1,2-phenylenediimino)bis(2-cyano-2-propenoato)](2-)-N3,N3′,O1,O1′]manganese (Mn1c) were sythesised and the oxygenation of these complexes was investigated by gas volumetry. All complexes except Mn1c are able to take up oxygen but with different magnitudes. The catalytic activity of the Mn, Co, and Fe complexes of the ligands 1a and 1c and (E,E)-[{diethyl 2,2′-[1,2-ethylenebis(iminomethylidyne)]bis[3-oxobutanoato]} (2-)N,N′,O3,O3′] iron (Fe1d) and [diethyl (all-E)-5,14-dihydro-6,17-dimethyldibenzo[b,i][1,4,8,11]tetraazacyclotetradecine-7,16-dicarboxylato)(2-)-N5,N9,N14,N18]iron (Fe2a) has been compared with respect to the oxidation of hydroquinone by molecular oxygen. The results are interpreted with the aid of electrochemical properties, Lewis acidities, and other relevant factors. However, no simple relationship between the catalytic activity and the other factors could be found.
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  • 33
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    Berichte der deutschen chemischen Gesellschaft 129 (1996), S. 1083-1086 
    ISSN: 0009-2940
    Keywords: Phospholes ; Diphospholes ; Phosphonio substitution ; Methylation ; Pyramidal and planar three-coordination ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: P-Methylation of the 3,5-bis(triphenylphosphonio)-1,2-diphospholide 1 leads to the dicationic diphosphole 3a. A crystal of its bis(triflate) was used for a structure analysis. It indicates that in contrast to the known phospholes the cyclic π6 system is preserved in 3a. The coordination geometry of the methylated phosphorous atom shows a flat pyramid with a sum of angles of 339°. Therefore, 3a represents a state that is intermediate between a phosphane and a bis(methylene)phosphorane, i.e. between PIII and Pv.
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  • 34
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    Berichte der deutschen chemischen Gesellschaft 129 (1996), S. 1099-1101 
    ISSN: 0009-2940
    Keywords: Diboranes ; Transition-metal boryl complexes ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Reaction of Na[(Cp)Fe(CO)2] and Na[(Cp)W(CO)3] with B2(NMe2)2Cl2 yields the first transition metal-substituted diboranes [Cl(Me2N)B-B(NMe2)M(Cp)(CO)n] [M(Cp)(CO)n = Fe(Cp)(CO)2, W(Cp)(CO)3] (1a, b). The compounds were characterized in solution by NMR methods and in the crystal by X-ray structural determination.
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  • 35
    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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  • 36
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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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  • 37
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    Berichte der deutschen chemischen Gesellschaft 129 (1996), S. 1211-1217 
    ISSN: 0009-2940
    Keywords: Silver ; Macrocycles ; Cryptands ; Fluorine ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The partially fluorinated cryptands FN2O4 and BenzoFN2O4, which are relatives of the [2.2.1]cryptand, were synthesized in good yields from 1,3-bis(bromomethyl)-2-fluorobenzene and diaza-18-crown-6 or benzodiaza-18-crown-6, respectively. These macrobicyclic ligands form very stable complexes with Ag(I) salts, and it was shown that close fluorinesilver interactions occur in solution as well as in the solid state. Numerous experimental evidence for this is available: NMR competition experiments show that Ag+ complexes of FN2O4 are significantly more stable than those of HN2O4 (the two ligands are identical except that one fluorine atom is replaced by one hydrogen atom in HN2O4); the 1JCF coupling constants of Ag+ · FN2O4 and Ag+ · BenzoFN2O4 are reduced by 10 Hz compared to those of the respective free ligands FN2O4 (1JCF=253 Hz) and BenzoFN2O4. (1JCF=252 Hz). The X-ray crystal structure of Ag+ · FN2O4 revelas short Ag+-F distances [271.4(3) pm]; coupling of the 107,109Ag+ and 19F nuclei is observed in the 19F-NMR spectra (J=24 Hz for Ag+ · FN2O4, J=25 Hz for Ag+ · BenzoFN2O4). The 1H-NMR spectrum of Ag+ ·FN2O4 is very complex and exhibits sixteen unique proton resonances, whose evaluation yielded coupling constants and NOEs, which show that the structure in solution is compatible with the results obtained by the X-ray crystal structure determination.
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  • 38
    ISSN: 0009-2940
    Keywords: Zirconocenes ; Titanocenes ; N-Methyl-ε-caprolactam ; β-Propiolactam ; ε-Caprolactam ; Ring-opening polymerization ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Depending on the nature of the metal and the ring size, lactams react with titanocene and zircocene complexes of bis-(trimethylsilyl)acetylene Cp2Ti(Me3SiC2SiMe3) and Cp2Zr-(L)(Me3SiC2SiMe3) (L = Py, THF) to yield different products. In the reaction of Cp2Zr(Py)(Me3SiC2SiMe3) with N-methyl-€-caprolactam a simple ligand exchange reaction occurs and the complex Cp2Zr(Me3SiC2SiMe3)[O=H2)5] (1) was isolated. With β-propiolactam the alkenyl-amido complex Cp2)(SiMe3)][-NH2] (2) was obtained, which indicates that an agostic metal-hydrogen interaction has taken place. The reaction of Cp2Ti(Me3-SiC2SiMe3) with €-caprolactam gives after elimination of the alkyne and molecular hydrogen the first early transition metal complex with a deprotonated coordinated €-caprolactam in a η2-amidate bonding fashion (3). The obtained complexes were characterized by NMR spectra (1, 2) and crystal structure analysis (1-3) and discussed as elemental steps in anionic ring-opening polymerization of lactams catalyzed by metallocene-alkyne complexes.
