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  • Inorganic Chemistry  (1,271)
  • 1995-1999  (567)
  • 1980-1984  (704)
  • 1955-1959
  • 1925-1929
  • 1995  (567)
  • 1981  (704)
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  • 1995-1999  (567)
  • 1980-1984  (704)
  • 1955-1959
  • 1925-1929
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  • 1
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 128 (1995) 
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
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  • 2
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 128 (1995), S. 29-34 
    ISSN: 0009-2940
    Keywords: Tripodal ligands ; Triamidostannates ; Metal-metal bonds ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: By in situ lithiation of the trifunctional amines H3CC(CH2NHSiMe3)3, PhC(CH2NHSiMe3)3, and HC{SiMe2NH(p-Tolyl)}3 and subsequent reaction with SnCl2 the corresponding triamidostannates were obtained. These were coupled with CpM(CO)2Cl (M = Fe, Ru) to yield the M - Sn-bonded heterobimetallics 9-14 of which H3CC(CH2NSiMe3)3SnFe(CO)2Cp (9) was characterized by a single-crystal X-ray structure analysis. Of the in situ-generated amidostannates only [HC{SiMe2N(p-Tolyl)}3Sn][Li(THF)3] (8) could be isolated as a uniform product and characterized analytically and spectroscopically.
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  • 3
    ISSN: 0009-2940
    Keywords: Selenium-nitrogen compounds ; Sulfur-nitrogen compounds ; Calculations, ab initio ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The structures of cationic species of the series [X2Y—N—YX2]+ (X = F, Cl; Y = S, Se) have been computed ab initio using all electron treatments for first-row elements and sulfur and quasi-relativistic pseudopotentials for Se and Cl. Splitvalence basis sets with polarization and diffuse functions were employed. The MP2 results for the (non-isostructural!) cations [Cl2Se—N—SeCl2]+ (1: Cs) and [F2S—N—SF2]+ (2: C2v) are in excellent agreement with the experimental (X-ray) observations. Both structures represent local minima. A deeper minimum for either of the cations is represented by another C2v isomer which for crystal lattice energy reasons is stable in the isolated state only. The geometries of the hitherto unknown species [Cl2S—N—SCl2]+ (3) and [F2Se—N—SeF2]+ (4) have been assessed by ab initio HF calculations. In analogy to 2, cations 3 and 4 are predicted to prefer C2v symmetry. Therefore, 1 exhibits unusual structural features. According to strictly localized natural bond orbital analysis (NBO), the central nitrogen atoms in 1 and 2 possess two lone pairs of electrons (LP: one sp hybrid and one p orbital). The relatively short Se—N and S—N bond distances in 1 (1.741-1.760 Å) and 2 (1.551 Å) can best be attributed to LP(N)→s̰*(Y—X) negative hyperconjugation (1: Y = Se, X = Cl; 2: Y = S, X = F).
    Additional Material: 8 Ill.
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  • 4
    ISSN: 0009-2940
    Keywords: Ruthenium(II) complexes, octahedral ; Phosphino esters as mono- and bidentate ligands ; Fluxional behaviour ; Carbene complexes ; Vinylidene complexes ; Allenylidene complexes ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Vinylidene Transition-Metal Complexes, XXXV[1].  -  The Supporting Role of Phosphino Ester Ligands for the Synthesis of Neutral Carbene, Vinylidene and Allenylidene Ruthenium(II) ComplexesThe reaction of [RuCl2(PPh3)3] (1) with the phosphino esters iPr2P(CH2)nCO2R (2-4) leads to complete (n = 1; R = CH3, C2H5) or partial (n = 2; R =CH3) displacement of the PPh3 ligands and formation of the octahedral ruthenium(II) complexes [RuCl2{k2(P,O)-iPr2PCH2CO2R}2] (5, 6) and [RuCl2(PPh3){k(P)-iPr2PCH2CH2CO2Me}{k2(P,O)-iPr2PCH2CH2CO2Me}] (7). Treatment of 5 with LiBr and LiI affords the dibromo- and diiodoruthenium derivatives 8 and 9. While compound 5 reacts with CO and SO2 by cleavage of one Ru - O bond to yield the 1:1 adducts [RuCl2(L){k(P)-iPr2PCH2CO2Me}{k2(P,O)-iPr2PCH2CO2Me}] (10, 11), the reaction of the dibromo derivative 8 with CO in solution gives the dicarbonyl complex [RuBr2(CO)2{k(P)-iPr2PCH2CO2Me}2](13). If CO is passed over 8 in the solid state, the corresponding monocarbonyl compound 14 is formed. The hydridoruthenium(II) complex 16, which is obtained from equimolar amounts of [RuHCl(CO)(PiPr3)2] (15) and 2, reacts with HC≡CMe by insertion to give the vinyl derivative [RuCl{E - CH=CHMe}(CO)(PiPr3){k2(P,O)-iPr2CH2CO2Me}] (17). Treatment of 5 with HC̊' (R' = H, Me, tBu, Ph) and of 6, 8, 9 with HC≡CPh affords upon photochemical activation the octahedral vinylidene complexes [RuX2-(=C=CHR){k(P)-iPr2PCH2CO2R}{k2(P,O)-iPr2PCH2CO2R}] (18-21 and 23-25) in good to excellent yield. At room temperature, these compounds (with the exception of 25) are highly fluxional in solution. From 31P-NMR measurements, the free energies of activation ΔG
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  • 5
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 128 (1995), S. 81-85 
    ISSN: 0009-2940
    Keywords: Aluminium-aluminium bond ; Insertion of trimethylsilyl azide ; Trimeric dialkylaluminium azide ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Reactions of R2Al—AlR2 (R = CH(SiMe3)2) with Trimethylsilyl Azide  -  Insertion into the Al—Al Bond and Formation of a Trimeric Dialkylaluminium AzideTetrakis[bis(trimethylsilyl)methyl]dialuminium(4) (1) reacts with trimethylsilyl azide under insertion of one nitrogen atom into the Al—Al bond. As shown by NMR spectra and crystal structure the product contains three and four coordinated Al atoms due to the coordination of the α-nitrogen atom of the azide group to one of the Al atoms. An electronically delocalized N3-system is formed with a N—N bond length of 132.0 pm and a bond order of 1.5 for both N—N bonds. With an excess of trimethylsilyl azide further reaction is observed only under mild irradiation conditions with an exchange of the azide group between Si and Al and formation of Me6Si2 and the dialkylaluminium azide 3, which is better synthesized by the reaction of Me3Si—N3 with Cl—Al[CH(SiMe3)2]2. The sterically highly shielded aluminium azide 3 is a trimer in the solid state showing a non-planar 12-membered Al3N9 heterocycle with short N—N bonds (114 pm).
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  • 6
    ISSN: 0009-2940
    Keywords: Poly(azolyl)borates, metal complexes of ; Bis(tetrazolyl)borate, metal complexes of ; Metal-nitrogen coordination ; Coordination polymers ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Dihydrobis(tetrazolyl)borate metal compounds of the composition [M(L)2{μ-H2B(CHN4)2}2]n for M = Mn, Fe, Co, Zn, Cd with L = H2O and for M = Cu with L = NH3 are obtained from metal salts and K[H2B(CHN4)2]. Single-crystal X-ray studies reveal the formation of two-dimensional rhombic grid sheets through the bridging action of the bis(tetrazolyl)borate ligands. Each metal atom is octahedrally coordinated with two trans L ligands and four H2B(CHN4)-2 nitrogen donors. Two additional, hydrogen-bonded water molecules occupy the rhombic openings in the compounds with M = Mn, Fe, Co, Zn, and Cd. The water of crystallization is held in place through hydrogen bonding from the water ligands and to the nitrogen atoms to give a substructure of parallel kinked water chains. Temperature-variable magnetic measurements show a Curie-Weiss behavior for the paramagnetic complexes with M = Mn, Fe, Co, and Cu.
    Additional Material: 8 Ill.
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  • 7
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 128 (1995), S. 365-371 
    ISSN: 0009-2940
    Keywords: Cumulenes ; Butadienes ; Vinylcyclopropane ; Vinylidenecyclopropane ; Bicyclopropyl, phosphanyl-substituted ; Cyclopropanation ; Phosphane ligands ; Phosphane chalcogenides ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Hydrophosphorylation of 1,4-bis(diphenylphosphanyl)butadiyne with diphenylphosphane leads to the butadiene (Ph2P)2C=CH—CH=C(PPh2)2 (1). Treatment of 1 with dimethylsulfonium methylide gives the vinylcyclopropane (Ph2P)2C=CH—CH(CH2)C(PPh2)2 (2). Compound 2 reacts with aqueous hydrogen peroxide, elemental sulfur, or selenium to afford the tetrachalcogenides (Ph2XP)2C=CH—CH(CH2)C(PXPh2)2 with X = O (3), X = S (4), X = Se (5), respectively. While the tetraphosphane 1 and the vinyl-cyclopropane compound 2 cannot be converted into a bis-(cyclopropyl) compound with an excess of Me2S=CH2, the tetrasulfide 4 readily affords a mixture of (1R,1′R)-/(1S,1′S)-and meso-2,2,2′,2′-tetrakis(diphenylthiophosphinyl)-1,1′-bicyclopropyl (6, 7) in good yield. Treatment of 1,1,4,4-tetrakis-(diphenylphosphanyl)butatriene with dimethylsulfonium methylide leads to the vinylidenecyclopropane (Ph2P)2C=C=C(CH2)C(PPh2)2 (8). Compound 8 is converted into its tetrasulfide (Ph2SP)2C=C=C(CH2)C(PSPh2)2 (9) by treatment with elemental sulfur. The crystal structures of 1, 2, 4, 7, and 8 have been determined by single-crystal X-ray diffraction.
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  • 8
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 128 (1995), S. 413-416 
    ISSN: 0009-2940
    Keywords: Ferriophosphanes ; Ferriophosphoranes ; Thioxophosphane ligand ; Decarbonylation reaction ; Sulfurization ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Mono- and Diferriophosphanes and -thioxophosphoranesHerrn Professor Dr. Ekkehard Lindner zum 60. Geburtstag gewidmet.The substitution of organic substituents in phosphanes or thioxophosphoranes by the 17-electron fragments CpFe-(CO)2 (—Fp) leads to isolobal ferriophosphanes or -thioxophosphoranes. The mono- and diferriophosphanes FpnPPh3-n [n = 1 (3), 2 (4)] are obtained by deprotonation of the mono- and diferriophosphonium salts [FpnPPh3-nH]X [n = 1 (1), 2 (2)] with DBU. They are oxidized by sulfur giving the mono- and diferriothioxophosphoranes FpnPPh3-n(S) [n = 1 (5), 2 (6)]. Sulfide 5 arises also from the reaction of CpFe(CO)2Cl and Ph2PH(S)/DBU. The one-sided decarbonylation reaction of 6 leads to FpFp′PPh(S) (7, Fp′ = CpFeCO). The Fp substituents (17 electrons) in 3-7 coordinate as one-electron donors to the PhnP- or PhnP(S) units (n = 1, 2). The bridging functions in 4 and 6 are hitherto unknown. The molecular structures of the complexes 5-7 were determined by X-ray structure analyses.
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  • 9
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 128 (1995), S. 435-436 
    ISSN: 0009-2940
    Keywords: Trifluoromethylthio group ; Carbenium ions ; Diphenylmethane ; Dyes ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Tris(trifluoromethylthio)carbenium hexafluoroarsenate (1) reacts with N,N-dimethylaniline and anisole to form the corresponding diphenylmethanes 2, 3 with the SCF3 group at the methine carbon atom. During the reaction of 1 with benzene, compounds such as C6H5C(SCF3)3 and C6H5SCF3 are formed along with benzophenone, a product of hydrolysis of the diphenylmethane compound.
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  • 10
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 128 (1995), S. 441-442 
    ISSN: 0009-2940
    Keywords: Diphosphane disulfides ; Metallophosphoranes ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The first transition metal derivative meso-[(η5-C5Me5)(CO)2FeP(H)(S)]2 (2) of the unknown diphosphane disulfide [PH2(S)]2 results from treatment of (η5-C5Me5)(CO)2FePH2 (1) with 1.5 equivalents of elemental sulfur. Compound 2 was characterized by means of spectroscopy (IR, 31P, 31P{1H}, 13C{1H}, 1H NMR) as well as X-ray diffraction analysis.
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  • 11
    ISSN: 0009-2940
    Keywords: Strontium bis(tetrahydridoborate)-2 tetrahydrofuran, chain polymer of ; Strontium bis(tetrahydridoborate)-bis(diglyme) ; Barium bis(tetrahydridoborate)-bis(diglyme) ; Strontium bis(tetrahydridoborate)-1,4,7,13,16-hexaoxacyclooctadecane ; Metal-hydrogen-boron bridges ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The strontium and barium tetrahydridoborate complexes M(BH4)2 · 2 diglyme and M(BH4)2 · 18-crown-6 (M = Sr, Ba) have been prepared from the solvates M(BH4)2 · 2 THF by ligand displacement. 11B-NMR and IR data reveal strongly polar bonding of the BH4 groups to the metal centers, and X-ray structural analyses of the diglyme and crown ether compounds show molecular units in which the BH4 group is in contact via three H atoms with the metal center. In contrast, M(BH4)2 · 2 THF compounds are chain polymers in the solid state, and each metal center is surrounded by 2 THF molecules in trans position and four BH4- groups each of which forms bridges with two metal centers. Estimations of the effective radius for the BH4 group indicate a high polarity for the M-BH4 interaction.
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  • 12
    ISSN: 0009-2940
    Keywords: Manganese ; Cycloheptadienyl ; Alkyne ; [5+2],homo[5+2] Cycloadditions ; Tricyclo[5.3.1.04,10]undeca-2,5-dien-11-yl ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Photochemical Reactions of Transition Metal Organyl Complexes with Olefins, 1312. Mitteilung: Lit. . - Photochemically Induced [5+2], homo[5+2] Cycloaddition of 3-Hexyne to Tricarbonyl(η 5-2,4-cycloheptadien-1-yl)manganeseTricarbonyl(η5-2,4-cycloheptadien-1-yl)manganese (1) reacts upon UV irradiation in hexane at 243 K with two equivalents of 3-hexyne (2) in successive [5+2],homo[5+2] cycloadditions to give tricarbonyl(η2:2:1-1,2,3,11-tetraethyltricyclo-[5.3.1.04,10]undeca-2,5-dien-11-yl)manganese (3). Its crystal and molecular structure was determined by an X-ray diffraction analysis, in solution it was studied also by IR and NMR spectroscopy.
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  • 13
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 128 (1995) 
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
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  • 14
    ISSN: 0009-2940
    Keywords: Anellated azaphospholes ; Hantzsch-type [3 + 2] cyclocondensation ; Chloromethyldichlorophosphane ; Regioselectivity ; 31P-, 1H-, 13C-NMR spectra ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The [3 + 2] cyclocondensation of 2-amino-1,3-thiazoline, 2-aminopyridines, 2- and 4-aminopyrimidines, 2-aminopyrazine, and 2-aminoquinoline with chloromethyldichlorophosphane in the presence of triethylamine yields regiospecifically 5,6-dihydrothiazolo[2,3-e][1,4,2]diazaphosphole (3), 1,4,2-diazaphospholo[4,5-α]pyridines (12), 1,4,2-diazaphospholo[4,5-α]pyrimidines (15), 1,4,2-diazaphospholo[4,5-e]pyrimidine (17), 1,4,2-diazaphospholo[4,5-α]pyrazine (19), and [1,4,2]diazaphospholo[4,5-α]quinoline (22), respectively. Using 2-amino-1,3-thiazole (4) and 2-aminobenzothiazoles 8, we obtained mixtures of the 1,5- and 4,5-anellated 1,4,2-diazaphospholes 5/6, 9a/10a and 9b/10b, while in the case of the methyl derivative 8c only the [1,4,2]diazaphospholo[5,4-b][1,3]benzothiazole 10c was formed. In the reaction of 2-aminothiazole and 2-aminopyrazine with Chloromethyldichlorophosphane the bis(diazaphospholo)-substituted chloromethylphosphanes 7 and 20 could be detected. The new anellated 1,4,2-diazaphospholes are colorless to pale yellow crystalline moisture-sensitive solids.
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  • 15
    ISSN: 0009-2940
    Keywords: Reductive silylation ; Aminochlorophosphanes ; Silylphosphanes ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The reaction of alkyl(diorganylamino)chlorophosphanes R(R2′N)PCl 1 (1a: R = tBu, R′ = Et, 1b: R = iPr, R′ = iPr; 1c: R = iPr, R′ = Ph) with hexachlorodisilane, afforded alkyl(diorganylamino)trichlorosilylphosphanes R(R2′N)PSiCl3 2 (2a: R = tBu, R′ = Et; 2b: R = iPr, R′ = iPr; 2c: R = iPr, R′ = Ph) and silicon tetrachloride. An intermediate formed in the reaction of 1b with hexachlorodisilane, the adduct iPr(iPr2N)(Cl)P-Si(Cl)3-SiCl3 (3b = 1b · Si2Cl6), was detected by 31P- and 29Si-NMR spectra that indicate pentacoordinated silicon bound to tetracoordinated phosphorus and tetracoordinated silicon. Trichlorosilylphosphanes 2 are also available from 1 under very mild conditions by reductive trichlorosilylation with trichlorosilane in the presence of triethylamine. Compounds 2 were identified analytically, by mass spectroscopy, multinuclear NMR, and an X-ray structure determination of 2c.
