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  • Life and Medical Sciences  (629)
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  • 1996  (1,550)
  • 101
    Electronic Resource
    Electronic Resource
    Twofold Insertion of Isocyanides into the Ga—Ga Bond of Tetrakis[bis(trimethylsilyl)methyl]digallane(4) (1996)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 129 (1996), S. 897-901 
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    ISSN: 0009-2940
    Keywords: Gallium-Gallium bond ; Isocyanide insertion ; 1,4-Diazabutadiene derivatives ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Tetrakis[bis(trimethylsilyl)methyl]digallane(4) (1) reacts with tert-butyl or aryl=isocyanides [aryl = phenyl, o-methylphenyl, o-methoxyphenyl, p-methoxyphenyl) by a twofold insertion of the central carbon atoms into the Ga-Ga bond and formation of C-C single bonds. 1,4-Diazabutadiene derivatives bound to two R2Ga groups are formed (2-6), which in contrast to an aluminium analog exhibit only weak interactions between the imine nitrogen atoms and the coordinatively unsaturated gallium atoms as indicated by NMR spectroscopy and the long Ga-N distances in the molecular structures of three products: 2 (R = C6H5), 4 (R = o-MeOC6H4), and 6 (R = CMe3).
    Additional Material: 3 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19961290804
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  • 102
    Electronic Resource
    Electronic Resource
    Semiconductor-Catalysed Photoaddition: γ,δ-Unsaturated Amines from Cyclopentene and Schiff BasesHeterogeneous Photocatalysis, XIV. - Part XIII: Ref.[10b].Dedicated to Professor Max Herberhold on the occasion of his 60th birthday. (1996)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 129 (1996), S. 925-932 
    Details
    ISSN: 0009-2940
    Keywords: Cadmium sulfide ; Paired photoelectrolysis ; γ,δ-Unsaturated amines ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Irradiation of methanolic cadmium sulfide suspensions in the presence of Schiff bases and cyclopentene opens an easy access to new γ,δ-unsaturated amines. Their formation can be described as a kind of paired photoelectrolysis induced by the photogenerated electron-hole pair trapped at reactive surface sites of CdS. At the reductive site the imine is converted to an α-aminobenzyl radical by a proton-coupled electron transfer, while at the oxidative site cyclopentene is transformed to the cyclopentenyl radical through deprotonation of the intermediate radical cation. C-C coupling of these radicals affords the addition products. Competitive dimerisation of the radicals produces hydrodimers of the imines and dehydrodimers of the olefin, as demonstrated in the case of 1-phenylcyclohexene. Using optical active imines, we found no significant diastereoselectivity. In the absence of an olefin the alcoholic solvent was added to the imine. The molecular structure of one hydrodimer was resolved by X-ray analysis. When CdS/Pt was used as photocatalyst, hydrolysis products of the imine were formed, suggesting involvement of an intermediate OH radical.
    Additional Material: 2 Ill.
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    URL: http://dx.doi.org/10.1002/cber.19961290808
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  • 103
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    Organoamido- and Aryloxo-lanthanoids, 14Part 13: Ref.[1].. Organometallic Compounds of the Lanthanoids, 106Part 105: Ref.[1].. Synthesis and Characterisation of Complexes of Lanthanoid Pyrazolates with 1,2-Dimethoxyethane and the X-Ray Structures of (1,2-Dimethoxyethane-O1:O2)(1,2-dimethoxyethane-O1)tris(3,5-diphenylpyrazolato)erbium(III) and catena-Poly[tris(3,5-di-tert-butylpyrazolato)-μ-(1,2-dimethoxyethane-O1:O2)-neodymium(III)] (1996)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 129 (1996), S. 953-958 
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    ISSN: 0009-2940
    Keywords: Lanthanum complexes ; Neodymium complexes ; Erbium complexes ; Pyrazolate, 3,5-di-tert-butyl-, complexes of ; Pyrazolate, 3,5-diphenyl-, complexes of ; 1,2-Dimethoxyethane, complexes of ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The complexes [Ln(Ph2pz)3 (DME)2] and [Ln(tBu2pz)3 (DME)] (Ln = La, Nd, Er; Ph2pzH = 3,5-diphenylpyrazole; tBu2pzH = 3,5-di-tert-butylpyrazole; DME = 1,2-dimethoxyethane) have been prepared by reaction of the lanthanoid metal with bis(pentafluorophenyl)mercury and the pyrazole in DME. The molecular structures of [Er(Ph2pz)3 (DME)2] (3) and [Nd(tBu2pz)3 (DME)]∞ (5) have been determined by X-ray diffraction. Complex 3 has nine-coordinate Er with three chelating Ph2pz ligands and one chelating and one η1-bound DME. There is a trigonal prismatic arrangement of the oxygen donors and the centres of the N - N bonds. 5 was found to be a linear polymer with transoid DME ligands bridging Nd(tBu2pz)3 units in a novel manner. The centres of the N - N bonds (which are essentially coplanar with Nd), and the oxygen donor atoms adopt an arrangement intermediate between trigonal-bipyramidal and square-pyramidal [O - Nd - O 153.5(2)°].