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  • 39
    ISSN: 0009-2940
    Keywords: Synthesis aryl complexes of gold(III) ; Mercury(II) as transmetallating agent ; X-ray crystal structure ; Ketonylgold(III) complex ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The formylarylmercury(II) complex [Hg{C6H(CHO)-6-(OMe)3-2,3,4}2] reacts with 4-butylaniline (1:2) to give [Hg{C6H(CH=NC6H4C4H9-4′)-6-(OMe) 3-2,3,4}2] (1) by a condensation reaction. This complex reacts with Me4-N[AuCl4] (1:1) to give [Hg{C6H(CH=NC6H4C4H9-4′)-6-(OMe) 3-2,3,4}Cl] (2) and the monoarylgold(III) compound cis-C6H4-nBu-4′)-6-(OMe)3-2,3,4}Cl2] (3). This complex reacts with PPh3 (1:1) to give the adduct cis-[Au{C6H(CH=NC6H4-n, Bu-4′)-6-(OMe)3-2,3,4}Cl2(PPh3)] (4) and with AgClO4 (1:1) in acetone to give the ketonyl complex cis-[C6H4-nBu-4′)-6- (OMe)3-2,3,4}-{CH2C(O)Me}Cl] (5). cis-Me4N[Au(C6H4NO2-2)2Cl 2] react with [Hg{C6H3(N=NC6H4OMe-4′)-2-(OMe)-5}Cl] and Me4NCl (1:1:1) to give cis-[C6H4OMe-4′)-2- (OMe)-5}(C6H4NO2-2)2] (6): Similarly, cis-Me4N-[Au(C6H4CF3-2)2 Cl2] (7), obtained by treating [Hg(C6H4CF3-2)2] with Me4N[AuCl4] and Me4NCl (1:1:1), reacts with [Hg(C6H4CH2NMe2-2)Cl] and Me4NCl (1:1:1) to give the triarylgold(III) complex cis-[Me2-2)(C6H4CF3-2)2] (8). This complex can also be obtained by treating cis-[Me2-2)Cl2] with [Hg(C6H4CF3-2)2] and Me4NCl (1:1:1). The crystal structure of 3 reveals the presence of two independent molecules, in one of which the butylphenyl group is disordered. The geometry at the gold atom is square planar; distortions may be attributed to the narrow bite angle and steric repulsion between a chloride ligand and the ortho-methoxy group. The greater trans influence of the aryl ligand causes a great difference in Au-Cl bond lengths.
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  • 40
    ISSN: 0009-2940
    Keywords: Hexachlororhodates ; 1,4-Diammoniobutane ion ; Diaquahydrogen ion ; Hydrogen bonding ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Bis(1,4-diammoniobutane) diaquahydrogen hexachlorohodate(III) dichloride, [H3N-(CH2)4 -NH3]2[H5O2][RhCl6]Cl2 (1), was synthesized by the reaction of rhodium(III) chloride with 1,4-diaminobutane dihydrochloride in concentrated hydrochloric acid. The red compound slowly decomposes at room temperature, but is stable for months and up to 106°C (DTA) under hydrogen chloride. Crystals of 1 were obtained by diffusion-controlled crystallization (space group P,1¯). The solid-state structure can be considered as a sequence of layers linked by hydrophobic interactions between the aliphatic chains of the 1,4-diammoniobutane ions. Within these layers the hydrophilic building blocks (hexachlororhodate and chloride anions, the diaquahydrogen cations and the ammonio groups of the diammoniobutane cations) are connected by a complex system of O—H-Cl and N—H-Cl hydrogen bonds. The H5O2+ ion has a crystallographically imposed Ci symmetry and shows the typical 1:1 disorder of the central hydrogen atom for a symmetrically strong [O-O 2.406(10) Å] doubleminimum potential O-H-O bond.
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  • 41
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    Berichte der deutschen chemischen Gesellschaft 129 (1996), S. 1345-1353 
    ISSN: 0009-2940
    Keywords: Ethylene complexes ; Molecular orbital calculations ; Transition metal complexes ; Metal-nitrogen bonds ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: We report approximate molecular orbital calculations on models of the ethylene complex W(NMes)2(PMe3)2(η2-C2H4) 1. The ethylene unit in 1 is oriented perpendicular to the equatorial plane - an unusual orientation for trigonal bipyramidal L4M-(η2-C2H4) complexes. In order to understand the bonding in 1, the tungsten fragment W(NR)2L2 is discussed in some detail and we compare the “high valent” ethylene complex 1 and the “low valent” olefin complex Fe(CO)4(η2-C2H4). An analysis of π-bonding shows that the metal nitrogen bond in the cis,-[M(NR)2] unit is less than a triple bond, and the d2-[M(NR)L2] fragment is more like a 16 than an 18 valence electron fragment. The nature of the occupied d-orbital explains the opening of the angle E-M-E in trigonal bipyramidal complexes d2-cis-M(E)2L3. Both C2v fragments d2-W(NR)2L2 and d8-Fe(CO)4 have characteristic frontier orbitals, qualitatively similar to the frontier orbitals of CH2. These orbitals guide the ethylene ligand into or out of the equatorial plane. The general analysis leads to the conclusion that dn (n 〉 O) “high valent” complex fragments are actually better back-bonding donors for π-acidic ligands. For 1, we detect also another mininum on the energy surface - the olefin ligand is now oriented parallel to the equatorial plane. This raises the fascinating possibilities of the existence of multiple conformational minima for some transition metal ethylene complexes.
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  • 42
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    Berichte der deutschen chemischen Gesellschaft 129 (1996), S. 1361-1368 
    ISSN: 0009-2940
    Keywords: Lewis acid-carbonyl complexes ; Chiral oxazolidinone-TiCl4 adduct ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Mesityl aldehyde binds TiCl4 leading to the first structurally characterized TiCl4-aldehyde adduct, cis-[(MesCHO)2TiCl4] (Mes = 2,4,6-Me3C6H2) (1), which contains a pseudooctahedral titanium and two aldehyde carbonyl groups in a cis arrangement. However, in the case of 1:1 TiCl4-acetone adduct [(Me2CO)TiCl3)2(μ-Cl)2] (3) the solid-state structure of this acid-base complex is that of a chloro-bridged dimer. Both kinds of structures were suggested for the products [{(PhCOMe)TiCl3}2(μ-Cl)2] (4) and [cis-(PhCOMe)2TiCl4] (5) formed by the reaction of TiCl4 with acetophenone in 1:1 and 1:2 molar ratio. Thioesters behave like acetone in that they give adducts 8 and 9 with TiCl4, where 9, [{(PhSC(Me)O)TiCl3}2(μ-Cl)2], exhibits a solid-state dimeric structure like 3. The bidentate bonding mode of the chiral propionyloxazolidone 12 with TiCl4 was revealed by an X-ray analysis of 13.