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  • 16
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    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 128 (1995), S. 641-643 
    ISSN: 0009-2940
    Keywords: Carbene ligands ; Tungsten complexes ; 2,2′-Bifuran ; Copper coupling reaction ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The 2-oxacyclic α,β-unsaturated carbene complex 1 reacts with an excess of dimethylamine to give the diphenylbifuran 2. The structure of 2 was established by independent synthesis from 2-phenylfuran (4) via regioselective lithiation and transmetalation to zinc and tin organometallics 6a-c and final oxidative copper coupling reactions.
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  • 17
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    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 128 (1995), S. 679-687 
    ISSN: 0009-2940
    Keywords: Stannole, diethylboryl-substituted ; Trimethyltin alkoxides ; 2-, 3-Stannolenes, organometallic-substituted ; NMR, coupling constants, 2J(Sn,Sn), sign determination ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Trimethyltin alkoxides (2) react stereoselectively with 3-diethylboryl-4-ethyl-1,1-dimethylstannole (1) via addition of the Me3Sn group to C(2) to the C(2) = C(3) bond and a 1,2 shift of an ethyl group from boron to C(3) to give the 2-stannolenes 3. The molecular structure of 3f' [R = (S)-2-Bu] was determined by single-crystal X-ray analysis, confirming the cis positions of the Et(RO)B and the Me3Sn group. These 2-stannolenes 3 undergo, upon heating to ca. 80°C, facile rearrangement by irreversible allylic migration of the Et(RO)B group to the 3-stannolenes 4 in which the cis positions of the boryl and the stannyl group are retained. All 2-stannolenes (in contrast to the 3-stannolenes) are readily deprotoborylated to give the 3-stannolene 5. The structures of 3, 4, and 5 follow conclusively from 1H-, 11B-, 13C-, and 119Sn-NMR spectra. The negative sign of the geminal coupling constants 2J(SnSn) was determined in the case of 3, 4, and 5 by 2D 119Sn/1H heteronuclear shift correlations.
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  • 18
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    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 128 (1995), S. 751-762 
    ISSN: 0009-2940
    Keywords: Trifluoroacyloxy-9-borabicyclo[3.3.1]nonane ; Pivaloyloxy-9-borabicyclo[3.3.1]nonane dimer ; Bis(9-borabicyclo[3.3.1]nonyl]oxalate ; Tetrakis(9-borabicyclo[3.3.1]nonyl)-dihydroxyoxalate ; Bis(9-borabicyclo[3.3.1]nonyl)-2,2-dimethylmalonate tetramer ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: 9-Borabicyclo[3.3.1]nonane (9-BBNH) reacts with monocarboxylic acids to afford 9-(acyloxy)-9-borabicyclo[3.3.1]nonanes which are dimers in the solid state as shown by X-ray crystal structures of the benzoate and pivalate. More complex reactions were observed by allowing 9-BBNH to react with dicarboxylic acids in THF or monoglyme. Thus, (9-BBN)2 oxalate 3 contains a fully delocalized oxalate unit with equal C-O and B-O bond lengths. Traces of water convert it into the tetrakis(9-BBN) oxalate 5. A rather unusual structure is veryfied by 9-BBN 2,2-dimethylmalonate 7 which according to its molecular structure is a tetramer featuring a 32-membered ring system. In contrast, reactions of oxalic acid with thexylborane leads to reduction of the acid and formation of a bicyclic dioxaborolo-dioxaborolane 10. Several intermediates were detected by 11B-NMR spectroscopy as well as in reactions of BH3 · THF or BH3 · SMe2 with oxalic acid.  -  It follows from the present study that (acyloxy)boranes derived from dicarboxylic acids are strong Lewis acids with an unexpected variety of structural features.
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  • 19
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    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 128 (1995), S. 741-742 
    ISSN: 0009-2940
    Keywords: Selenenyl halides ; Nucleophilic substitution ; Complex intermediate ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The T-shaped selenenyl halide (1), which may be regarded as a model substance for the transition state in nucleophilic displacement at divalent chalcogen atoms, has been isolated and subjected to X-ray structure determination.
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  • 20
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    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 128 (1995), S. 779-785 
    ISSN: 0009-2940
    Keywords: Zinc complexes ; Drug ligands ; Captopril ; Isoniazid ; Nalidixic acid ; Mercaptopurine ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Four drugs whose actions have a relation to the status of zinccontaining species in the human body were used as ligands in zinc complexes. Captopril (H2Cap) forms the compound [ZnCap] (1) presumed to be a coordination polymer with O and S coordination. Isoniazid, in the presence of zinc salts, is converted to 1,2-diisonicotinoyl hydrazide (H2Nih) which forms polymeric [Zn(Nih)NH3] (2) with trigonal-bipyramidal ZnO2N3 coordination. Nalidixic acid (HNal) and zinc perchlorate yield [Zn(HNal)2(H2O)2](ClO4)2 · 2 H2O (3) containing zinc in an octahedral ZnO6 environment. Mercaptopurine (H2Mer), in the presence of ammonia, forms [Zn(Mer)(NH3)2] . H2O (4) which is a coordination polymer containing tetrahedral ZnN4 units. The structures of [Zn(Nih)NH3], [Zn(HNal)2(H2O)2](ClO4)2 . 2 H2O, and [Zn(Mer)(NH3)2] . 2 H2O were determined diffractometrically.
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  • 21
    ISSN: 0009-2940
    Keywords: Phosphate-phosphonate rearrangement ; Carbanions, benzylic, configurational stability of ; Phosphonaes Lithium amides, homochiral ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Benzyl dialkyl phosphates are deprotonated enantioselectively by homochiral lithium amides of isopropyl(1-phenylethyl)amine or bis(1-phenylethyl)amine. The short-lived benzylic carbanions formed are virtually configurationally stable relative to the rearrangement to optically active phenyl-hydroxymethylphosphonates. The enantiomeric excesses are up to 50%. The pro-(S) hydrogen is removed by amides having (S) configuration. Homochiral diethyl (S)-phenyl[D1]-methyl phosphate [(S)-16c] is deprotonated by both LDA and n-BuLi with a high primary kinetic isotope effect (kH/D ≍ 50) and isomerizes to the corresponding α-hydroxy phosphonate with an enantiomeric excess of up to 85%.
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  • 22
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    Berichte der deutschen chemischen Gesellschaft 128 (1995), S. 845-850 
    ISSN: 0009-2940
    Keywords: Phenanthroline synthesis ; Tris(phenanthroline)iron(II) complexes ; Redox potential ; Cyclic voltammetry ; Electron transfer, outer-sphere ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The new 4,7-donor-substituted phenanthrolines 2a-h were synthesized and the corresponding tris(1,10-phenanthroline)iron(II) complexes 3a-h studied by cyclic voltammetry. In more detail three novel aza-crown ether-linked (phenanthroline)iron complexes were investigated, the redox potentials of which could be fine-tuned by the addition of group-Ia,IIa metal cations. All iron(II) complexes showed reversible waves at scan rates between 50 and 500 mV · s-1 and could be reversibly oxidized and reduced by chemical means.
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  • 23
    ISSN: 0009-2940
    Keywords: Bis(cyclopentadienyl)methane ; Heterobimetallic complexes ; Imido complexes ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The mononuclear rhodium complexes [(C5H5CH2C5H4)-Rh(CO)2] (1) and [(C5H5CH2C5H4)Rh(PhC≡CPh)(PiPr3)] (2) readily react with nBuLi or TlOEt to yield the corresponding lithium salts 3 and 4 or thallium salts 5 and 6. The reaction of these salts with [(C5H5)Nb(NtBu)Cl2] (7) leads to the formation of the heterodinuclear compounds [{CH2(C5H4)2}-{Rh(CO)2}{(C5H5)Nb(NtBu)Cl}] (8) and [{CH2(C5H4)2}-{Rh(PhC≡CPh)(PiPr3)}{(C5H5)Nb(NtBu)Cl}] (9), respectively. Treatment of 3-6 with [Mo(NtBu)2Cl2] (10) gives the heterodinuclear Rh/Mo complexes [{CH2(C5H4)2}{Rh(CO)2}-{Mo(NtBu)2Cl}] (11) and [{CH2(C5H4)2}{Rh(PhC≡CPh)-(PiPr3)}{Mo(NtBu)2Cl}] (12). The analogous reaction of [Mo(NMes)2Cl2(DME)] (13) with 3-6 yields the corresponding complexes [{CH2(C5H4)2}{Rh(CO)2}{Mo(NMes)2Cl}] (14) and [{CH2(C5H4)2}{Rh(PhC≡CPh)(PiPr3)}{Mo(NMes)2Cl}] (15). From the monometallated ligand [(C5H5CH2C5H4)M] (M = Li: 16; M = Tl: 17) and the imidometal compounds 7, 10 and 13, the mononuclear complexes [(C5H5CH2C5H4)(C5H5)Nb-(NtBu)Cl] (18) and [(C5H5CH2C5H4)Mo(NR)2Cl] (R = tBu: 19; R = Mes: 20) have been obtained.
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  • 24
    ISSN: 0009-2940
    Keywords: Fullerene ; Hydrofulleride ; Manganese complex ; Rhenium complex ; Iron complexes ; Ruthenium complex ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Addition of Hydrofulleride [C60H]- to Coordinated, Unsaturated Hydrocarbons: Binding of Fullerene to Metal Complexes through Hydrocarbon BridgesHerrn Professor Herbert Walter Roesky zum 60. Geburtstag gewidmet.Hydrofulleride [C60H]- is added to the hydrocarbon ligands of the cationic complexes [(OC)5Re(η2-C2H4)]+, [(OC)3Mn-(η6-C6H6)]+, [(OC)3M(η5-C6H7)]+ (M = Fe, Ru), [(OC)3Fe(η5-C7H9)]+, and [(η5-C5H5)Fe(η6-C5H4CH2)]+.
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  • 25
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    Berichte der deutschen chemischen Gesellschaft 128 (1995), S. 1083-1088 
    ISSN: 0009-2940
    Keywords: Silenes ; Silene dimerization ; 1,2-Disilacyclobutanes ; 1,3-Disilacyclobutanes ; 2,3-Disilanaphthalene, tetrahydro- ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Mesityl[tris(trimethylsilyl)silyl]methanol (1) reacts with strong bases with elimination of trimethylsilanolate according to a Peterson-type mechanism, the outcome of the reaction being dependent on solvent, temperature, and nature of the organometallic base applied. Thus, 1 was converted by treatment with MeLi in ether at -78°C to (E)-1,2,3,8a-tetra -hydro-1-mesityl-5,7,8a-trimethyl-2,2,3,3-tetrakis (trimethylsi-lyl)-2,3-disilanaphthalene (3), formally a [2 + 4] cyclodimer of the transient silene (Me3Si)2Si=CHMes (2). The reaction of 1 with PhMgBr in THF after some days resulted in the formation of (Z)-3,4-dimesityl-1,1,2,2-tetrakis(trimethylsilyl) -1,2-disilacyclobutane (6) as the main product besides small quantities of 3, the polysilane (Me3SiSi(SiMe3)2CH2Mes (10), and the alkoxysilane (Me3Si)3SiCH(Mes)OSi(Si-Me3)2CH2Mes (7). Compound 6, the formal [2 + 2] cycloadduct of 2, can also be obtained by thermal treatment of 3 and is considered to be the thermodynamically more stable silene dimer whereas 3 is the kinetically preferred product. At high LiBr concentrations in the reaction mixture 1 was converted by PhMgBr in THF to (E)-2,4-dimesityl-1,1,3,3-tetrakis(tri- methylsilyl)-1,3-disilacyclobutane (13) besides 6 and [bis(tri-methylsilyl)silyl]mesityl(trimethylsiloxy)methane (11). The unforeseen formation of 13 is discussed as proceeding via the silene-lithium bromide adduct (Me3Si)2Si(Br)CH(Li)Mes (12). In the absence of LiBr 1 was converted by MeLi in THF at -78°C to 11 and the trisilane (Me3Si)2Si(Me)CH2Mes (4b). Probable pathways of the formation of all new compounds are discussed. For 6 and 13 the results of the X-ray structural analyses are given.
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  • 26
    ISSN: 0009-2940
    Keywords: 1,7-Dimethylocta-2,6-diene-1,8-diyl ; Ruthenium complexes ; α-Amino carboxylates ; α-Amino acid esters ; Peptide esters ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Metal Complexes Containing Biologically Important Ligands, LXXXLXXIX. Mitteilung: Lit. .  -  (η3:η3-C10H16)Ru(IV) Complexes with α-Amino Carboxylates, α-Amino Acid Esters, and Peptide Esters as LigandsReactions of the chloro-bridged bis(allyl) complex [(η3:η3-C10H16)Ru(Cl)(μ-Cl)]2 with α-amino carboxylates and α-amino acid esters afford the complexes (η3:η3-C10H16)(Cl)RuNH2CHRCO2 (2) and (η3:η3-C10H16)(Cl)2-RuNH2CHRCO2R′ (3). Abstraction of chloride from 3 by Ag+ gives the N,O-chelates [(η3:η3-C10H16)(Cl)RuNH2CHRCO2R′]+BF4 (4). Cysteine methyl ester forms the N,S-chelate complex (η3:η3-C10H16)(Cl)RuNH2CH(CO2CH3)CH2S (5), and with histidine methyl ester a dinuclear complex 6 with N,N-histidine bridge is obtained. Compound 3d with L-PheOEt as ligand was characterized by X-ray diffraction.
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  • 27
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    Berichte der deutschen chemischen Gesellschaft 128 (1995), S. 1135-1136 
    ISSN: 0009-2940
    Keywords: Hemilabile ligands ; Cyclopentadienyl ligands, functionalised ; Iron compounds ; Halfsandwich complex ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Reaction of iron(II) chloride with one equivalent of [MeO-(CH2CH2O)3(CH2)3C5Me4]Li in THF yields the title halfsand-wich complex 1, which is stable in solution up to room temperature. Compound 1 reacts with C5H5Li and CO to give [MeO(CH2CH2O)3(CH2)3C5Me4]Fe(C5H5) (2) and [MeO-(CH2CH2O)3(CH2)3C5Me4]Fe(CO)2CI (3), respectively, in high yields.
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  • 28
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    Berichte der deutschen chemischen Gesellschaft 128 (1995), S. 1145-1148 
    ISSN: 0009-2940
    Keywords: P2, As2, P2S2, and P2Se2 ligands ; Iron complexes ; Triangulated dodecahedra ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The thermolysis of [CpFe(CO)2]2 (1) and P4 or As4 affords the iron clusters [Cp4Fe4(E2)2], E = As (2a), P (2b), the Fe4E4 skeleton of which consists of a triangulated dodecahedron. S8 and gray Se oxidize the P2 ligands of 2b with formation of [Cp4Fe4(P2X2)2], X = S (3a), Se (3b), complexes with the hitherto unknown P2X2 ligands, 2a, b and 3a, b have been characterized by X-ray crystallography.
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  • 29
    ISSN: 0009-2940
    Keywords: Synthesis, stereoselective ; Catalysis ; Tetrahydrofurans ; Dialkylzinc reagents ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: 1,4-Diol derivatives 4a-i were synthesized stereoselectively by either reagent- or catalyst-controlled routes using the addition of functionalized diorganozinc reagents to aldehydes. The stereoselectivities along the reagent-controlled synthetic path were in the range between 80:20 and 95:5. The stereoselectivities along the catalyst route exceeded 95:5. The 1,4-diol derivatives 4 thus obtained were transformed into enantiomerically pure cis- and trans-2,5-disubstituted tetrahydrofurans (16-20) by means of an intramolecular Williamson reaction.
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  • 30
    ISSN: 0009-2940
    Keywords: Hydrazines ; N,N'-bis(diphenylboryl)-N,N'-dimethyl- ; N,N'-bis(diphenylboryl)-N',N'-dimethyl- ; N,N'-bis(dimethylphenylsilyl)- ; N,N'-bis(chloromesitylboryl)-N'-phenyl-N'-(trimethylsilyl)- ; 1,2,4,5,3,6-Tetrazadiborinane, 1,2,4,5-tetrakis(tert-butyldimethylsilyl)-3,6-difluoro- ; Triazadiborolidine, dihydro-, derivative ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The diboration of the diazene PhN = NSiMe3 (15) by diborane(4) derivatives provides a new synthetic route to N,N'-diborylated hydrazines. The product formed depends on the type of the diborane(4) compound. Thus, addition of dimesityldiboron dichloride to 15 in a 1:1 ratio afforded (mesCIB)PhN-N(SiMe3)(BClmes) (16) while bis(dimethyl-amino)diboron dichloride was found to react in a 1:2 ratio to give a triazadiborolidine derivative 17. In addition, it was demonstrated that in the solid state Me2N-N(BPh2)2 (8) is a derivative of a three-membered dihydroazadiboriridine C while its isomer, (Ph2B)MeN-NMe(BPh2) (7), forms no BN coordinative bond. The new 3,6-difluoro-1,2,4,5-tetraza-3,6-diborine 13 shows a twist conformation. The molecular structures of all these compounds were determined by X-ray crystal structure analysis, and the influence of the B substituent on the conformation is discussed.