    Additional Material: 5 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19961290812
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  • 104
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    Control of Regioselectivity in the Transition-Metal-Catalysed Conjugate Additions of Alkylaluminium Compounds and Methyltitanium Ate Complexes to Androsta-1,4-diene-3,17-dione (1996)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 129 (1996), S. 963-966 
    Details
    ISSN: 0009-2940
    Keywords: Steroids ; Androsta-1,4-diene-3,17-dione ; Conjugate addition ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: By a variation of the nature of the reagent system conjugate addition to the cross-conjugated steroidal dienone 1 occurs selectively either at C-1 or at the sterically hindered C-5. With Me3Al or Me4AlLi in the presence of catalytic amounts of Cu1 salts, a high regioselectivity (up to 97:3) in favour of position 1 is achieved. Application of ate complexes of aluminium and titanium in the presence of Ni(acac)2 as catalyst, however, leads to a reversal of the regioselectivity in favour of position 5 (up to 11:89). Aluminium and titanium ate complexes are efficient reagents in the Ni(acac)2-catalysed conjugate addition to sterically hindered enones.
    Additional Material: 2 Tab.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19961290814
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  • 105
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    Komplexe mit Metall-Phosphor-Dreifachbindungen als mögliche Intermediate der Umsetzungen von Chlorophosphiniden-Komplexen mit Metallaten verschiedener ÜbergangsmetalleHerrn Professor Max Herberhold zum 60. Geburtstag gewidmet. (1996)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 129 (1996), S. 973-979 
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    ISSN: 0009-2940
    Keywords: M2P2 tetrahedral complexes ; Phosphido ligand complexes as intermediates ; Ni2P4O distorted prismane framework ; CO incorporation ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Complexes with Metal-Phosphorus Triple Bonds as Possible Intermediates in the Reactions between Chlorophosphinidenes and Metalates of Various Transition MetalsThe reaction of [{M′(CO)5}2PCl] (M′ = Cr, W) with various metalates ([Cp′Mo(CO)3]-, [Cp * Ni(CO)]-, [Cr2(CO)10]2-) yields the M2P2 tetrahedral complexes [(MLn)2(μ,η2- P2){M′(CO)5}2] (MLn = Cp*Ni, M′= Cr (1), W (2); MLn = Cp′Mo(CO)2, M′ = Cr (4); Cp* = η5-C5Me5, Cp* = η5C5H3tBu2) and the cyclo-P4 compound [{Cr(CO)4}(η4-P4){Cr(CO)5}4] 6. As side products the distorted prismane [(Cp*Ni)2{μ4,η4-(P2-O-P2)}{W(CO)5}2] 3 and the diphosphino-methanone complex [{Cp′Mo(CO)2}2{μ4η2-PC(O)P}-{Cr(CO)5}2] 5 are formed. The complexes are characterised by NMR, IR, MS, and X-ray structure analysis (1-5). Studying the reaction pathway provided evidence of phosphido intermediates of the type [LnM≡P→M′Ln].
    Additional Material: 4 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19961290816
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  • 106
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    Chirale Tripod-Liganden mit Phosphit-Donorgruppe: Synthese und KomplexchemieHerrn Prof. Dr. Kurt Dehnicke zum 65. Geburtstag gewidmet. (1996)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 129 (1996), S. 697-713 
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    ISSN: 0009-2940
    Keywords: Chiral tripodal ligands ; Tripod rhodium complexes ; Chiral diphosphanes ; Chiral phosphites ; Ring opening of epoxides ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Chiral Tripodal Ligands Bearing a Phosphite Donor Group: Synthesis and Coordination ChemistryThe mechanism of the reaction of epichlorohydrine (H-CH2Cl) (1) with lithium phosphides is analysed. A neighbouring-group mechanism has been found to be the essential driving force in this reaction. Monophosphanyl alcohols such as HOCH(CH2P(Ph)2)(CH2Cl) (2) and epoxides (Ph)2PCH2- (3) are characterized as intermediates. The mechanism leads to a rapid one-pot method for the synthesis of chiral racemic as well as enantiomerically pure bis(phosphanyl) alcohols HOCH(CH2PR2)(CH2PR2′) (4). The resulting bis(phosphanyl) alcohols 4 react easily with X2PCl (X = Cl; Ph; or X2 = 1,2-ethanedioxy-2,2′-biphenyldiyldioxy-) to yield the mixed donor group tripodal ligands X2POCH(CH2PR2)(CH2PR′2) (5, 6) containing both phosphite, phosphinite or phosphorodichloridite and phosphane donor groups. The identity of these compounds were proved by 1H-, 31P- and 13C-NMR spectroscopy, mass spectra, microanalysis as well as X-ray analysis. The coordination capabilities of these novel ligands are demonstrated by the synthesis and characterization of a (cyclooctadiene)rhodium complex {[(5c)Rh(I)COD]PF6} (7) of the ligand 5c, exhibiting the typical hetero-bicyclooctane tripod metal cage of this type of tripod complexes.