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  • 43
    ISSN: 0009-2940
    Keywords: Trifuoromethylselanyl ; Trifluoromethylsulfanyl ; Acetic acid ; Esters ; Halides ; Hexafluoroarsenate ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Reaction pathways for the synthesis of the (CF3E)3C moieties (E = Se, S) are described. [(CF3Se)3C+][AsF6-] was found to be a suitable synthon for the preparation of (CF3Se)3C derivatives. It can be prepared either from (CF3Se)3C derivatives. It can be prepared either from (CF3Se)4C or (CF3Se)3CF and AsF5 in liquid SO2. Direct access to (CF3Se)3CF was realized by the reaction of FCBr3 with Hg(SeCF3)2. Treatment of [(CF3Se)3C+][AsF6-] with potassium halides provided (CF3Se)3CX (X = F, Cl, Br). A different course took the reaction with KI, as CF3SeSeCF3 and (CF3Se)2C=C(SeCF3)2 were formed as main products. Minor amounts of (CF3Se)3CC(SeCF3)3 were formed which could be isolated and unambiguously characterized. Only two routes led to a threefold CF3S-substituted acetic acid ester (CF3S)3CC(O)OR [R = CH3, (CH3)3C]: Metatheses between (CF3S)2CBrC(O)OCH3 and Hg(SCF3)2 and metalation of (CF3S)2CHC(O)OR [R = CH3, (CH3)3C] with NaH followed by reaction with CF3SCl. Other precursors such as (CF3S)2CXC(O)OR′ [X = H, Br; R′ = Me3Si, (n-C4H9)3Sn] and (CF3S)2CBrC(O) Y (Y = Cl, Br) were synthesized but could not be converted to the corresponding (CF3S)3C derivatives. Attempts to hydrolyze (CF3S)3CC(O)OR to (CF3S)3CC(O)OH failed.
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  • 44
    ISSN: 0009-2940
    Keywords: (Arene)tricarbonylmetals ; Borane, trimesityl ; Cyclic voltammetry ; MLCT transitions ; EPR spectroscopy ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
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  • 45
    ISSN: 0009-2940
    Keywords: Gallium - Gallium bonds ; Carboxylato bridges ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Yellow tetrakis[bis(trimethylsilyl)methyl]digallane(4) 1 reacts with two equivalents of the carboxylic acids RCOOH (R = -C6H5, -p-BrC6H4, -3,5-Me2C6H3, -CMe3) to yield almost quantitatively colorless products in which two bis(trimethylsilyl)methyl groups are replaced by two carboxylato ligands. As shown by a crystal structure determination with the 4-bromo-phenyl derivative (3), the Ga—Ga bond is bridged by both carboxylato groups in a chelating manner. The Ga—Ga distance is shortened to 238.5(2) pm (1: 254.1(1) pm) and the coordination number of the Ga atoms increased to four.
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  • 46
    ISSN: 0009-2940
    Keywords: Arene complexes ; Chromium compounds ; Substituent effects ; Push-pull chromophores ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The tricarbonylchromium complexes chlorobenzene 1 reacts with terminal alkynes 2 through a palladium-copper-catalyzed coupling to give a variety of Cr(CO)3-complexed phenylethynyl arenes, heteroarenes and ferrocene 3 in good to excellent yield. Due to the electron-withdrawing nature of the Cr(CO)3 group these novel complexes can be regarded as organometallic push-pull chromophores. Analogously, the corresponding free ligands 4 (phenylethynyl arenes, heteroarenes and ferrocene) were synthesized by coupling iodobenzene and 2. The crystal structure analysis of the singly Cr(CO)3-complexed tolane 3e reveals a strong deviation from coplanarity of both phenyl rings by an angle of 50.9(2)° presumably due to crystal packing. Correlations are established between selected substituent parameters (σP, σI, σR, σP+ and Δπ) and the carbonyl carbon resonances in the 13C-NMR spectra for the complexes 3. The overall electronic substituent effect is transmitted to the carbonyl groups by both mesomeric and inductive mechanisms. The push-pull complexes 3 display relatively small negative solvochromicities of longest wavelength absorption band (MLCT band).
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  • 47
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    Berichte der deutschen chemischen Gesellschaft 129 (1996), S. 1463-1474 
    ISSN: 0009-2940
    Keywords: Structure determination ; Mass spectrometry ; Oxidation processes ; Ion-molecule reactions ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The structures and energetics of [Fe,C3,H6,O]+ isomers are probed by mass spectrometric means. The complexes Fe-(CH3COCH3)+, Fe(CH3CH2CHO)+, Fe(CH3OCH=CH2)+, Fe(CH2O)(C2H4)+, c-(FeOCH2CH2CH2)+, Fe(CH2=CH-CH2OH)+, and Fe(OH)(C3H5)+ can be distinguished by comparing their reactivity toward benzene and their collision-induced dissociation mass spectra, respectively. These findings are used to interpret the formation of [Fe,C3,H6,O]+ in oxidation reactions of hydrocarbons by the highly reactive FeO+ cation. For example, in the reactions of FeO+ with norbornane and pentanol Fe(OH)(C3H5)+ is produced, while the reaction of FeO+ with norbornane to yield [Fe,C3,H6,O]+ is one of the rare cases of initial C—C bond activation by a “bare” transition-metal oxide. The reaction of FeO+ with propene involves formation of metalla oxetanes as primary products. In general, “bare” FeO+ is not selective and allylic C—H bond activation of propene competes efficiently, thus pointing to a potentially rich chemistry.
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  • 48
    ISSN: 0009-2940
    Keywords: Steroids ; Chiral amino alcohols ; Copper(II) salicylideneimine complexes ; X-ray analysis ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The steroidal 16β-salicylideneimino-17β-hydroxy compound 1, synthesized from the corresponding 16β, 17β-amino alcohol, served as a new tridentate chiral ligand for Cu2+-complexation. The X-ray data for 1 and for two dimeric copper complexes 2 and 3 are presented and discussed. Using copper(II) acetate for complexation, dideprotonation of 1 is observed. The neutral complex 2 obtained is characterized by a central planar four-membered copper - oxygen ring. The cycloaliphatic 17β-oxygen anions are bridging atoms; the copper ions are tetracoordinated. Reaction of 1 with copper(II) perchlorate gave only monodeprotonation of the phenolic groups. These oxygen anions are now the bridging atoms; furthermore the two copper ions are bridged by a perchlorate anion. Thus the central four-membered ring is folded (22°), and the copper ions are hexacoordinated (binding of a molecule of water). The crystal lattices of 2 and 3 are also quite different.