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  • 31
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    Berichte der deutschen chemischen Gesellschaft 128 (1995), S. 1061-1068 
    ISSN: 0009-2940
    Keywords: N-Isocyanides ; N-Isocyanodialkylamine complexes ; Carbene complexes ; Imaging-Plate data collection ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The N-isocyanodialkylamine metal complexes [M(CO)5CN-NR2] (M = Cr, W), trans-[MI2(CNNR2)2] (M = Pd, Pt), trans-[Pt(Cl)(CNNR2)(PPh3)2]BF4, and cis-[PtCl2(CNNR2)(PPh3)] [R = Et, iPr; 2 R = -{CHMe(CH2)3CHMe}-] react with primary amines to give the amino(hydrazino)carbene metal complexes [M(CO)5(C(NHR′)NHNR2}] (R′ = Me, nPr, Cy) (1-9), trans-[PtI2{C(NHMe)NHNR2}2] (10-12) and trans, and the amine adducts cis-[PtCl2{C(NHMe)NHNC(H)(Me) (CH2)3CHMe}(PPh3)] H2NMe (14), and trans-[PdI2{C (NHMe)NHNC(H)(Me)(CH2)3CHMe}2] 2 H2NMe (15). With secondary amines the amino(hydrazino)carbene metal complexes trans (18) and trans-[PtCl{C(NEt2)NHNEt2} (PPh3)2]BF4 (19) Were isolated. The complexes trans-[PtI2{C(NHCy)NHNiPr2}CNNiPr 2] (20) and trans-[PdI2 (NH2Cy){C(NHCy)NHNiPr2}] (21) were obtained by reaction of trans-[MI2(CNNiPr2)2] (M = Pd, Pt) with cyclohexylamine. The structures were assigned on the basis of IR, NMR- (1H, 13C, 31P), and mass spectroscopy as well as an X-ray structural analysis of 21.
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  • 32
    ISSN: 0009-2940
    Keywords: [2.2.2]Paracyclophanes ; Polyenes ; Silver complexes ; X-Ray structural analysis ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The preparation of the disilver(I) complexes 3 and 4, polyene metal complexes that are terminally substituted with [2.2.2]paracyclophanyl units, is described. NMR spectro-scopic studies on the disilver perchlorate complex 3b showed that (a) the sites of complexation are the cyclophane groups and (b) the olefinic spacers do not overly perturb the overall complexation properties of the individual [2.2.2]paracyclo-phanyl groups. The crystal structures of the disilver hexafluo-roantimonate complexes 4a-b were determined. The use of the hexafluoroantimonate counterion and solvent mixtures containing toluene both proved crucial in obtaining single crystals; toluene is incorportated into the crystal lattices.
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  • 33
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    Berichte der deutschen chemischen Gesellschaft 128 (1995), S. 1095-1103 
    ISSN: 0009-2940
    Keywords: Zinc complexes ; Tridentate ligands ; Tris(pyrazolyl)methane ; Reactivity ; Structure ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Tris(pyrazolyl)methane ligands in which two or three of the pyrazole carbon atoms bear organic substituents (L1-L7) were synthesized from chloroform and the corresponding pyrazole under phase transfer conditions. Their behavior towards zinc salts was found to span the range from no reaction at all to hydrolytic destruction. One hydrolysis product isolated and structurally characterized was the perchlorate complex [(HPz5)3Zn-OClO3]ClO4 (1), other ones were the 2:1 complexes (HPz3)2ZnBr2 (2) and (HPz6)2Zn(NO3)2 (3, HPzn = substituted pyrazole). Zinc perchlorate and tris(trimethylpy-razolyl)methane (L2) formed the octahedral binary complex [L22Zn](ClO4)2 (4) as evidenced by a structure determination. Zinc halides produced the 1:1 complexes L1 · ZnBr2 (5), L4 · ZnCl2 (6), and L4 · ZnBr2 (7), which according to the structure determinations of 6 and 7 contain tetrahedral ZnN2Hal2 units with only bidentate tris(pyrazolyl)methane ligands. In contrast, the zinc nitrate complex L4 · Zn(NO3)2 (8) was found to have an octahedral structure with mono- and bidentate nitrate and tridentate L4. The bromide complex 7 was converted by silver perchlorate hydrate into the labile compound [L4 · ZnBr]ClO4 (9) and then into the unstable product [L4 · Zn-OH2](ClO4)2 (10), both presumed to contain zinc in a tetrahedral ZnN3Br or ZnN3O environment, respectively. The ease of hydrolytic self-destruction prevented the exploitation of the reactivity of 9 and 10 in analogy to that of the corresponding tris(pyrazolyl)borate zinc complexes.
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  • 34
    ISSN: 0009-2940
    Keywords: Metallomacrocycles ; Nickel complexes ; Complexation reactions ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The reactions between alkali and alkaline earth metal ions and nickel(II) macrocycles based on S-alkylated isothiosemi-carbazides with different crown ether cavity size were studied in propylene carbonate by spectrophotometric and calorimetric titrations. Metallomacrocycles 1 and 2 exhibit normal behavior on 1:1 complexation with alkali- and alkaline earth metal ions and resemble in this respect 15C5 and 18C6, respectively. The most stable complexes are formed by these “ligands” when the diameter of the cation and the crown ether hole have approximately the same size. The most striking feature of the complexation processes studied is the formation of 1:2 metal-ligand associates even in the case of the smallest cations. These associates are very different from “normal” crown ether sandwich complexes. In reality, the particle formed is an associate between a 1:1 complex, in which the corresponding metal ion is well accommdated inside the ligand cavity, and a second metallomacrocyclic ligand. Their formation is disfavored by enthalpic contributions. A special kind of “switch” from these associates to normal sandwich complexes takes place in the case of 1, when the cation diameter compared to hole size increases. The macrocycle 2 forms this kind of associates with all akali and alkaline earth ions.
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  • 35
    ISSN: 0009-2940
    Keywords: Silicon transition metal complexes ; Metallodisilanes ; Nucleophilic metallation ; Cl/H exchange at silicon ; Raman spectroscopy ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Synthesis and Reactivity of Silicon Transition Metal Complexes, 34[*].  -  Pentachlorodisilanyl and Disilanyl Complexes of Molybdenum and Tungsten: Synthesis, Structure, and Spectroscopic CharacterizationReaction of the lithium metallates Li[M(PMe3)(CO)2C5R5] [M = Mo, W; R = H (1a, b), Me (1c, d)] with Si2Cl6 (2) leads to the formation of the pentachloro(metallo)disilanes 5R5(OC)2(Me3P)M - SiCl2 - SiCl3 (3a - d), which are transformed into the metallo disilanes C5R5(OC)2(Me3P)M - SiH2 - SiH3 (4a - d) on treatment with LiAlH4. The disilanes 4a - d are reconverted into 3a - d in the presence of tetrachloromethane. Extensive spectroscopic investigations (NMR, Raman, and IR spectroscopy) were performed to establish the transition-metal effect especially with respect to the H5Si2 ligand. The molecular structure of C5Me5(OC)2(Me3P)W - SiCl2 - SiCl3 (3d) was determined by single-crystal X-ray diffraction.
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  • 36
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    Berichte der deutschen chemischen Gesellschaft 128 (1995), S. 1137-1139 
    ISSN: 0009-2940
    Keywords: Tetraindane(4) ; Indium(I) ; Mn-Mn bond ; Indium alkyl bridge ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Tetrahedra-tetrakis[tris(trimethylsilyl)methyl]tetraindane(4) (1) reacts with decacarbonyldimanganese(0) to yield the bright red crystalline title compound 2, in which two carbonyl ligands are replaced by two InR fragments. The crystal structure determination of 2 shows two Mn(CO)4 groups (Mn-Mn 313.7 pm) bridged by two monoalkylindium units and a planar Mn2In2 molecular center.
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  • 37
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    Berichte der deutschen chemischen Gesellschaft 128 (1995), S. 1149-1156 
    ISSN: 0009-2940
    Keywords: Selenoaldehyde complex ; Thioselonocarboxylic ester complexes ; Selenetane complex ; Dihydrodiselenine complex ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Pentacarbonyltungsten-coordinated selenobenzaldehyde, [(CO)5W{Se=C(Ph)H}] (1), reacts with tBu-C≡C-SMe (2) by insertion of the C≡C into the Se=C bond to form in a highly regio- and stereoselective manner the α,β-unsaturated thioselonocarboxylic ester complex (Z)(C=C)-[(CO)5W{≡1-Se=C(SMe)C(tBu)=C(Ph)H}] (3). The thioselonocarboxylic ester ligand is cleaved intact from the metal by treatment of 3 with [NEt4]Br. Three complexes are formed in the reaction of 1 with Me-C≡C-SMe (5): the thioselonocarboxylic ester complex [(CO)5W{≡1-Se=C(SMe)C(Me)=C(Ph)H}] (6) as a mixture of the (E) and (Z)(C=C) isomers, a selenetane complex (7) and a dihydrodiselenine complex (8). The product distribution depends on the ratio 1:5 and on the solvent. The reaction of 1 with the bis(organylthio)alkynes RS-C≡C-SR (9) [R = Me (a), iPr (b), 2,6-C6H3Me2 (c)] yields mixtures of the (E) and (Z)(C=C) isomers of the α,β-unsaturated α-organylthio thioselonocarboxylic ester complexes [(CO)5W{≡1-Se=C(SR)C(SR)=C(Ph)H)] (10a-c). In contrast, the reaction of 1 with tert-butoxyethyne, H-C≡C-OtBu (11), affords a bis(pentacarbonyltungsten) 5,6-dihydro-1,2-diselenine complex (12). Compound 12 is probably formed by consecutive reaction of 1 with 11 to give the selonocarboxylic ester complex [(CO)5W{≡1-Se=C(OtBu)C(H)=C(Ph)H}] which then further reacts as a heterodiene by highly regioselective [4 + 2] cycloaddition with the Se=C bond of a second molecule of 1 to give 12. In the reaction of 1 with 5 and 9a the isomer with a trans arrangement of C(=Se)SMe and Ph is the kinetically controlled reaction product [(E)-6 and (Z)-10a, respectively]. The formation of (E)-6 and (Z)-10a is followed by isomerization until an (E)/(Z) equilibrium is reached. Complexes 3 and 7 were characterized by X-ray structural analyses.
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  • 38
    ISSN: 0009-2940
    Keywords: Electrophilic aromatic substitution ; Electrophilic vinylic substitution ; Trialkylstannanes, application of ; Sulfonamides, synthesis of ; Sulfodestannylation, application of ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: A mild and effective method for the preparation of aromatic and olefinic sulfonamides is described. The reaction of trialkylaryl- (4a-f), heteroaryl- (4g), and vinylic stannanes (4h) with sulfuryl chloride and secondary amines provides the corresponding sulfonamides in an ipso-specific manner.
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  • 39
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    Berichte der deutschen chemischen Gesellschaft 128 (1995), S. 1207-1219 
    ISSN: 0009-2940
    Keywords: Ylide-substituted phosphorus ; Phosphorus sulfides ; Phosphorus selenides ; Thioxophosphanes ; Selenoxo-phosphanes ; Dithioxophosphoranes ; Diselenoxophosphoranes ; Alkylation reactions ; Selenadiphosphirane ; 2,5,7-Triselena-1,3,4,6-tetraphosphanorbornane ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Ylidylphosphorus Sulfides, Selenides, Disulfides, Sulfide Selenides, and DiselenidesWe report on the first stable monomeric phosphorus mono-chalcogenides 2, 8 and the first stable dichalcogenides 4, 10 without bulky or intramolecularly coordinating substituents. They are stabilized by a high contribution of the zwitterionic resonance formula, which follows both from the NMR spectra and from an X-ray structure determination. Their preparation starts from triphenylphosphoniumylidyl-dichlorophosphanes 1. For the monochalcogenides they are treated with sodium sulfide or selenide or better with bis(trimethylsilyl) sulfide or selenide. In case of the C-phenyl and C-meta-tolyl representatives and also of the C-trimethylsilyl compound a number of secondary, partly novel products are obtained. - The dichalcogenides result from the reaction with sodium disulfide and diselenide, respectively, or from the oxidation of the monochalcogenides. - Alkylation of the monochalcogenides results in ylidylalkylchalcogenophosphenium salts 13, 15. In solution they are in equilibrium with more or less of the covalent form 14, 16, depending on the anion and on the solvent. Alkylation is often accompanied by secondary reactions. A diselenide loses selenium on alkylation.
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  • 40
    ISSN: 0009-2940
    Keywords: Oxofunctionalization ; Dimethyldioxirane ; Metallo silanes ; Metallo silanols ; Metallo siloxanes ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Synthesis and Reactivity of Silicon Transition Metal Complexes, 3332. Mitteilung: Lit. .  -  Metallo Silanols and Metallo Siloxanes, 8 7. Mitteilung: Lit. .  -  Metallo Silanols of the Type C5R5(OC)2(Me3P)M-SiPh2OH (M = Cr, Mo, W): Preparation According to the Dimethyldioxirane Route and Conversion into Metallo Disiloxanes Herrn Professor Max Schmidt zum 70. Geburtstag gewidmet.The metallo silanes C5R5(OC)2(Me3P)M-SiPh2H (4a-c), are converted into the corresponding metallo silanols C5R5(OC)2-(Me3P)M-SiPh2OH [R = H, M = Cr (6a); R = Me, M = Mo (6b); M = W (6c)] by oxofunctionalization with dimethyldioxirane (5). Treatment of 6b, c with the chlorosilanes Me2Si(R)Cl [R = H (3b), [R = Cl (3c)] in the presence of triethylamine gives access to the metallo disiloxanes C5Me5(OC)2(Me3P)M-SiPh2OSiMe2R (M = Mo, R = H (7a); M = W, R = Cl (7b)]. The structure of tungsten silanol 6c is determined by X-ray diffraction analysis.
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  • 41
    ISSN: 0009-2940
    Keywords: Phosphaalkenes, C-halo, C-metal ; Phosphaacrylic acid ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Thermally and air-stable β-phosphaenones were synthesized by functionalization of Mes*P=CCl2 (1; Mes* = supermesityl = 2,4,6-tri-tert-butylphenyl). At low temperature, 1 was lithiated by halogen-metal exchange with n-butyllithium to give the phosphanylidene carbenoid (Z)-Mes*P=C(Cl)Li [(Z)-2] which reacted with acid chlorides to furnish the C-carbonyl-substituted phosphaalkenes (Z)-Mes*P=C(Cl)R (3: P = COtBu; 4: R = COPh; 5: R = COOEt). The reaction of (Z)-2 with carbon dioxide furnished the carboxylate 6, which was converted by treatment with pivaloyl chloride or trimethylsilyl chloride into the phosphaalkenes 7 and 8 functionalized at the carbon atom by an anhydride or a trimethylsilyl ester function, respectively. Acidification of 6 or hydrolysis of 8 with water in chloroform solution afforded the novel carboxylic acid (Z)-Mes*P=C(Cl)COOH (9). Spectroscopic investigations (NMR, UV, IR) of 3-9 and the X-ray structures of 3 and 4 are presented. Based on these properties and on theoretical calculations, the occurrence of conjugation in the β-phosphaenone system is discussed and compared with the well-known conjugation in normal enones.
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  • 42
    ISSN: 0009-2940
    Keywords: Phosphaalkenes ; Cycloadditions ; Insertion reactions ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The dimethylamino-substituted phosphaalkene 1 reacts with hexafluoroacetone (HFA) with addition at the P=C bond to form the 1,5,2-dioxaphosphorinane 2. The structure of 2 was confirmed by an X-ray crystal structure analysis. The six-membered ring displays an envelope conformation with the phosphorus atom out of the plane, but the phosphorus is disordered over two sites. Reaction of P-trimethylsilyl-substituted phosphaalkenes with HFA proceeds with retention of the P=C double bond and insertion of HFA into the P—Si bond. Two isomeric products are obtained and are characterized by 1H-, 13C-, 19F-, and 31P-NMR spectroscopy, IR spectroscopy, mass spectrometry, and elemental analysis.