    Additional Material: 7 Ill.
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    URL: http://dx.doi.org/10.1002/cber.19961290617
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  • 107
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    Silyl Triflates - Valuable Synthetic Materials in Organosilicon Chemistry (1996)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 129 (1996), S. 733-739 
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    ISSN: 0009-2940
    Keywords: Silyl triflates ; Oligosilanes ; Polysilylated hydrocarbons ; Organosilicon polymers ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The highly reactive silyl triflates R4-nSi(OSO2CF3)n are valuable materials in organosilicon chemistry. Numerous new triflate derivatives of mono-, oligo-, and polysilanes were prepared by stepwise substitution of trifluoromethylsulfonyl groups for phenyl groups or other leaving groups. Conversions of silyl triflates with nucleophiles proceed regioselectively and, in most cases, quantitatively at low temperatures with short reaction times. Therefore, silyl triflates are suitable reagents for the synthesis and functionalization of linear and cyclic oligosilanes. Novel polycarbosilanes, polysilylalkynes, and polysilylphenylenes, which show a regular alternating arrangement of silylene groups and organic units, were prepared from α,ω-bis[(trifluoromethylsulfonyloxy)silyl]-substituted compounds and dinucleophiles. Branched polysilanes and polysilynes were obtained by reductive coupling of polymeric silyl triflates with potassium-graphite.
    Additional Material: 1 Tab.
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    URL: http://dx.doi.org/10.1002/cber.19961290702
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  • 108
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    The First SiH22+ Complex, Dihydridotetrakis(3-picoline)silicon Dichloride-Tetrakis(chloroform), [H2Si(3pic)4]Cl2 · 4 CHCl3: Formation, Chemical Equilibria, and Structural Investigation by NMR Spectroscopy and Single-Crystal X-ray Diffraction (1996)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 129 (1996), S. 765-771 
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    ISSN: 0009-2940
    Keywords: Bis(dichlorosilyl)amine ; Dihydridotetrakis(3-picoline)silicon dichloride-tetrakis(chloroform) ; Dative Si-N interaction ; 1H1H ROESY ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Bis(dichlorosilyl)amine reacts in chloroform solution with 2-picoline to give H3SiCl, H2SiCl2, and HSiCl3, whereas with 3-picoline the two hypervalent silicon compounds H2SiCl2-(3pic)2 and [H2Si(3pic)4]Cl2 · 4 CHCl3 containing hexacoordinated Si atoms are formed. These complexes are in a chemical equilibrium with each other in chloroform solution, from which crystals of [H2Si(3pic)4]Cl2 · 4 CHCl3 could be isolated. The crystal structure of the latter was determined by single-crystal X-ray diffraction. The complex can be regarded as an “contact ion trio” of [H2Si(3pic)4]2+ and two Cl- ions. The N-Si bond lengths, r(Si-N) = 196.9(3) and 197.5(3) pm, are similar to those found in neutral hexacoordinated Si complexes. The data obtained from a 1H1H ROESY experiment suggest that dissolution has no significant impact on the molecular structure of [H2Si(3pic)4]Cl2 · 4 CHCl3.