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  • 49
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    Berichte der deutschen chemischen Gesellschaft 129 (1996), S. 1603-1615 
    ISSN: 0009-2940
    Keywords: Tripod rhodium(I) complexes ; Pentacoordinate rhodium COD complexes ; Phosphane complexes ; Phosphite complexes ; Hydrogenation ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Tripod Rhodium COD Complexes: Synthesis, Structure, Dynamics and CatalysisThe reaction of the tripod ligands R′C(CH2PR2)3 (1a-c) and X2POCH[CH2P(Ph)2]2 (2a-c) with [RhI(COD)Cl]2] is investigated. It yields tripod rhodium COD complexes [(1a-c)RhI(COD)]Y (3a-c) and [(2a-c)RhI(COD)]Y [4a-c; Y = B(Ph)4, PF6]. The tripod ligand is coordinated by all three donor groups in each case, irrespective of the different donor capabilities of the coordinating groups. The solid state structure of compounds 3a-c and 4a is determined by X-ray analysis. The observed coordination polyhedra delineate the variation from the idealized trigonal bipyramide to an idealized quadratic pyramide. In solution the analysis of the NMR spectra shows a rapid intramolecular interconversion according to a turnstile pseudo rotation. The complexes 3a and 4a are found to be catalysts for the hydrogenation of prochiral olefines.
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  • 50
    ISSN: 0009-2940
    Keywords: Imidazoles ; Carbenes ; Sulfur Compounds ; Fluorine Compounds ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Imidazole Derivatives, XIXPart XVIII: Ref.[1] .  -  Coordination or reduction? On the Reaction of 1,3-Diisopropyl-4,5-dimethylimidazol-2-ylidene with Sulfur Halides and Sulfur Oxygen Halides Herrn Professor Max Herberhold zum 60. Geburtstag gewidmet.The reaction of 1,3-diisopropyl-4,5-dimethylimidazol-2-ylidene (4, Im) with sulfur halides and sulfur oxygen halides may be described as a coordination (1) or reduction (2) process in respect to the sulfur centre. With SCl2 and SOCl2 the hypervalent sulfur compounds Im · SCl2 (5) and Im · S(O)Cl2 (13) are obtained. The SF2 adduct Im · SF2 (11) is formed on treatment of 5 with AgF. 13 is alkylated by methyl iodide to give the Im · S(Me)OCl2 cation (15). Surprisingly, reduction of the sulfur centre (2) occurs on treatment of 4 with SF4 to form the ImF+SF3- salt 18 containing the new SF3 anion. As expected, the same type of reaction occurs with the sulfuryl halides SO2ClF and SO2F2 to give the fluorosulfites ImCl+-SO2F- (21) and ImF+SO2F- (23). The X-ray structures of 5, 13 and 23 are reported.
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  • 51
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    Berichte der deutschen chemischen Gesellschaft 129 (1996), S. 1-3 
    ISSN: 0009-2940
    Keywords: Planar-tetracoordinate carbon atoms ; Metallocene cations methyl ; Metallocene complexes alkynyl group-4 ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The methylhafnocene cation 2a reacts with bispropynylzirco-nocene to give a single regioisomeric planar-tetracoordinate carbon compound (4a) that contains the hafnium atom singly-bonded and the zirconium center η2-coordinated to the bridging μ-(η1-C:η2-C,C-2-butyne) ligand. However, the reaction between the methylzirconocene cation 2b with bis(phenylacetylide)hafnocene (3b) gives the pure regioiso-mer 4b with an opposite relative arrangement of the two group 4 transition metals (the methyl is at the planar-tetra-coordinate carbon atom C2). Complex 4a was characterized by an X-ray crystal structure analysis.
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  • 52
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    Berichte der deutschen chemischen Gesellschaft 129 (1996), S. 21-24 
    ISSN: 0009-2940
    Keywords: Orthoamides ; Trisaminomethanes, tricyclic ; Guanidinium cation, alkylation ; Copper(II) complexes ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The orthoamides 2a, b (R = Ph and PhCH2) have been prepared by alkylation of the guanidinium salt 4+BPh4- with PhNa and PhCH2Na, respectively. The crystal structures of the two orthoamides have been determined by X-ray crystallography. Their reaction with CuCl2 gives 1:1 complexes. The crystal structure of the complex with 2a shows a square planar geometry around the copper atom with η2-2a and two chlorides and weak interactions two the third nitrogen atom and a C-H bond of 2a in the axial positions.
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  • 53
    ISSN: 0009-2940
    Keywords: Oxalic Amidines ; Lithium diamides ; Calculations, PM3 ; Single-electron transfer ; Tetraaminoethenes ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Reduction of the 1,4-diaza-1,3-butadiene substructure of hexasubstituted oxalic amidines with lithium metal yields the new lithium diamides 3. Subsequent reaction of 3 with various electrophiles gives the title substances 4, 5, and the acylated derivative 6, respectively. The first SET step in this reaction is the formation of monolithium radical anions 2, which were detected by EPR spectroscopy. The second electron transfer leads to the deeply colored dianions 3. - In the case of compound 3a [cis-3a · 3 Et2O], the X-ray crystal structure reveals the cisoid arrangement of the bidental ligand and three molecules of diethyl ether which are located in a 2:1 fashion in the first coordination sphere of the lithium cations. The NMR 2D-1H,6Li-HOESY investigations of 3a in [D10]diethyl ether/diethyl ether (8:1) show Li+ contacts to the hydrogen atoms of the ether molecules and to the ortho-hydrogen atoms of the aryl moieties. Results of semiempirical calculations (PM3) are throughout in acceptable agreement with the experimental data and explain the unusual coordination pattern of the lithium cations of compounds 3.
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  • 54
    ISSN: 0009-2940
    Keywords: Halide complexes of 1-Halogen-2-phenylacetylenes ; Acetylenes, 1-halogen-2-phenyl-, halide complexes of ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Complexes of Halide Ions with 1-Halogen-2-phenylacetylenes. Crystal Structures of PPh4[X(I - C≡C - Ph)4] with X = Cl, Br, I, of PPh4[Br(Br - C≡C - Ph)4], and of NMe4[F(I - C≡C - Ph)2]Herrn Prof. Dr. H. Brunner zum 60. Geburtstag gewidmet.The complexes PPh4[X(I - C≡C - Ph)4] with X = Cl (1), Br (2), I (3), PPh4[Br(Br - C≡C - Ph)4] (4), and NMe4[F(I - C≡C - Ph)2] (5) were prepared from the corresponding salts PPh4X and NMe4F, respectively, with the 1-halogen-2-phenylacetylenes X - C≡C - Ph (X = Br, I) in dichloromethane solutions. 1 - 5 form colourless crystals, which were characterized by vibrational spectroscopy. According to the crystal structure determinations the halide ions in 1 - 4 are coordinated by the halogen atoms of the 1-halogen-2-phenylacetylenes in a tetragonal-pyramidal fashion. The fluoride ion in 5 is only twofold coordinated with a bond angle I - F - I of 110.45°.