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  • 43
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    Berichte der deutschen chemischen Gesellschaft 128 (1995), S. 525-529 
    ISSN: 0009-2940
    Keywords: Copper complexes ; Acetylacetonate ; Alkynes ; 1,4-Diynes ; Titanocenes ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Monomeric (Acetylacetonato)copper(I) Complexes of Alkynes and 1,4-DiynesMonomeric (η2-Me3SiC≡CSiMe3)Cu(acac) (3) is formed by the reaction of dimeric [(η2-Me3SiC≡CSiMe3)CuBr]2 (1) with two equivalents of Na(acac) (2). In a similar manner Me2-Si(C≡CSiMe3)2 (4) reacts with CuCl (5) and 2 to afford Me2Si[(η2-C≡CSiMe3)Cu(acac)]2 (6). In compounds 3 and 6 an alkyne unit is η2-coordinated to a monomeric Cu(acac) moiety with a copper atom in a planar environment. With the organometallic 1,4-diyne (η5-C5H4SiMe3)2Ti(C≡CSiMe3)2 (7), compound [(η5-C5H4SiMe3)2Ti(C≡CSiMe3)2]Cu(acac) (8) is formed. In 8 both Me3SiC≡C ligands of the 3-titanapenta-1,4-diyne fragment are η2-coordinated to a monomeric Cu-(acac) building block. The copper atom in 8 possesses a pseudo-tetrahedral environment (shown by X-ray analysis), built by the two Me3SiC≡C ligands of the (η5-C5H4SiMe3)2-Ti(C≡CSiMe3)2 moiety and the two oxygen atoms of the acetylacetonato ligand. 8 is additionally formed by the reaction of 3 or 6 with 7, or by treatment of [(η5-C5H4SiMe3)2Ti(C≡C-SiMe3)2]CuCl (9) with Na(acac) (2). The application of 3, 6, and 8 as precursors for the preparation of copper films in the CVD process of copper(I) is discussed.
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  • 44
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    Berichte der deutschen chemischen Gesellschaft 128 (1995), S. 551-556 
    ISSN: 0009-2940
    Keywords: Benzyllithium compounds ; Ion pairs ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The solvation and ion pair nature of α-(phenylthio)benzyllithium (2d) in THF solution were investigated by NMR-spectroscopic methods. The effect of additives such as diethylene-glycol dimethyl ether or of 12-crown-4 was studied. The results were compared to those of benzyllithium compounds 4 and 6, containing a pentaoxapentadecane ansa chain. These compounds exist as contact ion pairs in which lithium is held at the anionic carbon. This is reflected in the 6Li,13C coupling and 1H,6Li-HOESY contacts in the NMR spectra.
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  • 45
    ISSN: 0009-2940
    Keywords: Titanocene complexes ; Organosulfur ligands ; Ligand transfer ; Organosulfur heterocycles ; Sulfur-sulfur bonds ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The tetrathiaoxalate complex Cp4Ti2C2S4 (1) reacts with an equimolar amount of COCl2 to give the blue-green mononuclear complex Cp2TiC2S4CO (4). This reaction is analogous to the known reactions of 1 with SCl2 or S2Cl2. However, when 1 was treated with equimolar amounts of the bifunctional sulfenyl chlorides 1,2-C2H4(SCl)2 (5), 1,3-C3H6(SCl)2 (6) or 1,2-C6H4(SCl)2 (7), the bi- or monocyclic tetrakisdisulfanes C6H8S8 (9b), C8H12S8 (10), and C14H8S8 (11), respectively, were obtained. The X-ray crystal structure analysis of 11 · CS2 showed that 11 possesses Ci symmetry with a central exocyclic CC double bond similar to tetrathiafulvalenes: C6H4(μ-S2)2C=C(μ-S2)2C6H4.
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  • 46
    ISSN: 0009-2940
    Keywords: Tetracarbonyl(norbornadiene)molybdenum(0) ; Oxidative addition of I2 ; Dihalogeno(bipyridyl)molybdenum(II) complexes ; 7-Coordinated complexes ; Neutral and cationic molybdenum(II) complexes ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The reaction of [Mo(CO)4(C7H8)] (1) with I2 gave the norbornadienemolybdenum(II) complex [Mo(CO)2(C7H8)I2]n≥1 (2), which existed in an equilibrium of two isomeric forms. In acetonitrile, 2 reversibly formed the adduct [Mo(CO)2-(C7H8)(NCCH3)I2] (3), whereas on treatment with 2,2′-bipyridine or 4,4′-di-2,2′-tBu-bipyridine, it gave stable 7-coordinated molybdenum(II) complexes, [Mo(CO)(C7H8)-(C10H8N2)I2] (4) and [Mo(CO)(C7H8)(C10H6tBu2N2)I2] (5), in good yield. In similar reactions, the related dibromomolybdenum compounds [Mo(CO)(C7H8)(C10H8N2)Br2] (6) and [Mo-(CO)(C7H8)(C10H6tBu2N2)Br2] (7) were prepared by oxidation of 1 with two equivalents of CuBr2. The X-ray structural analysis of 6 reveals that the geometry around the molybdenum atom is nearly perfectly pentagonal bipyramidal, with the CO and one of the bipyridyl rings perpendicular to the plane formed by the other ligands. The compounds 5 and 6 react with AgSbF6 by halogen abstraction to give cationic complexes, {[Mo(CO)(C7H8)(C10H8N2)Br]SbF6}n≥1 (8) and {[Mo(CO)(C7H8)(C10H6tBu2N2)I]SbF6}n≥1 (9): In acetone, 8 and 9 reversibly formed the adducts [Mo(CO)(C7H8)(C10H8N2)(acetone)Br]SbF6 (8′) and [Mo(CO)(C7H8)(C10H6tBu2N2)(acetone)I]SbF6 (9′); while on treatment with PMe3, the stable monomeric complexes, [Mo(CO)(C7H8)(C10H8N2)(PMe3)Br]SbF6 (10) and [Mo(CO)(C7H8)(C10H6tBu2N2)(PMe3)I]SbF6 (11), were isolated in almost quantitative yield. In the presence of KBr, compound 8′ reverted to the dibromo complex 6, whereas 9′ reacted to produce a 1:1:2 mixture of 5, 7 and the bromo(iodo) complex [Mo(CO)(C7H8)(C10H6tBu2N2)BrI] (12). The same mixture is available from the reaction of 5 with one equivalent of 7.
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  • 47
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    Berichte der deutschen chemischen Gesellschaft 128 (1995), S. A149 
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
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  • 48
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    Berichte der deutschen chemischen Gesellschaft 128 (1995), S. 1055-1058 
    ISSN: 0009-2940
    Keywords: Aminations ; Palladium catalysis ; Organometallic amines ; Coupling reactions ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The coupling of the iodides 1 with amines under palladium catalysis affords the novel aminated cyclobutadiene derivatives 2 in preparative useful yields.
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  • 49
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    Berichte der deutschen chemischen Gesellschaft 128 (1995) 
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
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  • 50
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    Berichte der deutschen chemischen Gesellschaft 128 (1995), S. 1069-1077 
    ISSN: 0009-2940
    Keywords: Esters, 1-phenylethyl ; Carbanions, α-methyl-α-oxybenzyl, Configurational stability ; Ester - hydroxy ketone rearrangement ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Racemic and optically active 1-phenylethyl esters of pivalic, ( - )-camphanic and 2,4,6-triisopropylbenzoic acid were prepared. The esters 7a of pivalic acid were deprotonated with lithium 2,2,6,6-tetramethylpiperidide (Li-TMP) to form α-oxy-α-methylbenzyllithium compounds which are partly con-figurationally stable prior to acylation with starting material. Camphanic ester (-)-7b cannot be deprotonated by Li-TMP and tBuLi is added to the ester function to afford ketone (-)-12a. 1-Phenylethyl 2,4,6-triisopropylbenzoates 16 were transformed within minutes to carbanions 19 by using sBuLi/TMEDA in THF, hexane, toluene and sBuLi without TMEDA in toluene/20% diethyl ether at -78°C. The carbanions are configurationally stable only in toluene/20% diethyl ether and racemise partly in the other solvents. They react with a variety of electrophiles with either retention [MeOD, AcOD, (MeO)2CO, CICO2Me] or inversion (Me3SnCl) of configuration. Carbanions 19 rearrange on warming to -20°C to hydroxy ketone 24 with racemisation.
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  • 51
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    Berichte der deutschen chemischen Gesellschaft 128 (1995), S. 1131-1133 
    ISSN: 0009-2940
    Keywords: Zirconium(IV) octaethylporphyrin complex ; Dichlorozirconium(IV) porphyrin complex ; Precursor of organometallic compounds ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The synthesis of dichloro(2,3,7,8,12,13,17,18-octaethylpor-phyrinato)zirconium(IV), Zr(oep)Cl2, from zirconium tetrachloride and octaethylporphyrin, H2(oep), is described. The reported synthesis is a new and simple route to this precursor of organometallic compounds. Zr(oep)Cl2 was characterized by elemental analyses, 1H- and 13C-NMR, UV/Vis, and mass spectra. Hydrolysis yielded a mixture of mono- and binuclear hydroxy zirconium(IV) porphyrins.
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  • 52
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    Berichte der deutschen chemischen Gesellschaft 114 (1981), S. 3079-3101 
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Building units for Oligosaccharides, XXIX. Synthesis of a Trisaccharide Chain of N-Acetylglucosamine, Galactose and Rhamnose of an O-Determinant from Escherichia coli. Dependence of Stereoselectivity of the α-Glycoside Synthesis on the Reactivity of the PyranosylhalideThe mercury salt catalysed reaction of substituted α-D-galactosyl halides with the reactive 4-OH groups of the rhamnosides 18 and 19 were studied. The order of reactivity of the halides increases with the following substituents: O-acetyl 〈 O-glucosyl 〈 O-benzyl. The order of selectivity, towards the α-glycoside, was the reverse. The selectivity can be improved by either decreasing the reactivity of the glycosyl halide, in the case of highly reactive hydroxyl groups, or by decreasing the nucleophilicity of the hydroxyl groups, in the case of highly reactive halides. Various trisaccharides, like 58 which represents the repeating-unit of the lipopolysaccharide from Escherichia coli O 75, were synthesized from N-acetylglucosamine, galactose and rhamnose.
    Notes: Die Quecksilbersalz-katalysierte α-Glycosidsynthese von gemischt substituierten α-D-Galactosylhalogeniden mit den reaktiven 4-OH-Gruppen der Rhamnoside 18 und 19 wird untersucht. Die Reaktivität der Halogenide nimmt bei Anwesenheit der folgenden Substituenten zu: O-Acetyl 〈 O-Glycosyl 〈 O-Benzyl. Parallel dazu nehmen die Selektivität und der Anteil and α-Glycosid ab. Notwendige Selektivitätsverbesserungen können bei zu reaktiven OH-Gruppen durch Verminderung der Reaktivität des Glycosylhalogenids, bei zu reaktiven Glycosylhalogeniden durch Verminderung der Reaktivität der OH-Gruppe erzielt werden. Verschiedene Trisaccharideinheiten aus N-Acetylglucosamin, Galactose und Rhamnose werden synthetisiert, wobei 58 einer Teil-struktur der repeating-unit der O-Determinante des Lipopolysaccharids aus Escherichia coli O 75 entspricht.
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  • 53
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    Berichte der deutschen chemischen Gesellschaft 114 (1981), S. 3115-3125 
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Building Units for Oligosaccharides, XXXI. Synthesis of the Repeating-Unit of the O-Specific Chain of the Lipopolysaccharide from Escherichia coli O 75Reaction of the trisaccharidehalide-block 12 with the benzyl rhamnoside 13 gave a tetrasaccharide which, after complete removal of the protecting groups, yielded the branched tetrasaccharid 1 (see german summary). This represents the repeating-unit of the O-specific chain of the lipopolysaccharide from Escherichia coli O 75. A simular reaction between the block 12 and the 8-ethoxycarbonyloctyl rhamnoside 19 leads to the tetrasaccharide 20 which contains a suitable spacer-unit for coupling with a protein to give a synthetic antigen.
    Notes: Durch eine Synthese, bei der der Trisaccharidhalogenid-Block 12 verwendet wird, läßt sich nach vollständiger Entblockierung das verzweigte Tetrasaccharid erhalten, das die repeating-unit der O-spezifischen Kette des Bakteriums Escherichia coli O 75 darstellt. Durch Verknüpfung des Blocks 12 mit dem Rhamnosid 19, einem Glycosid des 8-Ethoxycarbonyloctanols, wurde das spacer-haltige Tetrasaccharid 20 synthetisiert. Dieses ist ein Hapten, das zur Anknüpfung an ein Protein und somit zur Gewinnung eines synthetischen Antigens geeignet ist.
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  • 54
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    Berichte der deutschen chemischen Gesellschaft 114 (1981), S. 3549-3557 
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Substituted Mononucleus Carbonyliron HydridesSubstitution of H2Fe(CO)4 by ligands like L = As(C6H5)3, Sb(C6H5)3 and P(OC6H5)3 in 1:1 ratio leads to fac monosubstituted compounds H2Fe(CO)3L. A 1:2 ratio results in the isolation of disubstituted complexes H2Fe(CO)2L2, L = P(OCH2)3CC2H5, P(OC6H5)3. The structure of H2Fe(CO)3As(C6H5)3 Was elucidated by X-ray analysis.
    Notes: Substitution von H2Fe(CO)4 mit Liganden L = As(C6H5)3, Sb(C6H5)3 und P(OC6H5)3 im Molverhältnis 1:1 Führt zu fac-Monosubstitutionsverbindungen H2Fe(CO)3L. Im Verhältnis 1:2 können trans-Disubstitutionskomplexe H2Fe(CO)2L2, L = P(OCH2)3CC2H5, P(OC6H5)3, erhalten werden. Von H2Fe(CO)3As(C6H5)3 wurde eine Röntgenstrukturanalyse ausgeführt.
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  • 55
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    Berichte der deutschen chemischen Gesellschaft 114 (1981), S. 3518-3532 
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Reactivity of the Silaethene Me2Si=C(SiMe3)2: Thermolysis of (Me3Si)2(Me2XSi)CLi (X e. g. (PhO)2PO2) in the Presence of Silaethene Trapping ReagentsSilaethene Me2Si=C(SiMe32 (1), generated as a reaction intermediate by the thermal elimination of LiX from Me2XSi—CLi(SiMe3)2, combines with the reactants a-b (e. g. Me3Si—Cl, Me3Si—OMe) with insertion in the a-b bond, with a = b-c-H (e. g. CH2=CMe—CH2—H) under ene-reaction and with (e. g. CH2=CR—CR=CH2, O=N=N, Ph2C=NSiMe3, Me3SiN=NSiMe3, PhC=N) under [2 +4]-, [2 + 3]- [2 + 2]- as well as [2 + 2 + 2]-Cycloaddition. Some of the cycloadducts, so obtained, are thermolabile and decompose under cycloreversion, which may lead to the formation of 1 and also to Me2Si=NSiMe3. The following order of relative reactivity of 1-trapping reagents has been found (formation of 1 at -10°C): Me3Si—NMe2 Me3Si—Cl 〈 PhC≡N 〈 1,3-butadien 〈 2.3-Dimethyl-1,3-butadien ≍ isobuten 〈 Me3Si—OMe 〈 Ph2C=NSiMe3 〈 PhN=NPh 〈 Me3SiN=NSin=NSiMe3 ≪ Ph2C=O, Me3SiN=N=N.
    Notes: Das durch thermische LiX-Eliminierung aus Me2XSi—CLi(SiMe3)2 als Reaktionszwischenstufe erzeugbare Silaethen Me2Si=C(SiMe3)2 (1) reagiert mit Reaktanden a-b (z. B. Me3Si—Cl, Me3Si-OMe) unter Insertion in die a-b-Bindung, mit a = b-c-H (z. B. CH2 CMe—CH2—H) unter En-Reaktion und mit (z. B. CH2=CR—CR=CH2, O=N=N, Ph2C=NSiMe3, Me3SiN=NSiMe3, PhC≡N) unter [2 +4]-, [2+3]-[2 + 2]- sowie [2 + 2 + 2]-Cycloaddition ab. Die erhaltenen Cycloaddukte sind zum Teil thermolabil und zerfallen unter Cycloreversion u. a. unter Bildung von 1 sowie auch Me2Si=NSiMe3. Folgende Reihe relativer Reaktivitäten von 1-Fängern wurde gefunden (Erzeugung von 1 bei -10°C): Me3Si—NMe2 Me3Si—Cl 〈 PhC≡N 〈 1,3-Butadien 〈 2,3-Dimethyl-1,3-butadien ≍ Isobuten 〈 Me3Si—OMe 〈 Ph2C=NSiMe3 〈 PhN=NPh 〈 Me3SiN=NSiMe3 ≪ Ph2C=O, Me3Sin=N=N.