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  • 55
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    Berichte der deutschen chemischen Gesellschaft 129 (1996), S. 137-142 
    ISSN: 0009-2940
    Keywords: Rhenium complexes ; Thiourea ; Clusters ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The reactions of Re2(CO)9(NCMe) and Re3(CO)10-(CH3CN)2(μ-H)3 with S=C(NEt2)N(H)(p-tolyl) have yielded the new compounds Re2(CO)9[S=C(NEt2)N(H)(p-tolyl)] (1) and Re3(CO)10(μ-SC(NEt2)N(H)(p-tolyl)](μ-H)3 (2) in 89% and 98% yields, respectively. Compounds 1 and 2 were characterized by single-crystal X-ray diffraction analyses. Compound 1 contains an S-coordinated S = C(NEt2)N(H)(p-tolyl) ligand terminally coordinated in an equatorial coordination site on one of the rhenium atoms. Compound 2 contains the first example of an S-coordinated bridging thiourea grouping. When solutions of 1 were heated to 97°C, it was transformed to the new compound {Re(CO)3[μ-SC(N-p-tolyl)(NEt2)]}2 (3) plus Re2(CO)10. Compound 3 is a centro-symmetrical dimer of the unit Re(CO)3[SC(N-p-tolyl)(NEt2)] in which the sulfur atom bridges the two rhenium atoms. The tolyl-substituted nitrogen atoms are coordinated to the rhenium atoms to form two Re-S-C-N rings.
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  • 56
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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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  • 57
    ISSN: 0009-2940
    Keywords: Cerium(IV) bis(porphyrinates) ; Zirconium(IV) bis(porphyrinates) ; Porphyrin, 2,3,7,8,12,13,17,18-octaethyl-5-methyl- ; Geometrical isomerism ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The synthesis of bis(2,3,7,8,12,13,17,18-octaethyl-5-methyl-porphyrinato)cerium(IV) and -zirconium(IV) [M(oemep)2; M = Ce, Zr, respectively] is described. The complexes were characterized by UV/Vis and IR spectroscopy and cyclic volt-ammetry. 1H-NMR spectra of the new cerium and zirconium sandwich complexes show that they exist as a mixture of vicinal and transversal isomers due to the rigid square-antipri-smatic coordination geometry found in metal(IV) bis(porphy-rinates). From the temperature dependence of the 1H-NMR spectra the rotational rigidity of the double-decker system was deduced. In toluene, free rotation of the two porphyrin macrocycles with respect to each other does not occur up to 373 K.
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  • 58
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    Berichte der deutschen chemischen Gesellschaft 129 (1996), S. 981-990 
    ISSN: 0009-2940
    Keywords: Molecular recognition ; Second-sphere coordination ; Transition metals ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The design and synthesis of artifical receptors, able to recognize and bind transition metal complexes, is an area of growing interest in supramolecular chemistry. Macrocyclic hosts such as crown ethers, cyclodextrins, and cyclophanes have been employed to generate second-sphere adducts with numerous transition metal complexes as a result of nonconvalent bonding interactions, such as hydrogen bonding, π-π stacking, and hydrophobic interactions. The effect of second-sphere coordination on the chemical, electrochemical, and photochemical properties of the adducts, as well as on their geometries in solution and in the solid state, has been investigated; these investigations have demonstrated the potential of second-sphere coordination in modulating the behavior of transition metal complexes by designed external intervention.
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  • 59
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    Berichte der deutschen chemischen Gesellschaft 129 (1996), S. 1003-1005 
    ISSN: 0009-2940
    Keywords: Heterometallic alkoxides ; Barium alkoxides ; Yttrium alkoxides ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Reaction of a 1:2 mixture of Y[N(SiMe3)2]3 and Ba[N(SiMe3)2]2 with tBuOH (8 mol equivalents) in Et2O at 25°C yields YBa2(OtBu)7(tBuOH), which has a triangular structure with two μ3-OtBu and three μ2-OtBu ligands, one terminal OtBu on Y and on one Ba, and one terminal tBuOH on the second Ba. All metals are thus five-coordinate. The crystal structure is comprised of chains of triangles of triangles held together by hydrogen bonds from tBuOH of one YBa2 unit to the terminal OtBu on Ba of the next YBa2 unit. This serves as support for the idea that, in certain cases, the heterometallic alkoxide product from alcoholysis of a mixture of two metal complexes can faithfully duplicate the global solution metal stoichiometry.
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  • 60
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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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  • 61
    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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  • 62
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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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  • 63
    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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  • 64
    ISSN: 0009-2940
    Keywords: Nickel cluster ; Nickel complex ; Thioamide ; Thiosemicarbazone ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Monomeric nickel(II) thiosemicarbazone complexes are an attractive new class of homogeneous catalysts for the activation of silanes. However, their activity is limited by the formation of inactive oligo- and polymers. The pathway by which aggregation takes place was elucidated by the preparation and X-ray structural analysis of the first trimeric nickel(II) thiosemicarbazone complex. Aggregation was shown to proceed via Ni—O—Ni and Ni—S—Ni bridging, giving rise to both fourfold planar and pseudooctahedral coordination of the nickel ions.
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  • 65
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    Berichte der deutschen chemischen Gesellschaft 129 (1996), S. 1447-1451 
    ISSN: 0009-2940
    Keywords: Allenes ; Manganese complexes ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Two products, Mn2(CO)7(PMe2Ph)[μ-η2-η2-MeO2C(H)CCC-(H)CO2Me] (1) in 9% yield and Mn2(CO)6(PMe2Ph)[μ-η3-η1-MeO2CC(H)CC(H)CO2Me] (2) in 34% yield, were obtained from the reaction of Mn2(CO)8(PMe2Ph)(MeCN) with MeO2C(H)C=C=C(H)CO2Me. Compound 1 contains a bridging η2-η2-MeO2C(H)CCC(H)CO2Me allene ligand and compound 2 contains a bridging η3-η1-MeO2C(H)CCC(H)-CO2Me allene ligand in which the oxygen atom of one of the carbonyl groups is also coordinated. Compound 1 slowly converts to 2, which establishes that it is a precursor to 2. Compound 2 reacts with NEtH2 to give the mononuclear manganese complex fac-Mn(CO)3(PMe2Ph)[MeO2CCH2-C=C(H)CO2Me] (3) in 96% yield. Compound 3 contains a chelating 1,3-di(methoxycarbonyl)propenyl grouping formed by addition of a hydrogen atom to the allene and the loss of a manganese grouping. Compounds 1-3 were characterized by single crystal x-ray diffraction methods.