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    Berichte der deutschen chemischen Gesellschaft 114 (1981), S. 3533-3548 
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Aliphatic Azo Compounds, XIII: cis- and trans-1-AzonorbornaneThe rates of isomerisation of cis-1-azonorbornane to the trans-isomer at 96.6°C in a series of aprotic solvents follow a linear correalation with ET30. The small slope of the correlation -0.034 argues for isomerisation via semilinearisation in agreement with theory. In protic solvents the isomerisation proceeds faster possibly due to a faster isomerisation by bond rotation which could be favoured by H-bonding. The heat and the activation parameters of the isomerisation and the activation parameters of thermal decomposition of trans-1-azonorbornane allow the construction of a complete enthalpy diagram of this system. The structure of cis-1-azonorbornane was determined by X-ray analysis at -60°C. The observed angle deformations and the normal NN-bond lengths are reproduced by force field calculations.
    Notes: Die Isomerisierungsgeschwindigkeit von cis- in trans-1-Azonorbornan (1) folgt bei 96.6°C linear dem Polaritätsparameter ET30 in verschiedenen aprotischen Lösungsmitteln. Die geringe Steigung -0.034 dieser Korrelation deutet auf einen theoretisch vorgeschlagenen einfachen Inversionsmechanismus. In protischen Lösungsmitteln verläuft die Isomerisierung viel schneller, wofür ein durch H-Drücken begünstigter Rotationsmechanismus Möglich gehalten wird. Reaktionsenthalpie und Aktivierungsparameter der cis-trans-Isomerisierung und die Aktivierungsparameter der Thermolyse von trans-1-Azonorbornan gestatten die Aufstellung eines vollständigen Enthalpiediagramms. Die Struktur von cis-1 wurde durch Röntgenanalyse bei -60°C bestimmt. Die starke Winkeldeformation und der normale NN-Abstand im Kristall werden durch Kraftfeldrechnungen richtig wiedergegeben.
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  • 57
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Metalcarbonyl Syntheses, X: Synthesis of New Niobium and Tantalum Halfsandwich Complexes. Molecular Structure of the Parent Compound (η5-C5H5)Nb(CO)4The halfsandwich complexes (η5-C5H4CH3)Nb(CO)4 (3a), [η5-C5(CH3)5]Nb(CO)4 (3b), (η5-C5H4CH3)Ta(CO)4 (3c), and [η5-C5(CH3)5]Ta(CO)4 (3d) are accessible by reductive high-pressure carbonylation of the corresponding NbV- and TaV precursors (η5-C5R4R′)MCl4 (2a-d). Successive introduction of methyl groups in the cyclopentadienyl ring facilitates the reduction of the halogeno complexes 2a-d; moreover, the niobium complexes are more susceptible to reduction than their tantalum counterparts. Upon photolysis of the carbonyl complexes 3a-d in tetrahydrofuran, the solvens complexes of type (η5-C5R4R′)M(CO)3(THF) (4a-d) are generated. The parent compound (η5-C5H5)Nb(CO)4 (1) has a regular square-pyramidal structure as shown by X-ray analysis.
    Notes: Die Halbsandwich-Komplexe (η-5C5H4CH3)Nb(CO)4 (3a), [η5-C5(CH3)5]Nb(CO)4 (3b), (η5-C5H4CH3)Ta(CO)4 (3c) und [η5-C5(CH3)5]Ta(CO)4 (3d) sind durch reduzierende Hochdruckcarbonylierung der entsprechenden NbV-bzw. TaV-vorstufen (η5-C5R4R′)MCl4 (2a-d) synthetisierbar. Die Reduzierbarkeit der Halogeno-Komplexe, 2a-d, wird durch sukzessive Einführung von Methyl-Substituenten in den Cyclopentadienyl-Ring erleichtert und ist bei den Niob-Verbindungen mit milderen Reduktionsmitteln als bei den analogen Tantal-Komplexen möglich. Bei der Photolyse von 3a-d in Tetrahydrofuran entstehen die Solvens-Komplexe (η5-C5R4R′)M(CO)3(THF) (4a-d). Die Stammsubstanz (η5-C5H5)Nb(CO)4 (1) wurde röntgenstrukturanalytisch untersucht und besitzt eine unverzerrt tetragonal-pyramidale Molekülstruktur.
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  • 58
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    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 114 (1981), S. 3572-3580 
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Complexes of Germanium Dichloride with 1,2-Bis(diphenylphosphino)ethane: A Semi-Chelate and A Double-Ylide1,2-Bis(diphenylphosphino)ethane (dppe) reacts with the germanium dichloride dioxane complex depending on the stoichiometric ratio to give a 1:2 dppe-bridged bis(germylene) complex (1) or a 1:1 complex (2) that shows equilibration of both phosphorus atoms in 31P-NMR. The crystal structure of 2 has been determined from single crystal X-ray data. The compound crystallizes with 8 units dppe-GeCl2· 1/2 C6H6 in a unit cell of symmetry A 2/a-C2h6 in a monoclinic system. The dppe-GeCl2 molecules contain a novel semi-chelating type of coordination of the dppe ligand [distorted Ψ-trigonal bipyramidal coordination at Ge11 with an exceptionally long distance Ge-P(apical)]. 2 thus represents an intermediate structure between chelate complex and phosphorus ylid.
    Notes: 1,2-Bis(diphenylphosphino)ethan (dppe) reagiert mit dem Germanium(II)-chlorid-Dioxankomplex je nach Mengenverhältnis zu einem dppe-verbrückten Bis(germylen)-Komplex (1) oder zu einem 1:1-Komplex (2), der sich durch die Äquivalenz der Phosphanfunktionen in Lösung (31PNMR) auszeichnet. 2 kristallisiert mit 1/2 C6H6 monoklin mit acht Einheiten der Formal dppe-GeCl2· 1/2 C6H6 in der Elementarzelle, Raumgruppe A 2/a-C2h6. Die verzerrt Ψ-trigonal-bipyramidale Koordination um Ge11 mit ungewöhnlich langem Abstand Ge-p(apikal) weist 2 als Komplex mit halb-chelierendem dppe-Liganden aus (Zwischenstellung zwischen Chelatkomplex und einfachem \documentclass{article}\pagestyle{empty}\begin{document}$ \mathop {\rm P}\limits^{\rm + } - \mathop {{\rm Ge}}\limits^{\rm - } - {\rm Ylid} $\end{document}).
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  • 59
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    Berichte der deutschen chemischen Gesellschaft 114 (1981), S. 3581-3588 
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Autoxidation of Trialkylboranes, II: 1H NMR Spectroscopic Investigations on the Mechanism of the Redox Reaction between Trialkylboranes und Dialkyl(alkylperoxy)boranesThe intermolecular redox reaction between dimethyl(methylperoxy)borane and [D9]trimethylborane, triethylborane, tri-n-propylborane, triisopropylborane, and tri-n-butylborane, as well as between [D9]dimethyl(methylperoxy)borane and trimethylborane was investigated directly in an NMR spectrometer. From the CIDNP effects a mechanism of this redox reaction was deduced, which can be considered as generally valid for any reaction between (alkylperoxy)boranes and alkylboranes. According to this mechanism, the alkoxy group of the peroxide is transferred to the boron atom of the alkylborane after homolysis of the O—O bond. The four-coordinate boron compound eliminates instantly an alkyl radical, which forms a radical pair in the singlet state with the boroxyle radical left after the homolysis of the peroxide.
    Notes: Die intermolekularen Redoxreaktionen Zwischen Dimethyl(methylperoxy)boran und [D9]Trimethylboran, Triethylboran, Tri-n-propylboran, Triisopropylboran und Tri-n-butylboran sowie zwischen [D9]Dimethyl(methylperoxy)boran und Trimethylboran wurden in Lösung im 1H-NMR-Spektrometer untersucht. Aus den CIDNP-Effekten wird ein allgemeingültiger Mechanismus der Redoxreaktion zwischen (Alkylperoxy)boranen und Alkylboranen abgeleitet. Danach wird in einem Stoßkomplex zwischen (Alkylperoxy)boranen und Alkylboran durch Homolyse der O—O-Bindung gezielt die Alkoxygruppe des Peroxids auf das Boratom des Alkylborans übertragen. Das vierfach koordinierte Alkoxyalkylboran stößt sofort ein Alkyl-Radikal ab, welches mit dem Boroxylradikal aus der Spaltung des Peroxids zu einem Radikalpaar mit Singulett-Konfiguration der Radikalelektronen zusammenfindet.
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  • 60
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    Berichte der deutschen chemischen Gesellschaft 114 (1981), S. 3589-3598 
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Highly Fluorinated Phosphorus Ylides and Phosphonium SaltsThe (perfluoroalkyl)iodophosphanes n-C6F13PI2 and (n-C6F13)2PI, obtained from n-C6F13I and white phosphorus at 235°C under pressure, are converted into the chlorides n-C6F13PCI2 and (n-C6F13)2PCl with HgCl2. The chlorides are methylated with LiCH3 to form the methylphosphanes n-C6F13P(CH3)2, (6) and CH3P(n-C6F13)2 (5), respectively. Only 6, but not 5, can be quaternized with CH3I to yield a phosphonium salt, [n-C6F13P(CH3)3]I (8). In reactions of 8 with strong bases no corresponding ylide is generated, but a phosphorane n-C6F13P(CH3)4 is obtained instead. More highly fluorinated phosphonium salts could not be prepared. - The Phosphanes (CH3)2PC6F5 (11) and CH3P(C6F5)2 (12) yield onium salts [(CH3)3PC6F5]X (13) and [(CH3)2P(C6F5)2]X (14), resp., when treated with methylating agents. P(C6F5)3 undergoes dearylation reactions under comparable conditions. 13 and 14 are transformed into dark red unstable ylides, which oligomerize with autocondensation and could not be identified. From 12 and C6F5CH2Br a red ylide 17 is obtained, via the onium salt 16, which can be isolated and characterized by spectroscopic data. Stable yellow ylides R3P=CHC6F5 (19a-c, R = CH3, i-C3H7, C6H5) are generated similarly from the phosphonium salts [R3PCH2C6F5]Br. Reduction of the carbanion nucleophilicity by the C6F5 groups appears to prevent autocondensation in these cases.
    Notes: Die aus weißem Phosphor und n-C6F13I bei 235°C unter Druck dargestellten (Perfluoralkyl)iodphosphane n-C6F13PI2 und (n-C6F13)2PI werden mit HgCl2 in die Chloride n-C6F13PCl2 and (n-C6F13)2PCl umgewandelt und diese mit LiCH3 in die Methylphosphane n-C6F13P(CH3)2 (6) und CH3P(n-C6F13)2 (5) übergeführt. Von diesen ist nur 6 mit CH3I quartärisierbar. Das entstehende Salz [n-C6F13P(CH)3)3]I (8) ergibt mit starken Basen nicht das korrespondierende Ylid, sondern das Phosphoran n-C6F13P(CH3)4 (10). Höher fluorierte Phosphoniumsalze sind nicht zugänglich. - Die Phosphane (CH3)2PC6F5 (11) und CH3P(C6F5)2 (12) ergeben mit Methylierungsmitteln noch die Oniumsalze [(CH3)3PC6F5]X (13)bzw. [(CH3)2P(C6F5)2]X (14). P(C6F5)3 erleidet dagegen unter vergleichbaren Bedingungen eine Entarylierung. 13 und 14 werden von starken Basen in tief rote instabile Ylide übergeführt, die durch Autokondensation oligomerisieren und nicht faßbar sind. Mit C6F5CH2Br entsteht aber aus 12 über das Oniumsalz 16 ein rotes Ylid 17, das isoliert und spektroskopisch charakterisiert werden kann. Analog ergeben sich aus Salzen [R3PCH2C6F5]Br stabile gelbe Ylide R3P=CHC6F5 (19a-c, R = CH3, i-C3H7 und C6H5). Die Verminderung der Carbanion-Nucleophilie dieser Ylide durch die C6F5-Gruppe verhindert die Autokondensation.
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    Berichte der deutschen chemischen Gesellschaft 114 (1981), S. 3609-3624 
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Oxidative Additions to 2-Amino-4,4,5,5-tetrakis(trifluoromethyl)-1,3,2-dioxaphospholaneOxidative addition of HF, Cl2 and (CF3)2CO to the title compound 6 furnishes the phosphoranes 2, 9, and 3, respectively. In the case of NH4[OC(CF3)C(CF3)2OH] (4) the hydrospirophosphorane 1 is obtained via a substitution reaction followed by an oxidative addition. Compound 9 is a precursor for the aminotetraalkoxyphosphoranes 5, 8, and the very stable phosphazene 10 which is formed by loss of HCl by thermolysis. Due to a slow ligand exchange the 19F NMR spectrum of phosphorane 3 exhibits eight magnetically non equivalent CF3 groups. By means of 19F homodecoupling experiments extensive through space coupling is found in the molecule. The x-ray structure analysis of 3 shows a slight distortion from the trigonal bipyramidal geometry at phosphorus. For comparison, F2PNH2 and tBu2PNH2 react with (CF3)2 to form (CF3)2C=NH, the aminofluorophosphorane 11, F2P(=O)OCH(CF3)2 (13) bzw. von tBu2P(=o) (12) and tBu2P(=O)OCH(CF3)2 (14), respectively.
    Notes: Durch oxidative Addition von HF, Cl2 und (CF3)2CO and die Titelverbindung 6 entstehen die Phosphorane 2, 9 und 3; mit NH4[OC(CF3)2C(CF3)2OH] (4) wird unter Abspaltung von NH3 und oxidativer Addition das Hydrophosphoran 1 erhalten. Durch Substitution von Chlor lassen sich aus 9 die Aminoalkoxyphosphorane 5 und 8 synthetisieren, während die Thermolyse unter HCl-Abspaltung zu dem äußerst beständigen Phosphazen 10 führt. Verbindung 3 zeigt im 19F-NMR-Spektrum wegen eingeschränkter dynamischer Prozesse acht magnetisch nicht äquivalente CF3-Gruppen. Durch 19F-Homoentkopplungsexperimente werden weitreichende Raumkopplungen nachgewiesen. Die Röntgenstrukturanalyse von 3 ergibt eine annähernd trigonal-bipyramidale Koordination des Phosphors, F2PNH2 und tBu2PNH2, zur vergleichenden Betrachtung herangezogen, reagieren mit Hexafluoraceton unter Bildung von (CF3)2C=NH sowie des Amino-fluorphosphorans 11 und des Phosphorsäureesters F2P(=O)OCH(CF3)2 (13) bzw. von tBu2P(=O)H (12) und tBu2P(=O)OCH(CF3)2 (14).
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    Berichte der deutschen chemischen Gesellschaft 114 (1981), S. 3634-3642 
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Au55[P(C6H5)3]12Cl6- a Gold Cluster of an Exceptional sizeThe reduction of (C6H5)3PAuCl with B2H6 in benzene yields Au9,2[P(C6H5)3]2Cl which is characterized by means of molecular weight determinations as Au55[P(C6H5)3]12Cl6. A simple model, based on an arrangement of close-packed gold atoms, leads to a gold cluster the structure of which is in good agreement with the unusual chemical composition. The Mößbauer spectrum of the compound shows four different kinds of gold atoms: a metallic part (Au13-nucleus), Au atoms coordinated by P(C6H5)3 and Cl ligands, resp., as well as uncoordinated surface gold. The complex can be decomposed by bromine and iodine to (C6H5)3PAuCl, (C6H5)3PAuBr(I), and metallic gold. The thermolysis at 50°C leads to [(C6H5)3P]2AuCl and gold quantitatively.
    Notes: Die Reduktion von C6H5)3PAuCl mit B2H6 in Benzol ergibt Au9,2[P(C6H5)3]2Cl, das mittels Molmassebestimmungen als Au55[P(C6H5)3]12Cl6 charakterisiert wurde. Ein einfaches Modell, beruhend auf einer Anordnung dichtest gepackter Goldatome, führt zu einem Goldcluster, dessen Aufbau mit der ungewöhnlichen chemischen Zusammensetzung in guter Übereinstimmung ist. Das Mößbauer-Spektrum der Verbindung zeigt vier Sorten von Goldatomen: einen metallischen Anteil (Au13-Kern), durch P(C6H5)3-bzw. Cl-Liganden Koordinierte Au-Atome, sowie unkoordi-niertes Oberflächengold. Mit Brom und lod läß sich der Komplex zu (C6H5)3PAuCl, (C6H5)3 PAuBr(I) und metallischem Gold abbauen. Die Thermolyse bei 50°C führt quantitativ zu [(C6H5)3P]2AuCl und Gold.
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    Berichte der deutschen chemischen Gesellschaft 114 (1981), S. 3655-3666 
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Cyanamidium Salts: Their Formation and Molecular StructureThe hexachloroantimonate 6a, is prepared by methylation of di-tert-butylcarbodiimide. According to an X-ray analysis, 6a is not a carbodiimidium salt 1) but a cyanamidium salt with C2ν symmetry of the molecular frame. the cyanamidium salts 6a - j, are prepared either by alkylation of carbodiimides1) or by alkylation of disubstituted cyanamides. Trisubstituted ureas or their thio analogues are not suitable starting materials for the preparation of compounds 6. Reactions of the cyanamidium salts 6 with HCl, water, and diethylamine are described.