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  • 66
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    Berichte der deutschen chemischen Gesellschaft 129 (1996), S. 1483-1488 
    ISSN: 0009-2940
    Keywords: Chiral carbenes ; (Carbene)palladium complexes ; Axial chirality ; Nomenclature ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The reaction of three equiv. of a chiral imidazolium or triazolium perchlorate with one equiv. of Pd(OAc)2, an excess of NaI and a base leads to the corresponding chiral dicarbenediiodopalladium(II) complexes in chemical yields up to 98% and with the trans isomer as the major product (1, 2). If only one equiv. of the imidazolium or triazolium perchlorate is used, then dinuclear complexes with bridging iodine atoms are formed (3, 4, chemical yield 92 - 94%). The latter can add Lewis basic ligands, e.g. amines, phosphanes or other carbenes, to give mononuclear complexes with one carbene ligand coordinated to the PdI2 fragment (5, 6). Preliminary test experiments with these Pd(II) complexes as catalysts for an enantioselective Heck-type reaction have been carried out.
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  • 67
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    Berichte der deutschen chemischen Gesellschaft 129 (1996), S. 1489-1492 
    ISSN: 0009-2940
    Keywords: Low-temperature synthesis ; Reactive flux method ; Quaternary europium polysulfide ; Low-dimensional materials ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The new quaternary europium polysulfide KCuEu2S6 was obtained using the reactive flux method at an intermediate temperature of 380°C by reacting K2S3 with elemental Cu, EuS and an excess of sulfur. The Eu3+ ions exhibit a bicapped trigonal prismatic coordination and the Cu+ ions are in a tetrahedral environment. The crystal structure is characterized by anionic layers of interconnected Eu and Cu polyhedra with K+ ions residing between the anionic sheets [Cu-Eu2S6]nn - . The Cu+ ions occupy one half of the tetrahedral sites in an ordered fashion.
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  • 68
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    Berichte der deutschen chemischen Gesellschaft 129 (1996), S. 1531-1534 
    ISSN: 0009-2940
    Keywords: Hydro-closo-borates ; Selenocyanato derivatives ; 11B NMR ; 77Se NMR ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The hydro-closo-borates [BnHn]2- (n = 6, 10, 12) react with (SeCN)2 in organic media to yield derivatives with one SeCN group bound via Se to the Bn polyhedra. This was verified by single-crystal X-ray structural analysis of the isotypical (P1¯) tetraphenylphosphonium salts (PPh4)2[(SeCN)B6H5] (1), (PPh4)2[1-(SeCN)B10H9] (2) and (PPh4)2[(SeCN)B12H11] (3) The 11B-NMR spectra reveal the features of monosubstituted hydro-closo-borates. The 77Se-NMR resonances are observed in the downfield region between δ = -22.6 and -78.8 characteristic of Se-bonded SeCN groups.
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  • 69
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    Berichte der deutschen chemischen Gesellschaft 129 (1996), S. 1561-1564 
    ISSN: 0009-2940
    Keywords: Sorbic acid, lithium salt ; Polymerization, solid-state ; Conductivity, ionic ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The structure of lithium sorbate (C6H7LiO2) was determined by single-crystal X-ray diffraction. It may be divided into organic and inorganic layers. The ionic part of the structure consists of a two-dimensional network of corner- and edge-sharing lithium oxotetrahedra, a structural pattern already known from other lithium carboxylates. Irradiation of the substance with X-rays or its thermal treatment results in the formation of a polymer exhibiting ionic conductivity at higher temperatures. Due to the rather large distances between potentially reactive atoms the polymerization results in a structural breakdown. Nevertheless, during the solid-state polymerization preferred orientations of building units are partially preserved. The probable course of the polymerization and the structure of the resulting polymer are discussed.
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  • 70
    ISSN: 0009-2940
    Keywords: Phosphazenes ; (2-Pyridylmethylamino) groups ; Copper complex ; Cobalt complex ; Platinum complex ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The reaction of the (2-pyridylmethylamino)-substituted cyclotriphosphazene N3P3(OC6H5)5(NHCH2(C5H4N)-2) (1) with copper(II) nitrate, platinum(II) chloride, and cobalt(II) nitrate yields the stable complexes [Cu(NO3)2·(1)2] (1a), [PtCl2·(1)] (1b), [Co(NO3)2 · (1)] (1c). The X-ray crystallographic studies of these metal complexes revealed the different coordination behavior of the multifunctional ligand.
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  • 71
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    Berichte der deutschen chemischen Gesellschaft 129 (1996), S. 29-31 
    ISSN: 0009-2940
    Keywords: Rhodium(I) complexes with phenyl and vinyl ligands ; Carbonylrhodium(I) complexes ; Thiocarbonylrhodium(I) complexes ; Rhodium(I) complex with CS2 as ligand ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The phenyl- and vinylrhodium(I) complexes trans-[Rh(R)(CO)(PiPr3)2] (2, 3) were prepared from the chloro derivative 1 and Grignard reagents. The corresponding thiocar-bonyl compound trans-[Rh(CH=CH2)(CS)(PiPr3)2] (7) was obtained similarly from trans, -[RhCl(CS)(PiPr3)2] (6) and CH2=CHMgBr. The preparation of 6 occurred via trans- [RhCl(η2-S=C=S)(PiPr3)2] (5) as intermediate. The carbonyl complexes 2 and 3 are quite inert in the presence of CO and do not react by migratory insertion to give acylrhodium derivatives.
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  • 72
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    Berichte der deutschen chemischen Gesellschaft 129 (1996), S. 53-58 
    ISSN: 0009-2940
    Keywords: P8 ligand ; P12 ligand ; P5-P3, P5-P7 building blocks ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The thermal and/or photochemical reaction of [Cp‴Co(CO)2] (1), Cp‴ = 1,2,4-tBu3C5H2, with white phosphorus, P4, gives besides [(Cp‴Co)2 (P2)2] (2) the trinuclear complexes [(Cp‴Co)3P8] (3) and [(Cp‴Co)3P12] (4), the Pn ligands of which form P5-P3 and P5-P7 skeletons, structural motifs, which formally can be derived from Hittorf's phosphorus. The X-ray crystal structure analysis of 3 confirmed its P5-P3 framework.
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  • 73
    ISSN: 0009-2940
    Keywords: Electronic structure ; Cyclopropenes, 3,3-dimethyl- ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: He(I) PE spectra of a series of 3,3-dimethylcyclopropenes bearing Me3Si (1), Me3Ge (2), and Me3Sn (3) groups in the 1- and 2-positions, as well as the He(II) PE spectra of 1 and 3 were recorded. The changes in the lowest energy ionizations along the series are interpreted in terms of inductive and hy-perconjugative interactions. The new compounds were prepared by reaction of lithiated 3,3-dimethylcyclopropene with the corresponding trimethylmetal chlorides.
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  • 74
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    Berichte der deutschen chemischen Gesellschaft 129 (1996) 
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
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  • 75
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    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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  • 76
    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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  • 77
    ISSN: 0009-2940
    Keywords: Electrophilic aromatic substitution ; Electrophilic vinylic substitution ; Aromatic aldehydes ; α,β-Unsaturated aldehydes ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: A mild and effective method for the preparation of a variety of aromatic (7a-m), heteroaromatic (7n-r), and α,β-unsaturated aldehydes (8a-f) is described. The reaction of trialkylaryl- (2a-o), heteroaryl- (2p-t), and 1-alkenylstannanes (4a-f and 5a-f) with dichloromethyl methyl ether (1, DCME) in the presence of aluminium trichloride followed by hydrolysis provides the corresponding aldehydes. In the case of arylstannanes the ipso-isomers are generally formed; the p-alde-hydes occur as side products. The electrophilic substitution of 1-alkenylstannanes with 1 leads to α,β-unsaturated aldehydes in an ipso- and stereospecific manner. A comparison of the leaving abilities of the stannyl and silyl groups shows a lower or even zero reactivity of the silyl-substituted compounds 6a-c towards the electrophile 1. In the silylstannylal-kene 6c only the stannyl group reacts whereas the stannyl function remains unaffected in the product, aldehyde 11.
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  • 78
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    Berichte der deutschen chemischen Gesellschaft 129 (1996), S. 77-83 
    ISSN: 0009-2940
    Keywords: Dimethylgold halides, complexes of ; Bidentate phosphorus ligands ; Bidentate arsenic ligands ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Dimethylgold(III) chloride and bromide, (Me2AuX)2, react with bis(diphenylphosphanyl)methane (dppm, molar ratio 1:2) to give the P-monohapto complexes cis-Me2AuX(dppm) (1a, b) in quantitative yields. The products are readily oxidized by air to yield the P-hapto P′-monoxides 2a, b. Treatment of 1a, b with AgNO3 affords an ionic nitrate [Me2Au(dppm)]2 [NO3-]2 (1c), which contains a dinuclear cation. A mixed bromide/nitrate (from 1b and half the equivalent amount of AgNO3) is thermally unstable and undergoes elimination of ethane to give an ionic tetranuclear gold(I) complex [(dppm)4Au4Br2]2+ [NO3-]2 (3b). - Treatment of (Me2AuCl)2 with CH2(AsPh2)2 (dpam, molar ratio 1:2) gives cis-Me2-AuCl(dpam) (1d), the arsenic analog of 1a, which is not sensitive to oxygen. - The reaction of bis(diphenylphosphanyl)-amine (dppa) yields 1:1 P-monohapto adducts Me2. AuX(dppa), which are in equilibrium with ionic chelated systems Me2Au(dppa)+ X- (1e, f). Complex 1e is readily oxidized by air to the P-hapto P′-monoxide cis complex 2e. Treatment of 1e with AgNO3 gives the ionic nitrate Me2. Au(dppa)+ NO3- (1g). - All compounds were identified by standard analytical and spectroscopic techniques. The crystal structures of 2a, 3b, 1d, and 2e were determined by single-crystal X-ray diffraction studies.
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  • 79
    ISSN: 0009-2940
    Keywords: Phosphane iminato complexes ; Arsenic compounds ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Phosphane Iminato Complexes of Arsenic. Crystal Structures of [AsCl(NPMe3)]2Cl2, [AsCl(NPMe3)2SbCl4]SbCl6, and [AsCl(NPMe3)2SnCl4] · CH3CN[AsCl(NPMe3)]2Cl2 (1) was prepared by the reaction of arsenic trichloride with the silylated phosphane imine Me3-SiNPMe3 in acetonitrile solution. According to the crystal structure determination, 1 has an ionic structure with [AsCl(NPMe3)]22+ ions, in which the As atoms are linked by the μ2-N atoms of the NPMe3- groups. Compound 1 reacts with antimony pentachloride to give [AsCl(NP-Me3)2SbCl4]+SbCl6- (2), with tin tetrachloride to form [AsCl(NPMe3)2SnCl4] (3), which is isoelectronic to the cation of 2. In 2 and 3 AsCl(NPMe3)2 acts as a chelating agent forming and , respectively, four-membered ring structures.
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  • 80
    ISSN: 0009-2940
    Keywords: Oxidation of silanediyls ; Silanone ; Oligomerization of silanones ; Silanethione ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Reaction of hexakis[2-(dimethylaminomethyl)phenyl]cyclo-trisilane (1) with isocyanates results in the clean formation of cyclic di- or trisiloxanes 3 and 4a and the corresponding isonitrile. Single-crystal X-ray analysis of tetrakis[2-(dimethylaminomethyl)phenyl]cyclodisiloxane (4a) reveals each silicon center to interact with two amino groups forming Si⃛N distances, which differ significantly in length. Phenyl isothio-cyanate reacts with 1 with transfer of sulfur to yield penta-coordinated bis[2-(dimethylaminomethyl)phenyl]silanethione (11).
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  • 81
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    Berichte der deutschen chemischen Gesellschaft 129 (1996), S. 483-484 
    ISSN: 0009-2940
    Keywords: Aminals ; Nucleophilic aminomethylation ; Si,N-Heterocycles ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The aminal Me2NCH2NMe2 is doubly metalated by LitBu to give LiCH2N(Me)CH2N(Me)CH2Li, which reacts with chlorosilanes to afford the respective silylated species, including the six-membered heterocycle Me2SiCH2N(Me)CH2N(Me)-CH2 and the spiroheterocycle Si[CH2N(Me)CH2N(Me)CH2]2.