    Notes: Das durch Methylierung von Di-tert-butylcarbodiimid erhältliche Hexachloroantimonate 6a liegt nach einer Röntgenstrukturanalyse nicht als Carbodiimidium-1), sondern als Cyanamidiumsalz mit C2ν-Symmetrie des Molekülgerüstes vor. Die Cyanamidiumsalze 6a - j werden außer durch Alkylierung von Carbodiimiden 1) auch durch Alkylierung von disubstituierten Cyanamiden erhalten. Trisubstituierte Harnstoffe oder Thioharnstoffe sind keine geeigneten Ausgangsverbindungen zur Darstellung der salze 6. Es werden Umsetzungen der cyanamidiumsalze 6 mit HCl, Wasser und Diethylamin beschrieben.
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    Berichte der deutschen chemischen Gesellschaft 114 (1981), S. 3674-3683 
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Transition metal Activated Organic compounds, X: Synthesis and Properties of all-α-Poly(N-methylpyrroles)all-α-Poly(N-methylpyrroles) with 2 - 6, 8 and 16 pyrrole units (2 - 8) were synthesized by lithiation of N-methylpyrrole, subsequent reaction with transition metal halides (best yields with NiCl2 as a rule) and repetitions of these processes. These compounds are surprisingly sensitive to heat and light.
    Notes: all-α-Poly(N-methylpyrrole) mit 2 - 6, 8 und 16 Pyrroleinheiten (2 - 8) wurden durch Lithiierung von N-Methylpyrrol, Umsetzung mit Übergangsmetallhalogeniden (beste Ausbeute meist mit NiCl2) und Wiederholungen dieser Prozesse synthetisiert. Diese Verbindungen sind überraschend empfindlich gegen Hitze und Licht.
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    Berichte der deutschen chemischen Gesellschaft 114 (1981), S. 3667-3673 
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Transition Metal Activated Organic Compounds, IX: Synthesis of Polyfurans by Organometallic Oxidative Coupling2,2′- (2a) and 3,3′-bifuran (3), hitherto only accessible by ring-forming syntheses in small yields, and the unknown compounds all-α-terfuran (2b) and all-α-quaterfuran (2c) have been prepared by convenient ring-Connecting syntheses in 85, 46, 16, or 53% yield, respectively. Lithiation of 2a and subsequent reacting with iodine afforded 5-iodo-2,2′-bifuran (6b, 46%). According to competition experiments acidity against n-butyllithium is increasing in the sequence furan 〈 2a, 〈 2b.
    Notes: 2,2′ - (2a) und 3,3′-Bifuran (3), bisher nur durch ringbildende mehrstufige Synthesen in geringer Ausbeute zugänglich, sowie die noch nicht beschriebenen Verbindungen all-α-Terfuran (2b) und all-α-Quaterfuran (2c wurden durch leicht durchführbare ringverknüpfende Synthesen in 85, 46, 16 bzw. 53proz. Ausbeute erhalten. Lithiierung von 2a und Umsetzung mit Iod führte zu 5-Iod-2,2′-bifuran (6b. 46%). Durch Konkurrenzversuche wurde ansteigende Acidität gegen n-Butyllithium in der Reihe Furan 〈 2a 〈 2b festgestellt.
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    Berichte der deutschen chemischen Gesellschaft 114 (1981), S. 3684-3690 
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Metal Hydrazides, XIX: Addition of Bis(diethylaluminio)-substituted Amidrazones and Carbohydrazides to NitrilesAmidrazones and carbohydrazides react with two equivalents of triethylaluminium to give bis (diethylaluminio) derivatives 1 and 7, respectively. In contrast to the corresponding mono(diethylaluminio)derivatives or disodium salts, these are capable of addition to nitriles with formation of N1-(aminomethylene)amidrazones(4; 81 - 95%) or N1-acylamidrazones (8 and 9; 56 - 85%), respectively.
    Notes: Amidrazone und Carbohydrazide reagieren mit zwei Äquivalenten Triethylaluminium zu Bis(diethylaluminio)-Derivaten 1 bzw. 7, die sich anders als die entsprechenden Mono(diethylaluminio)-Derivate oder Dinatriumsalze glatt an Nitrile addieren. Man erhält N1-(Aminomethylen)amidrazone (4; 81 - 95%) bzw. N1-Acylamidrazone (8 und 9; 56 - 85%).
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    Berichte der deutschen chemischen Gesellschaft 114 (1981), S. 3737-3739 
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The Formation of Trichlorosulfonium (IV) Hexafluoroarsenate(V)Sulfur reacts with chlorine and arsenic Trifluoride under pressure to give [SCl3]+[AsF6]-. As an intermediate oxidizing substance [AsCI4]+ is identified by spectroscopy. Depolarization-Raman-spectra confirm the assignment made in literature.
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    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Additions of Carboxylic Acid Dianions to α,β-Unsaturated Carbonyl Compounds - Control of the 1,2-/1,4-Regioselectivity by Steric substituent EffectsDilithium carboxylic acid dianions 1 attack α,β-unsaturated aldehydes (2) 1,2-regiospecifically with formation of the unsaturated β-hydroxy carboxylic acids 3/4. Additionally, the addition of the phenylacetate dianion 1a can be conducted to the threo-isomer with high selectivity by reversible reaction. - α,β-Enones (8) add 1 irreversibly in 1,2- and 1,4-position. Depending on the substitution pattern, the whole range from pure 1,2- to pure 1,4-adduct is covered. The influence of the 1-counterion M and of the solvent is significant; the 1,4-portion increases with the complexing effect of M and with the Lewis-basicity of the solvent.
    Notes: Dilithiumcarbonsäure-Dianionen 1 addieren sich an α,β-ungesättigte Aldehyde (2) 1,2-regiospezifisch unter Bildung der γ,δ-ungesättigten β-Hydroxycarbonsäuren 3/4, wobei im falle des Phenylessigsäure-Dianions (1a)die Addition durch reversible Reaktionsführung zu hoher threo -Selektivität gesteuert werden kann. - α,β-Enone (8) nehmen 1 irreversibel in 1,2- und 1,4-Position auf, wobei nach Maßgabe der Substituenten das gesamte Spektrum von reinem 1,2- zu reinem 1,4-Addukt überstrichen wird. Bei gleichbleibendem Substitutionsmuster steigt der 1,4-Anteil mit der komplexierenden Wirkung der Gegenionen von 1 und mit der Lewis-Basizität des Solvens.
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    Berichte der deutschen chemischen Gesellschaft 114 (1981), S. 3725-3736 
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Synthesis of Medium and Large Rings, II: Cyclodecenes and Cyclodecadienes with Functional Groups by Ring Expansion of CyclooctyneThe Diels-Alder adduct 1 from cyclooctyne and diethyl 3,4-furandicarboxylate gives by photolysis and subseqent thermolysis of the resulting oxaquadricyclane 2 the β,β′-bridged hexano-oxepin 3. Oxidative cleavage of one C=C double bond of 3 leads to the monocyclic cyclodecenone derivative 5 which can be converted to cyclodecadienes of the type 6 with an anellated butenolide ring. 6a - c, are chiral butadiene derivatives. 6a can be cleaved with acid or base to give the cyclodecenone 7 or the dicarboxylic acid 8.
    Notes: Das Diels-Alder-Addukt 1 aus cyclooctin und 3,4-Furandicarbonsäure-diethylester liefert durch Photolyse und anschließende Thermolyse des Oxaquadricyclans 2 das β,β′-überbrückte hexanooxepin 3. Die oxidative Spaltung einer C=C-Doppelbindung von3 führt zum monocyclischen cyclodecenon 5, das sich zu Cyclodecadienen des Typs 6 mit anelliertem Butenolidring abwandeln läßt. 6a - c enthalten eine chirale Butadien-Struktur. Durch Keton- bzw. Säurespaltung von 6a erhält man das Cyclodecenon 7 bzw. die Dicarbonsäure 8. Mögliche Anwendungen des Verfahrens, das die Einführung von funktionellen Gruppen an vier benachbarten C-Atomen des Zehnringes erlaubt, werden besprochen.
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    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Linear Oligophosphaalkanes, III: Syntheses and stereochemistry of Palladium (II) Complexes of chiral Tetraphosphaalkanes H2-nRnP—[CH2]3 — PR′ — [CH2]m — PR′ — [CH2]3 — PRnH2-n(R, R′, = Me, tBu; m = 2, 3; n = 1, 2)The reaction of the chiral tetradentate ligands L of the title with K2PdCl4 affords the complexes Pd(L)Cl2 (2a - e), which for n = 1 may exist as ten (square pyramidal) or six (square planar coordination geometry) isomers. By suitable choice of the substituents R and size of the chelate rings (m + 3) the number of isomers may be reduced to two or three. The detailed investigation of the complexes 2a - e by means of 31P{1H} NMR spectroscopy offers the possibility to identify their stereochemistry. - Monodeprotonation of 2a (R = Me; m = 3; n = 1) and 2d (R = Me; m = 2; n = 1) by KOH or the OH- Form of anion exchange resin yields the phosphido complexes 3a and d (not isolated). Both compounds are oxidized by air with formation of the phosphanoxidophosphane complexes 4a and d, which exist as two or three configurational isomers with units Pd—P(O)Me—.
    Notes: Die Umsetzung der im Titel genannten vierzähnigen Liganden L mit k2PdCl4 liefert die Komplexe Pd(L)Cl2(2a-e)w, die für n = 1 in Form von zehn (quadratisch pyramidale Ligandenanordnung) bzw. sechs (planare Koordinationsgeometrie) Konfigurationsisomeren vorliegen können. Durch geeignete Wahl der substituenten R und der Chelatringgröße (m + 3) läßt sich die Zahl der Isomeren auf zwei bzw. drei reduzieren. Die detaillierte 31P{1H}-NMR-spektroskopische Untersuchung der Komplexe 2a - e erlaubt die Identifizierung der Stereochemie der Isomeren. - Die durch Monodeprotonierung von 2a (R = Me; m = 3; n = 1) und 2d(R = Me; m = 2; n = 1) mit KOH oder der OH- -Form eines Anionentauschers gebildeten Phosphidokomplexe 3a and d werden durch Luftsauerstoff zu den phosphanoxidophosphan-komplexen 4a und d oxidiert, bei denen zwei bzw. drei Konfigurationsisomere mit P-gebundenen Phosphanoxido-Einheiten Pd—P(O)Me— vorliegen.
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  • 71
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    Berichte der deutschen chemischen Gesellschaft 114 (1981) 
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
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  • 72
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    Berichte der deutschen chemischen Gesellschaft 128 (1995), S. 1-9 
    ISSN: 0009-2940
    Keywords: 1-Aza-nido-tetraboranes ; 2,5-Diaza-arachno-pentaboranes ; 2,5-Diaza-nido-hexaboranes ; Boryl[diborane(4)yl]amine ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The Lewis acids RBH2 are added to the basis B-B bond of tri-tert-butylazadiboriridine, NB2tBu3 (1a), to give 5-alkyl-1,2,3-tri-tert-butyl-1-aza-nido-tetraboranes of type 3 (two endo-H atoms at B5) or type 4 (one H atom in a B2-B5 bridging position, one exo-H atom at B5), either as a mixture of 3 and 4 (3, 4b-d: R = Me, tBu, CMe2iPr) or with the isomer 4 in high excess (4e, f: R = Ph, sBu). The reaction of dialkylboranes R2BH with 1a yields 5,5-dialkyl-1,2,3-tri-tert-butyl-1-aza-nido-tetraboranes of type 4 (one H atom in a B2-B5 bridging position; 4g, h: R2 = Et2, cycloocta-1,5-diyl). In boiling THF, trialkylboranes BR3 transform 1a into NB2tBu2R which, expectedly, dimerizes spontaneously to give a dialkyltetra-tert-butyl-2,5-diaza-nido-hexaborane of type 2 (2a, b: R = Me, Et). The products of the addition of aminoboranes H2B=NRR' to 1a are identified as alkyl derivatives of 2,5-diaza-arachno-pentaborane, N2B3tH2tBu3RR' (5a-d, R/R' = H/Pr, H/tBu, Me/Me, Et/Et). The aminoborane H2B = NiPr2 with a sterically more demanding amino group hydroborates the B-B bond of 1a to give the acyclic product iPr2N=BH-B(tBu)-N(tBu)=B(tBu)H (6). In contrast to the B atoms, the N atoms in the electron-deficient cluster skeletons of 2-5 need not take part in (3c,2e) bonds of the s̰ type. The molecular structures of 4c, 5d, and 6 are confirmed by X-ray structural analyses.
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  • 73
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    Berichte der deutschen chemischen Gesellschaft 128 (1995), S. 11-22 
    ISSN: 0009-2940
    Keywords: Thiaselenatelluradiazoles ; Thiaselenatelluratetrazocinium ; Tellurium(IV) compounds ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Treatment of Se(NSO)2 with TeF4 in CH2Cl2 yields the compounds (4a) and (5b), while with TeBr4 after six months (2d) is formed. An almost quantitative yield of Cl4Te2N4S2 (6) is obtained from either Cl6Te2N2S (1a) and (CH3)3SiNSNSi(CH3)3 in CH2Cl2 at 20°C (2 d) or TeCl4 and (CH3)3SiNSO (molar ratio 1:2) in CH2Cl2 at 60°C (3 d). The use of (CH3)3SiOSi(CH3)3 as solvent in the last mentioned procedure gives 1a and small amounts of Cl2Te(NSO)2. Similarly, F2Te(NSO)2 is prepared from TeF4 and (CH3)3SiNSO in CH2Cl2. Dechlorination of 1a with (C6H5)3Sb leads to (2a), which is also produced from TeCl4 and [(CH3)3Si]2NSN[Si(CH3)3]2. When TeF4 is used instead of TeCl4 (molar ratio 3:1) the salt (7a) is formed. Similarly, (7b) is prepared from 2a and AsF5 or Ag+[AsF-6] in SO2. A new method for the preparation of bicyclic type 1 telluraheterocycles involves bromination of 2a yielding Cl2Br4Te2N2S (1b). Dehalogenation with (C6H5)3Sb converts 1b into (2b). When 2b is treated with Br2 in CH2Cl2 an oxidative halogenation takes place with formation of Br6Te2N2S (1c). Metathetical exchange between 2b and Ag+[AsF-6] gives (7c). Isostructural S(NSO)2 reacts with TeCl4 for several weeks at 60°C in CH2Cl2 to form S4N4. TeCl4 and [S5N+5][Te3Cl-3], in contrast to the corresponding reaction with Se(NSO)2. The molecular structures of 4a, 7b, 8, and [S5N+5][Te3Cl-13] have been determined by X-ray diffraction methods. Spectroscopic data for all new compounds are presented.
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    Berichte der deutschen chemischen Gesellschaft 128 (1995), S. 23-27 
    ISSN: 0009-2940
    Keywords: cyclo-Hexatellurium(2+) ; 1,4-Diiodo-cyclo-hexatellurium(2+) ; Hexachlorotungstate(V) ; Tetrachlorooxotungstate(V) ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: WOCl4 reacts at 200°C with tellurium in a sealed, evacuated ampoule with the formation of Te6(WOCl4)2. The structure consists of six-membered tellurium rings in a boat conformation with significant transannular interactions and of pyramidal WOCl4 units which are linked by linear asymmetric O...;W=O bridges to polymeric (WOCl4)n, chains. The observed paramagnetism is consistent with the ionic formulation Te2+6[(WOCl-4)2]n. In the reaction of WCl6, I2 and Te in a 2:1:6 ratio Te6I2(WCl6)2 is formed at 150°C. The crystal structure consists of Te6I2+2cations and of slightly distorted octahedral WCl-6 anions. The Te6I2+2 ions are isostructural with Se6I2+2 and consist of a six-membered ring of Te atoms in the chair conformation with two I atoms bound in the 1,4-positions.
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  • 75
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    Keywords: Ruthenium complexes ; Osmium complexes ; Insertion reactions ; Carbon disulfide ; Carbon dioxide ; Methyl isothiocyanate ; Zwitterionic ligands ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The five-coordinate chloro(hydrido)- and hydrido(iodo)ruthenium(II) and -osmium(II) compounds [MHX(CO)(PiPr3)2] (1, 2, 6, 7) react with CS2 to give the octahedral dithioformato complexes [MCl(CO)(PiPr3)2(η2-S2CH)] (3, 4, 8, 9) in excellent yields. In the initial step, an addition of the heteroallene to the metal center occurs which is followed by insertion of CS2 into the M - H bond. On treatment of the dichlororuthenium(II) derivative [RuCl2(CO)(PiPr3)2] (10), which is prepared from RuCl3 · aq and PiPr3 in methanol, with carbon disulfide insertion into one of the Ru - PiPr3 bonds takes place to give the six-coordinate ruthenium(II) complex 12 with zwitterion -S2CPiPr3+ as a chelating ligand. While the reaction of [OsH(SPh)(CO)(PiPr3)2] (13) with MeSCN leads to addition of the thionitrile to the metal center, the starting material reacts with MeNCS by insertion of the heteroallene into the Os - SPh bond to give two stereoisomers 15a, b, in which the nitrogen atom of the chelate ring is either cis or trans to the hydrido ligand. The octahedral methoxydithiocarbonato- and formatoosmium(II) compounds 16 and 17 are prepared from 2 and CS2 or CO2 in the presence of NaOMe. The crystal and molecular structures of 4 (M = Os), 12 and 15a have been determined.