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  • 82
    ISSN: 0009-2940
    Keywords: Selenium dioxide, 1,2-ethyloboration ; Selenium diimide, 1,2-ethyloboration ; Seleninic acid, ethane- ; Transborylation, OBEt2, O-9-BBN ; Ethene, elimination ; Amino(diethyl)boranes ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Both selenium dioxide (1) and selenium bis(tert-butylimide) (2) react with triethylborane (A) by 1,2-ethyloboration. In the case of 1, ethane, ethene, diethylselane (4a), tetraethyldiboroxane (Et2B)2O (B), triethylboroxine (EtBO)3 (D) and a cyclic compound [-Et2BOSe(Et)O-]2 (52) are formed after heating to 65°C. Compound 52 is also formed when 1 reacts with B. Treatment of selenous acid (3) with A or, preferentially for synthetic purposes, with B provides further routes to 52. The reaction of the diimide 2 with A starts already below -50°C: a cyclic ethaneselenic acid derivative 6, Et2BN(tBu)-Se(Et)NtBu, is formed, and 6 starts to decompose at -50°C by elimination of ethene to give finally (tert-butylamino)diethylborane (8), bis(diethylboryl)-tert-butylamine (9), and Et2Se (4a). Transborylation of 52 with (9-BBN)2O (C) affords [-(9-BBN)OSe(Et)O-]2 (102), which crystallizes in the monoclinic space group P21/n with the lattice constants (118 K) a = 667.1(1), b = 1282.5(1), c = 1289.1(1) pm and β = 93.06(1)°. All reactions were monitored by 11B- and 77Se-NMR spectroscopy. Furthermore, the reactions of 1 with A and B and the transborylations were studied by 17O-NMR spectroscopy using the 17O-enriched compounds 1(17O), B(17O), C(17O), and D(17O).
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  • 83
    ISSN: 0009-2940
    Keywords: Density-functional theory ; 31P-NMR chemical shift tensor ; Quasirelativistic pseudopotential ; Transition-metal phosphane complex ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The 31P chemical shift tensors of the transition-metal phosphane complexes M(CO)5PX3 (M = Cr, Mo, W; X = H, CH3, F, Cl) were studied using a combination of density functional theory and ab initio effective-core potentials. The calculated isotropic shifts agree well with experimental results both for the free ligands and for the complexes, with the largest deviations occuring for the tungsten complexes. A breakdown of the computed phosphorus shielding tensors into contributions from localized molecular orbitals (LMOs) indicates that the positive coordination shift of PH3 and P(CH3)3 is due to increased paramagnetic contributions from the phosphorus lone pair (P-M s̰ bonding) LMO to δ⊥. A similar increase of this contribution is found for PF3 and PCl3. However, for PCl3 complexes these terms are overcompensated by a reduction in the paramagnetic contributions from the P-Cl bonds and by shielding contributions from metal-centered orbitals. This results in a negative overall coordiantion shift. A partial cancellation is found with P(CH3)3 and with PF3. The changes in the 31P-shift tensors of the same phosphane ligands upon protonation are qualitatively and quantitatively very different from the coordination shifts and do not provide good models for the latter.
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  • 84
    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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  • 85
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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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  • 86
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    Berichte der deutschen chemischen Gesellschaft 129 (1996), S. 207-211 
    ISSN: 0009-2940
    Keywords: Zirconocene ; Titanocene ; Benzoxazoles ; Thiazoles ; Benzisoxazoles ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Zirconocene alkyne complexes Cp2Zr(L)(Me3SiC2R) (L = Py, THF; R = SiMe3 tBu) react with heterocyclic compounds like benzoxazole and related thiazoles to yield ring-expanded adducts (1-3) and (4, 5) by formal C-X (X = O, S) bond cleavage and coupling with the coordinated alkyne. In the case of benziso-xazole, the alkyne is not coupled but eliminated, and with ring-enlargement of the benzisoxazole a N-bridged dimer (6) is formed. The obtained complexes 1, 3, and 6 were characterized by NMR spectra and crystal structure analysis.
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  • 87
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    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 129 (1996), S. 227-232 
    ISSN: 0009-2940
    Keywords: β-Formyl esters ; Titanium enolates ; Lithium enolates ; Silyl enol ethers ; Chelate control ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The aldol-type additions of metal enolates 2-Met derived from pinacolone to the chiral β-formyl carboxylate 1a were optimized. The highest trans:cis ratio (86:14) of the products 3 was obtained when the trichlorotitanium enolate 2-TiCl3 was combined with 1a precomplexed with one equivalent of TiCl4. The lithium enolate 2-Li is rather unselective. The simple diastereoselectivity of prochiral enolates 4-Met was first examined with achiral β-formyl carboxylates 1b and 1c. Appropriate reagents made products with high anti or with high syn selectivity available when the unbranched aldehyde 1b was the electrophile. In contrast, the sterically more hindered aldehyde 1c provided syn products with all enolates 4-Met employed. Finally, chiral aldehyde 1a was combined with prochiral enolates 4-Met. Conditions could be found which furnished either the trans/anti or the trans/syn product 7 with good selectivity. The results are discussed and compared with reactions of related metal enolates with aldehydes capable of chelate formation.
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  • 88
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    Berichte der deutschen chemischen Gesellschaft 129 (1996), S. 243-245 
    ISSN: 0009-2940
    Keywords: Tripodal ligands ; Cobalt complexes ; Formate complexes ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Tripod-Cobalt Formate Complexes of Oxidation States +II and +IThe syntheses of the (tripod)cobalt formate complexes [(tri-pod)Co(O2CH)]n+ (1/1+; n = 0, 1; tripod = CH3C(CH2PPh2)3) are presented. The structures are established by X-ray analyses as well as the usual analytical techniques.
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  • 89
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    Berichte der deutschen chemischen Gesellschaft 129 (1996), S. I 
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
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  • 90
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    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 129 (1996), S. 275-277 
    ISSN: 0009-2940
    Keywords: Titanium complexes ; Amido-cyclopentadienyl ligand ; Tridentate ligand ; Lewis acidity ; Chelate effect ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Two new titanium complexes of the general type Ti(η5:η1-C5H4SiMe2NCH2CH2X)Cl2 (X = NMe2 OMe), containing a tridentate ligand, were prepared by reaction of Ti(η5-C5H4Si—Me2Cl)Cl3 with the lithium amide Li(NHCH2CH2X) (X = NMe2, OMe). The 1H—NMR chemical shifts for the protons of the ethylene link were found to vary considerably as a function of the temperature, indicating the presence of an equilibrium between the tri- and bidentate bonding mode of the ligand. A single-crystal X-ray structural analysis of Ti(η5:η1—C5H4SiMe2NCH2CH2OMe)Cl2 revealed that the methoxy function is not intramolecularly coordinated in the solid state.
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  • 91
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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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  • 92
    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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  • 93
    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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  • 94
    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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  • 95
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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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  • 96
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    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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  • 97
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    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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  • 98
    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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  • 99
    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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  • 100
    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)°].
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