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    Berichte der deutschen chemischen Gesellschaft 128 (1995), S. 75-79 
    ISSN: 0009-2940
    Keywords: Cobalt(III) complexes ; Dianionic polyolato ligands ; Anhydroerythritol ; α-DMannopyranoside, methyl ; α-DGalactopyranoside, methyl ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Polyol Metal Complexes, XII[1].  -  Synthesis and Structure of Cobalt(III) Complexes with Doubly Deprotonated Anhydroerythritol, Methyl α-DMannopyranoside, and Methyl α-DGalactopyranosideThe polyols anhydroerythritol (AnEryt), methyl α-D-mannopyranoside (Me-α-D-Manp), and methyl α-D-galactopyrano-side (Me-α-DGalp) are deprotonated twice to form the cobalt(III) complexes [(en)2Co(AnErytH-2)]I (1), δ-[(en)2- Co(Me-α-DManp3,4H-2)]ClO4 · NaClO4 · 2H2O (2), and δ-[(en)2Co(Me-α-DGalp2,3H-2)]ClO4·H2O (3), resp., in aqueous, alkaline solutions of trans-[(en)2CoCl2]Cl. The crystal structures of 1-3 have been determined by X-ray diffraction.
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    Berichte der deutschen chemischen Gesellschaft 128 (1995), S. 93-93 
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
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    Berichte der deutschen chemischen Gesellschaft 128 (1995), S. 99-103 
    ISSN: 0009-2940
    Keywords: Tri-tert-butylazadiboriridine ; (Hydroboryl)(methoxyboryl)amine ; 2,3-μ-Hydro-1,2,3-azoniadiborata-l-cyclopropenes ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The B—B bond of tri-tert-butylazadiboriridine [—NR—BR—BR—] (R = tBu; 1) is oxidized by MeOH to give the (hydroboryl)(methoxyboryl)amine H—BR=NR-BR(OMe) (2a). μ-2,3-Hydroazoniadiborata-1-cyclopropenes [=NR—BR(X)—μH—BR=] (3a, 3c-e) are formed by the action of the acids HX upon 1. A similar hydrogen bridge as in 3a-e is formed during the hydroboration of 1 by catecholborane, yielding 3f. A B atom is identified in the products 3a-f to be planarly coordinated by four atoms, two of which are forming a BHB three-center bond with that B atom. This is a novel bonding situation in boron chemistry. The structures of the products are deduced from 1H-, 11B-, and 13C-NMR spectra and are confirmed by X-ray structural analyses of 2a, 3a, and 3c.
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    Berichte der deutschen chemischen Gesellschaft 128 (1995), S. 115-119 
    ISSN: 0009-2940
    Keywords: Polyazamacrocycles ; Dinucleating ligands ; Copper complexes ; Oxalate complexes ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Synthesis and Structure of Dinuclear Copper(II) Complexes of a Novel Hexaaza Macrocycle Containing Bridging Oxalate and Acetate IonsNon-template Schiff base [2 + 2] condensation of pyridine-2,6-dicarbaldehyde with 1,4-diamino-2-butyne yields the hexaazamacrocyclic ligand 1, which is converted to 2 by NaBH4 reduction of the imino groups. Two dinuclear copper(II) complexes of 2 containing oxalate and acetate ions, [(2)Cu2(μ-C2O4)](BPh4)2 (3) and [(2)Cu2(μ-CH3CO2)(OH2)](PF6)2.25-(NO3)0.75 (4), were characterized by X-ray crystallography. The oxalate ligand in 3 forms a (μ-η4:η4) bridge between the copper atoms. Compound 4 contains a syn-anti-bridging acetate ion. The Cu-Cu distances are 5.315 Å in 3 and 4.746 Å in 4, respectively. Oxalate can be separated from other carboxylates in aqueous solution by selective binding to the [(2)Cu2] unit and precipitation of 3.
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    Berichte der deutschen chemischen Gesellschaft 128 (1995), S. 125-129 
    ISSN: 0009-2940
    Keywords: Nickel cluster ; Nickel thiolate ; Hydrogenase ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The tridentate N,O,S-ligand (RS)-2-[(2-mercapto-1-methylamino)ethyl]phenol (rac-1) was prepared from ortho-hydroxy-chloroacetophenone in three steps. When this ligand was treated with nickel(II) acetate, the novel “Ni3S4N3” cluster rac-3 was obtained. The X-ray crystal structure of rac-3 unambiguously revealed the pseudo-C3 symmetric structure of this novel nickel cluster, which is made up by three nickel ions, one sulfide sulfur atom, and three homochiral ligand molecules, each contributing one thiolate sulfur atom and one amine nitrogen atom to the ligation of the metal ions. According to NMR-spectroscopic results, this highly symmetric structure is maintained in solution. The magnetic studies revealed diamagnetic behavior in the solid state, although antiferromagnetic interaction of the metal centers cannot absolutely be excluded.
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    Berichte der deutschen chemischen Gesellschaft 128 (1995), S. 151-155 
    ISSN: 0009-2940
    Keywords: Tripodal ligands ; Phosphane ligands ; Thioethers ; Manganese complexes ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Treatment of fac-[(P2SPh-P,P')Mn(CO)3Br] and fac-[(PS2Ph-P,S)Mn(CO)3Br] [P2SPh: Z = PPh2; PS2Ph: Z = SPh in CH3C-(CH2PPh2)(CH2SPh)(CH2Z)] with silver hexafluorophosphate yields the η3-tripodal manganese complexes [(P2SPh-P,P',S)Mn(CO)3]PF6 (7) and [(PS2Ph-P,S,S')Mn(CO)3]PF6 (9), respectively, whereas the reaction of CH3C(CH2PPh2)2-(CH2SH) with Mn(CO)5Br gives directly [CH3C(Ph2-PCH2)2(CH2S)-P,P',S]Mn(CO)3 (11). Both ionic complexes 7 and 9 undergo stereospecifically ligand substitution upon treatment with Br-, I-, N-3, SCN- and CN- to give syn-fac-[(P2SPh-P,P')Mn(CO)3X] and syn-fac-[(PS2Ph-P,S)Mn(CO)3X] (X = Br, I, SCN, N3, CN) respectively, but the neutral complex 11 fails to undergo such a substitution reaction with these ions. However, reaction of I- with the complex [(PSMe)-P,P',S]Mn(CO)3]BF4 (20) [P2SMe = CH3C(CH2-PPh2)2(CH2SCH3)), which is obtained from the S-alkylation of 11 with (CH3)3OBF4, affords syn-fac-[(P2SMe)-P,P']Mn(CO)3I (22s) exclusively. The possible reaction mechanism of this ligand substitution is discussed.
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    Berichte der deutschen chemischen Gesellschaft 128 (1995), S. 157-161 
    ISSN: 0009-2940
    Keywords: Carbene ligands ; Chromium complexes ; Molybdenum complexes ; Tungsten complexes ; Annulation reaction ; Diels-Alder reaction ; Oxacyclopentenylidene ligands ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Reactions of Complex Ligands, LXI[1]. - Oxacycloalkenylidene Complexes of Chromium, Molybdenum, and Tungsten: Synthesis, Their Annulation with Alkynes and Diels-Alder Reaction with DienesLithiiated propargylic ether 1 reacts with M(CO)6 (M = Cr, Mo, W) to give the 2-oxacyclic carbene complexes 2-4 containing an α,β-double bond and a cyclic acetal structure which serves as a protected benzoyl group. Reaction of the chromium complex 2 with tolan leads to an acyl hydroquinone derivative 5. The tungsten complex 3 undergoes a [4 + 2] cycloaddition with cyclopentadiene to give two diastereomeric oxatricyclic carbene complexes 6 and 7 with an endo/exo selectivity of 3:1. The stereochemistry of the Diels-Alder reaction is controlled by the configuration of the acetal carbon center.
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    Berichte der deutschen chemischen Gesellschaft 128 (1995), S. 183-185 
    ISSN: 0009-2940
    Keywords: 1,4-Diboranaphthalines ; 2,7-Diboradodeca-1,3,9,11-tetraenes ; Cobalt complexes ; Rhodium complexes ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Synthesis and Complexation of 1,4-Dimethyl-2,3-bis(isopropylidene)-1,4-diboratetraline1,4-Dimethyl-2,3-bis(isopropylidene)-1,4-diboratetraline (2) is obtained from o-dilithiumbenzene and 2,5-dimethyl-3,4-bis(chloromethylboryl)-2,4-hexadiene in 61% yield. Its complexation with cyclopentadienylbis(ethene)cobalt leads to the triple-decker bis(η5-cyclopentadienylcobalt)-μ-η6,η6-1,4-dimethyl-2-isopropenyl-3-isopropyl-1,4-dihydro-1,4-dibora-naphthaline (3) in low yield. However, the reaction of 2 with (C5H5)Rh(C2H4)2 and (C5Me5)Co(C2H4)2 originates complexes of a tricyclic ligand formed from 2 via conrotatoric [2 + 2] cycloaddition of the isopropylidene groups. (η5-Cyclo-pentadienylrhodium)-η6-tricyclo-[6.4.0.03,6]-2,4,4,5,5,7-hexamethyl-2,7-diboradodeca-1,3,9,11-tetraene (4), (η5-pentamethylcyclopentadienylcobalt)-η6-tricyclo-[6.4.0.03,6]-2,4,4,5,5,7-hexamethyl-2,7-diboradodeca-1,3,9,11-tetraene (5) and its related dinuclear complex 6 could be isolated in 29, 10, and 31%, respectively. Their constitutions are derived from spectroscopic data and proven by X-ray structure analysis of 4.
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    Berichte der deutschen chemischen Gesellschaft 128 (1995), S. 201-203 
    ISSN: 0009-2940
    Keywords: Nitrogen oxides ; Calculations, ab initio ; Tetranitrogen monoxide ; Dinitrogen monoxide ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Decomposition of Nitrosyl Azide, N4O: Are Cyclic Nitrogen Oxides Existent?The unimolecular decomposition of nitrosyl azide (tetranitrogen monoxide), N4O, was studied at the electron-correlated, spin-restricted RMP2 level with the 6-31G(d,p) and 6-31+G* basis sets. Frequency calculations were performed at 6-31+G* on the optimized structures. It is demonstrated that the experimentally established trans-trans-N4O (Cs) may either interconvert into cis-cis-N4O which upon decomposition forms cyclic N4O (C2v) as an intermediate species to finally give N2O (C∞v) and N2, or trans-trans-N4O may directly dissociate into cyclic N2O (C2v) and N2. All structures determined were rationalized by energy hypersurface calculations.
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    Berichte der deutschen chemischen Gesellschaft 128 (1995), S. 213-220 
    ISSN: 0009-2940
    Keywords: Rhenium complexes ; Alkylidene complexes ; Diazo compounds ; Alkene complexes ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The methylidene complex [(η5-C5H5)Re(NO)(PPh3)(=CH2)]+ PF-6 or the Re—CD2 analog react with diazo compounds N2CHR [R — H, Si(CH3)3, COPh, CO2C2H5] in CH2Cl2 at -80°C to give alkene complexes [(η5-C5H5)Re(NO)(PPh3)(η2-H2C=CHR)]+ PF-6 or D2C=CHR analogs. The two Re=C geometric isomers of benzylidene complex [(η5-C5H5)Re-(NO)(PPh3)(=CHPh)]+ PF-6 and CH2N2 react to give opposite configurational diastereomers of styrene complex [(η5-C5H5)Re(NO)(PPh3)(η2-H2C=CHPh)]+ PF-6. Stereochemical features of these reactions are analyzed in detail, and are interpreted in terms of models involving (a) attack of the diazo compound upon the Re=C face opposite to the bulky PPh3 ligand, (b) an antiperiplanar disposition of the Re=C and C—N2 bonds in the transition state, utilizing the diazo carbon face that minimizes interactions of the substitutent (R) and cyclopentadienyl ligand, and (c) N2 loss from the resulting intermediate [(η5-C5H5)Re(NO)(PPh3)(CHR′CHRN2)]+ PF-6 via a conformer with antiperiplanar P—Re—CHR′—C and Re—CHR′—CHR—N linkages, with anchimeric assistance of the rhenium fragment d orbital HOMO from the backside.
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  • 86
    ISSN: 0009-2940
    Keywords: Borane, [(di-tert-butylphosphanyl)imino](2,2,6,6-tetramethylpiperidino) dimer ; Phosphonium, di-tert-butylmethyl[(2,2,6,6-tetramethylpiperidinoborylene)imino]iodide ; Haloboration ; Hydroboration ; Metal carbonyl complexes of [(di-tert-butylphosphanyl)imino](2,2,6,6-tetramethylpiperidino)borane ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The elements oxygen, sulfur, and selenium add to the P atom of the title borane 1. In contrast to the formation of tmp—B≡N—P(X)tBu2 (X = S, Se), the P oxide (X = O) dimerizes to [tmp—B≡N—P(O)tBu2]2 (5) with an eight-membered flat boat-shaped B2N2P2O2 ring. Borane 1 reacts readily with Mel to yield a phosphonium salt 8 and with BBr3 to give an adduct 9 with a B—P bond. In contrast, bis(dichloroboryl)-methane not only adds to 1 to generate a coordinate B—P bond but also chloroborates the B≡N triple bond, the final product being a new five-membered heterocycle 10. Similarly, the BH3 component of BH3·SMe2 first adds to the P atom of 1 followed by reaction of a second mol of BH3·SMe2 which hydroborates the B≡N triple bond. Finally, metal carbonyl fragments add only to the P atom of 1, demonstrating also that the chemistry of the molecule 1 is dominated by the basicity of its P center.
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  • 87
    ISSN: 0009-2940
    Keywords: Bis(phosphonio)isophosphindolylium cation ; Gold complexes ; Bis(phosphonio)isophosphindolylium carbonylmetallates ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Synthesis and Characterisation of Stable Bis(phosphonio)isophosphindolyliumcarbonylmetallates and a Cationic Bis(phosphonio)isophosphindolylium-Gold ComplexHerrn Professor Alfred Schmidpeter zum 65. Geburtstag gewidmet.Reaction of 1,3-bis(triphenylphosphonio)isophosphindolylium bromide, [L+][Br-] (1a), with Tl[Co(CO)4], Na[MoCp-(CO)3], or Na[WCp(CO)3] (5a-c) yields the corresponding ionic isophosphindolylium-carbonylmetallates, 6a-c. Whereas 1a fails to react with neutral metal carbonyls, a mixture of ionic complexes of the type [LAuX+][AuYZ-] (7a, X, Y, Z = Cl or Br) is formed by reaction with two equivalents of AuCl. Treatment of AuCl with the triflate [L+][OTf-] (1b), which is accessible from 1a via anion metathesis, furnishes [LAuCl+][OTf-] (7b). Both the carbonylmetallate 6c and the complex 7b have been characterized by X-ray structure analyses. 7b displays enhanced reactivity as compared to 1b towards MeOH and H2O, forming the addition products 8 and 9a, b, the latter existing as two different diastereomers. Reactions of 7b with LiF, (Me2N)3P=O, and (Et2N)2C=NH), respectively, proceed via ligand exchange to yield equilibrium mixtures containing the cations [L+] and [LAuCl+].
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  • 88
    ISSN: 0009-2940
    Keywords: Calix[4]arenes ; Supramolecular chemistry ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Preparation of Phosphorus -  and Fluorine-Containing Calix[4]arene Derivatives. Conformational Analysis, Separation of the Conformers, and X-Ray Crystal Structure Analysis of a Cone ConformerHerrn Professor Helmut Werner zum 60. Geburtstag gewidmet.The Calix[4]arene 1 reacts with hexamethyldisilazane or (diethylamino)trimethylsilane to form the bis-trimethylsilyl-ated derivative 2. Treatment of 2 with PF2C1 gives the mono-and bis-difluorophosphites 3 and 4, which react with elimination of Me3SiF or PF3 to yield the monofluorophosphite derivative 5. All four OH hydrogen atoms in 1 are replaced by lithium on reaction with nBuLi with formation of the tetrali-thiated product 6. This has been allowed to react with the Pchlorophosphorinanones 7-9. From 7 the cone conformer 10a is formed, whereas in the case of 8 and 9 a mixture of all four possible conformars 11a-d and 12a-d is obtained. The pure conformers 12a-d are isolated. By refluxing the cone conformer 12a in tetrachloroethane a conformational conversion is effected. In order to evaluate its coordinating ability, 12a was allowed to react with dichloro(cycloocta-1, 5-diene)platinum(II) to form the trans-disubstituted complex 13. In the case of 12a (acetonitrile solvate) a single-crystal X-ray structure analysis has been conducted. The molecule displays a cone conformation, whereby two of the opposing phenyl rings are approximately parallel and the other two approximately perpendicular to each other.
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  • 89
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    Berichte der deutschen chemischen Gesellschaft 128 (1995), S. 289-292 
    ISSN: 0009-2940
    Keywords: η2-Phosphinocarbene complexes of molybdenum and tungsten ; Carbyne complexes ; Chlordimethylphosphane ; Chlordiphenylphosphane ; Electrophilic addition ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Synthesis of Cationic η2-Phosphinocarbene Complexes of Molybdenum and TungstenHerrn Professor Hubert Schmidbaur zum 60. Geburtstag gewidmet.The reaction of chlordimethylphosphane or chlordiphenyl-phosphane and sodium tetraphenylborate with dicarbonyl(η5-cyclopentadienyl)carbyne complexes of molybdenum and tungsten enables the direct conversion of a M=CR group into a M=C(R)—PR2 unit providing dicarbonyl substituted η2-phosphinocarbene complexes in high yields. In the absence of Na[BPh4] a base induced carbonyl carbene coupling reaction affords η3-phosphinoketene complexes.
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  • 90
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    Berichte der deutschen chemischen Gesellschaft 128 (1995), S. 303-307 
    ISSN: 0009-2940
    Keywords: Cobalt dithiolenes ; Charge-transfer complexes ; Electrical conductivity ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Charge-Transfer Complexes of Metal Dithiolenes, XVIII. - Ion Pairs of Dithiolene Cobaltates with Bipyridinium AcceptorsIon pair charge-transfer (IPCT) complexes of the type {A2+[Co(mnt)2]2-}, mnt2- = cis-1,2-dicyano-1,2-ethenedithiolate, A2+ = a bipyridinium derivative, posses IPCT bands in the range from 590 to 950 nm. An X-ray structure analysis of {BQ2+[Co(mnt)2]2-}, BQ2+ = 6,7,8,9-tetrahydrodipyrido[1,2-a:2,1-c][1,4]diazocinium, reveals that the strongly twisted acceptor and planar donor do not form mixed stacks, as usually observed in less twisted systems. Electrical conductivities of pressed powder pellets are in the range of 10-15 to 10-7 Ω-1 cm-1 and do not exhibit a simple correlation with the driving force of electron transfer between the ion pair components. The cis-trans isomerization of an ethene-bridged methyl viologen acceptor leaves the conductivity almost unchanged.
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  • 91
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    Berichte der deutschen chemischen Gesellschaft 128 (1995), S. 321-322 
    ISSN: 0009-2940
    Keywords: Pyridine, trinuclear cobalt cluster ; Heteroarene ligand, σ-N-complexed ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Reaction of [(η5-Cp*)(acac-O,O′)Co] (1) with potassium metal in pyridine results in reductive ligand transfer of the acac ligand to potassium and formation of a mixture of two organocobalt complexes which can be separated from each other by chromatography. Besides a mononuclear complex containing no pyridine unit the trinuclear cobalt cluster [{(η5-Cp*)-Co}3-μ-pyridine] (3) is formed in a cyclometalation reaction in 57% yield. The pyridine ligand in 3 is located on one edge of the Co3 core according to the spectroscopic data and a preliminary X-ray crystal structure analysis.
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  • 92
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    Berichte der deutschen chemischen Gesellschaft 128 (1995), S. 343-350 
    ISSN: 0009-2940
    Keywords: Alkynes ; Palladium complexes ; Phosphane ligands ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Alkynylpalladium compounds trans-PdX(C≡C—R)(PMe3)2 [R = CMe3, X = Cl (1), I (19); R = CMe2OH, X = Cl (2), Br (10), I (11); R = c-Hex, X = Cl (3), Br (12), I (13); R = CHMe2, X = Br (4); R = CH2SiMe3, X = Cl (5), Br (14), I (15); R = COOEt, X = Br (6), I (7); R = Ph, X = Cl (8), I (17); R = n-Pr, X = N3 (16), I (20); R = n-Hex, X = I (21); R = SiPh3, X = Br (22)] and trans-PdX(C≡C—R)(PBu3)2 [R = SiMe3, X = Cl (9), I (18)] as well as trans-PdX(C≡C—R)(PPh3)2 [R = CMe3, X = Br (23); R = CH2SiMe3, X = Br (24), I (25)] are prepared by known methods. Thermal decomposition between 120 and 160°C results in a selective transformation only with trimethylphosphane complexes 1, 2, 10-, and 19. Oxidative trimerization of the alkynyl groups C≡C—CMe2R′ and C≡C—(c-Hex) affording the enediynyl compounds trans-PdX[C(C≡C—CMe2R′) = C(C≡C—CMe2R′)CMe2R′] (PMe3)2 [R′ = Me, X = Cl (26), I (27); R′ = OH, X = Cl (28), Br (29), I (30)] and trans-PdX{C[C≡C—(c-Hex)]=C[C≡C—(c-Hex)] (c-Hex)}(PMe3)2 [X = Br (31), I (32)] appears to be controlled by balanced steric demands of phosphorus and alkynyl substituents. The steric control is investigated by melting) transformable monoalkynyl complex trans-PdI(C≡C—CMe2OH)(PMe3)2 (11) with non-transformable[*] complex trans-PdI[C≡C—(n-Pr)](PMe3)2 (20) to give a mixture (A) of transformed complexes with mixed substituents R. Similar results are obtained in other mixtures, when transformable PdBr(C≡C—SiMe3)(PMe3)[1] is heated with the non-transformable complexes PdBr[C≡C—(n-Pr)](PMe3)2[1] and 20 (mixture B) or transformable PdBr[C≡C—(c-Hex)](PMe3)2 (12) with non-transformable PdBr[C≡C—(n-Pr)](PMe3)2[1] (mixture C).
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  • 93
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    Berichte der deutschen chemischen Gesellschaft 128 (1995), S. 373-378 
    ISSN: 0009-2940
    Keywords: Carbene complexes ; Carbyne complexes ; Carbohydrates ; Diastereoselective addition ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The cationic carbyne complexes [Cp(CO)2M≡CR]+ [BX4]- [M = Mn, X = F: R = Ph (1), Tol (2); M = Re, X = 3,5-C6H2(CF3)2: R = Ph (3)] add the anion of monodeprotonated protected mannofuranose (4a), glucofuranose (4b), and fructopyranose (4c) to the carbyne carbon atom to form the carbohydratocarbene complexes 5a-c, 6a, b, and 7a. With 5b, 5c, and 6b the addition proceeds with retention of configuration at the anomeric center. Due to inversion of configuration in the deprotonation step the complexes 5a, 6a, and 7a are obtained as β-glycosides. The carbene ligand is oxidatively cleaved from the metal by trimethylamine N-oxide or air. Cleavage of the C(carbene)—O bond with reformation of the cation of the carbyne complex 2 is achieved by reaction of 6a with BCl3. Photolysis of [Cp(CO)2Mn=C(Ph)OEt] in the presence of L affords the carbene complexes [Cp(CO)(L)Mn=C(Ph)OEt] [L = P(OMe)3 (11), P(Tol)3 (12)]. Ethoxide abstraction from 11 and 12 by BF3 gives the chiral cationic carbyne complexes [Cp(CO)(L)Mn=CPh]+[EF4]- (13, 14) which add 4a to form the corresponding mannofura-nosylcarbene complexes (15, 16). When 0.5 equivalents of 4a are employed in the reaction with 13, 14 the ratio of diastereomers is 3:2, both for 15 and 16. Complex 11 was characterized by an X-ray structural analysis.
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  • 94
    ISSN: 0009-2940
    Keywords: Lanthanides, organo-, complexes ; Cyclooctatetraenyl complexes ; Benzamidinate ligands ; Diimidophosphinate ligands ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Organometallic Compounds of the Lanthanoids, 89. - Cyclooctatetraenyl Complexes of the Early Transition Metals and Lanthanoids, 6. - (Cyclooctatetraenyl)[N,N′-bis(trimethylsilyl)benzamidinato]- and -[diphenylbis(trimethylsilylimido)-phosphinato] Complexes of the Rare Earths; X-Ray Structural Analyses of (C8H8)Tm[PhC(NSiMe3)2](THF), (C8H8)Lu[4-MeOC6H4C(NSiMe3)2](THF), and (C8H8)Nd[Ph2P(NSiMe3)2](THF)[(C8H8)Ln(μ-Cl)(THF)2]2 or [(C8H8)Ln(μ-O3SCF3)(THF)2]2 (Ln = Y, Ce, Pr, Nd, Sm, Tm, Lu) react with Na[4-RC6H4C(NSiMe3)2] (R = H, OMe, CF3) or Li[PhC(NSiMe3)2] to give the monomeric (cyclooctatetraenyl)lanthanide benzamidinates (C8H8)Ln[4-RC6H4C(NSiMe3)2](THF) [R = H, Ln = Y (1), Ce (4), Pr (6), Nd (8), Sm (10), Tm (12), Lu (15); R = OMe, Ln = Y (2), Ce (5), Pr (7), Nd (9), Sm (11), Tm (13), Lu (16); R = CF3, Ln = Y (3), Tm (14), Lu (17)]. The reaction of [(C8H8)Ln(μ-Cl)(THF)2]2 (Ln = Ce, Pr, Nd, Sm) with Li[Ph2P(NSiMe3)2] in THF leads directly to the monomeric compounds (C8H8)Ln[Ph2P(NSiMe3)2](THF) [Ln = Ce (18), Pr (19), Nd (20), Sm (21)] in good yields. The 1H-, 13C-, 31P- and 29Si-NMR and mass spectra of the new compounds as well as the molecular structures of 12, 16, and 20 are discussed. The Raman spectra of the complexes 1-3, 12, and 14-17 have been studied in detail.
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  • 95
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    Berichte der deutschen chemischen Gesellschaft 128 (1995), S. 423-428 
    ISSN: 0009-2940
    Keywords: Perfluoroethylselenoic acid, -salts, -esters ; Bis(pentafluorophenyl)tellurium(IV) acid, mixed anhydrides, -tellurium(VI) oxide, -tetrakis(trifluoromethylsulfonate), -dihydroxybis(trifluoromethylsulfonate) ; Pentafluorophenyltellurium(IV) oxoacid ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Perfluoroorganochalcogenic Acids in Higher Oxidation StatesPentafluoroethylseleninic acid is oxidized by KMnO4 in slightly alkaline aqueous solution to give K[C2F5SeO3]. With HClO4 the salt is converted into the free acid. Neutralisation of C2F5SeO3H with NaOH, Ag2O, NH3 + H2O provides the corresponding salts. The ethyl ester is made from Ag[C2F5SeO3] and C2H5I. Oxidation of C6F5TeC6F5 with concd. HNO3 yields C6F5Te(OH)ONO2 which on controlled hydrolyses gives (C6F5)2Te(OH)2. Strong acids like HClO4 or H2SO4 form mixed anhydrides like (C6F5)2Te(OH)ClO4 or (C6F5)2Te(OH)OS(O)2OTe(OH)(C6F5)2. For the latter compound a cyclic or noncyclic polycondensate form cannot be ruled out. Acidic 35% H2O2 solution oxidizes (C6F5)2Te(OH)2 at 40°C (48 h) to give (C6F5)2TeO2. This anhydride dissolves only in CF3SO3H forming (C6F5)2Te(OSO2CF3)4. It is soluble in CH3CN and reacts in solution with water to yield (C6F5)2Te(OH)2(OSO2CF3)2. Oxidation of C6F5TeTeC6F5 with concd. HNO3 provides oligomeric [C6F5Te(O)OH]x which still contains some HNO3. A single-crystal X-ray structure determination carried out on [(C6H5)4As][C2F5SeO3] shows convincingly that the central selenium atom is coordinated by three equivalent oxygen atoms with d(Se-O) = 1.614(3) Å, proving that Se has the oxidation state VI.
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  • 96
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    Berichte der deutschen chemischen Gesellschaft 128 (1995), S. 557-560 
    ISSN: 0009-2940
    Keywords: Halfsandwich iridium complexes ; cyclo-Sulfido ligands ; Chalcogen-bridged iridium complexes ; Cubane clusters ; Iridium complexes ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Photolysis or thermolysis of Cp*Ir(CO)2 (1) in the presence of excess sulfur (S8) gives Cp*Ir(CO)(S4) (2a) which is further decarbonylated to [Cp*Ir(μ-S4)]2 (4a). The analogous reaction of 1 with excess selenium leads to Cp*2Ir2(μ-Se)(μ-Se4) (6b). In the case of limited chalcogen supply, the products are [Cp*Ir(CO)(μ-E)]2 [E = S (3a), Se 3b)] and [Cp*Ir(μ-E)]4 [E = S (5a), Se (5b)]. A stepwise formation of the pseudocubane clusters 5a,b from dinuclear precursors is assumed. The solid-state structure of 2a has been determined by X-ray crystallography.
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  • 97
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    Berichte der deutschen chemischen Gesellschaft 128 (1995), S. 575-580 
    ISSN: 0009-2940
    Keywords: Electrophilic aromatic substitution ; Electrophilic vinylic substitution ; Trialkylstannanes, application of ; Arylsulfonates, sodium salts of ; Vinylsulfonates, sodium salts of ; 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, olefinic, and acetylenic sodium sulfonates is described. The reaction of trialkylaryl- (2a-k) and -heteroarylstannanes (4a-d), bis-(1-alkenyl)dibutylstannanes (6a-f), or trialkylalkynylsta manes with trimethylsilyl chlorosulfonate (1) followed by hydrolysis with aqueous NaHCO3 provides the sodium sulfonates in an ipso-specific and in the case of vinylic stannanes stereospecific manner. A comparison of the reactivity of stannylated and silylated olefinic compounds 13 and 14 underlines the greater leaving ability of the stannyl moiety. The in situ preparation of the stannanes makes it possible to apply the synthetic method to natural products such as N-substituted apocodeine (17).
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  • 98
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    Berichte der deutschen chemischen Gesellschaft 128 (1995), S. 541-550 
    ISSN: 0009-2940
    Keywords: Histidine peptides ; Zinc complexes ; Composition ; Solid-state structure ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Nine dipeptides and one tripeptide containing histidine were converted into analytically pure zinc complexes. Four different compositions were observed. The peptides used as or converted into the monoacids LH (HisGly, GlyHis, HisPhe, HisHis) form the compounds ZnL2 (11a, 12-14) and alternatively (HisGly, HisGlyGly) the compounds ZnL(BF4) (11b, 20). The peptides used as amides (HisGlyNH2, HisMetNH2) act as neutral ligands in the compounds ZnL2(ClO4)2 (15, 16). The three remaining peptides (HisAsp, AlaHis, β-AlaHis) behave like diprotonic acids LH2 forming the compounds ZnL (17-19). Spectra and solubilities indicate that complexes 11a, 13, 15, and 16 are mononuclear containing two chelating peptides bound by their amino and imidazole nitrogen atoms. All other complexes seem to be coordination polymers in some of which the amide N and O atoms are involved in the coordination. This was proven by a structure determination for Zn(GlyHis)2 (12) in which the zinc ions are coordinated octahedrally by two histidine N, two amino N, and two amide O atoms of four peptide residues.
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  • 99
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    Berichte der deutschen chemischen Gesellschaft 128 (1995) 
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
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  • 100
    ISSN: 0009-2940
    Keywords: Silicon compounds ; Hydrogen-hydrogen contacts ; Radicals ; ENDOR spectroscopy ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Organosilyl exchange reactions of the extremely electronrich and formally “antiaromatic” 1,4-bis(trimethylsilyl)-substituted 1,4-dihydropyrazine 1 with Ph3SiCl or Me5Si2Cl yielded the new compounds 2 and 3 with triarylsilyl and disilanyl substituents. At δ = 4.53 in CDCl3 compound 3 shows a particularly high-field shifted 1H-NMR resonance for the 1,4-dihydropyrazine protons. In contrast to the planar ring arrangement of 1,4-bis(triisopropylsilyl)-1,4-dihydropyrazine 4, the crystal structure determination of the 2,5-dimethylated analogue 5 as obtained by reductive silylation exhibits a pronounced boat conformation of the heterocycle due to steric repulsion between the substituents, the closest H…H (CH3/ CH) contact being 211 pm. Despite the sizeable structural differences between 4 and 5 both compounds are reversibly oxidized at very negative potentials, at -0.90 and -0.85 V vs. Fc+/0, respectively, It appears that the electrochemical behavior of this class of compounds is determined ***primarly by the configuration at the nitrogen centers and less by the ring conformation. Compound 4 reacts with C60 under EPR-detectable electron exchange to afford 4+* and C-*60. The radical cation 4+* generated separately via oxidation with iodine was characterized by low-temperature UV/Vis and ENDOR spectroscopy. An ENDOR spectrum revealing silylalkyl coupling was also obtained for the related radical cation of reversibly oxidizable 1,1′ -bis(tert-butyldimethylsilyl)-1,1′,4,4′ -bipyridylidene (8).
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