    Additional Material: 6 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19961290706
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  • 109
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    Silver(I) Sandwich Complexes of Oxa-Crowned Derivatives of Dithiomaleonitrile (1996)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 129 (1996), S. 807-814 
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    ISSN: 0009-2940
    Keywords: Silver(I) sandwich complexes ; Crown dithioethers, unsaturated ; Bis(methylthio)maleonitrile ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The coordination chemistry of the four oxa-crowned derivatives of dithiomaleonitrile mn-12S2O2, mn-15S2O3, mn-18S2O4, and mn-21S2O5 as well as of the acyclic bis(methylthio)maleonitrile mn-S2 with AgI was investigated by X ray structural and spectroscopic methods. The 2:1 complexes (ligand/AgI) [Ag(mn-12S2O2)2]PF6, [1]PF6, [Ag(mn-15S2O3)2]PF6, [2]PF6, and [Ag(mn-S2)2]PF6, [6]PF6, and the 1:1 complexes [Ag(mn-15S2O3)]ClO4, [3]ClO4, [Ag(mn-18S2O4)]PF6, [4]PF6, and [Ag(mn-21S2O5)]PF6 [5]PF6, were obtained with AgPF6 or AgClO4 in MeOH. The stoichiometry of the macrocyclic AgI complexes and the coordination mode of mn-S2On+1 coronands (n = 1-4) is determined by the length of the macrocyclic oligoethylene chain. - The mn-crown dithioethers mn-12S2O2 and mn-15S2O3 form with AgPF6 the new sandwich complexes [Ag(mn-12S2O2)2]PF6, [1]PF6, and [Ag(mn-15S2O3)2]PF6, [2]PF6. [1]PF6 crystallises in the triclinic space group P1. In the centrosymmetric cation [1]+ each mn-12S2O2 ligand is coordinated to the AgI centre in an endo manner via both S atoms and one O atom. The distance of the second O atom of mn-12S2O2 to AgI is somewhat longer than a normal Ag-Oether bond. The overall environment around AgI in [1]+ is that of a distorted cubic S4O4 set of donors. [2]PF6 crystallises in the monoclinic space group C2/c. In the centrosymmetric cation [2]+ silver(I) is planar-coordinated by the four S atoms of both mn-15S2O3 molecules. The six O atoms of both mn-15S2O3 ligands show only long-range interactions to the AgI ion. They surround AgI almost vertically to the planar S4 set of donors in a crown-like manner. - The crystal structures of the 1:1 complexes [Ag(mn-18S2O4)]PF6, [4]PF6, and [Ag(mn-21S2O5)]PF6, [5]PF6, consist of linear chain polymers. [5]PF6 forms an N-bridged chain polymer of endocyclic [Ag(mn-21S2O5)]+ units with S1O4NNitrile coordination at the AgI centre. In the 2:1 complex [Ag(mn-S2)2]PF6, [6]PF6, each mn-S2 acts as a monodentate NNitrile donor. - 13C-NMR studies in nitromethane solution confirm that the AgI ions in the complexes of the mn-crown dithioethers remain coordinated. However, the AgI ion in complex of mn-S2 is decoordinated.
    Additional Material: 5 Ill.
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    URL: http://dx.doi.org/10.1002/cber.19961290711
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  • 110
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    Metall-π-Komplexe von Benzolderivaten, 49Part 48: Ref.[1].. Halbsandwichkomplexe des Trimesitylborans Mes3B: Darstellung und Struktur von Mes2B[(η6-Mes)Cr(CO)3], MesB[(η6-Mes)Cr(CO)3]2 und B[(η6-Mes)Cr(CO)3]3. Redoxverhalten und Fragen der intramolekularen Wechselwirkung (1996)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 129 (1996), S. 859-869 
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    ISSN: 0009-2940
    Keywords: (Arene)tricarbonylmetals ; Borane, trimesityl ; Cyclic voltammetry ; MLCT transitions ; EPR spectroscopy ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Metal π Complexes of Benzene Derivatives, 49. - Halfsandwich Complexes of Trimesitylborane Mes3B: Synthesis and Structure of Mes2[B(η6-Mes)Cr(CO)3], MesB[η6-MesCr(CO)3]2, and B[η6-MesCr(CO)3]3. Redox Behavior and Questions of Intramolecular InteractionReactions of trimesitylborane (15) with hexacarbonylchromium (16), under varying conditions of stoichiometry and duration, afford the halfsandwich complexes 15[Cr(CO)3] = 17, 15[Cr(CO)3]2 = 18 and 15[Cr(CO)3]3 = 19, which have been characterized by X-ray structure analysis. As for the free ligand 15, the propeller shape of the complexes 17-19 induces chirality; the respective unit cells contain both enantiomers. The steric demand of the Cr(CO)3 fragments causes significant structural changes of the Mes3B unit: in 17 and 18 the bond lengths B-C are increased and the C-B-C bond angles in the reference plane ER1, which is spanned by the three carbon atoms bonded to boron, deviate from 120°; the largest differences was observed for 18. Coordination of Cr(CO)3 fragments to 15 leads to increased dihedral angles between the reference plane ER1 and the mesityl planes; the values of 50.1° for 15 and 61.8° for 19 are representative. Because of the lower symmetry within 17 and 18, the dihedral angles differ; a maximum of 71.1°, relative to the reference plane, is assumed by the noncoordinated ring of 18. The main objective of the study of 17-19 relates to the question of intermetallic communication between moieties separated by sp2-hybridized boron. According to IR data, interaction between the Cr(CO)3 units appears to be minimal. Cyclovo-Itammetry is more revealing: boron-centered reduction, which occurs at -1.94 V for 15, involves anodic shifts E1/2 (0/-) of + 0.24 ± 0.04 V per Cr(CO)3 unit for 17, 18 and 19. This trend is surprising since with increasing degree of coordination the dihedral angles also increase and, therefore, conjugation between the B(2pz) orbital and the mesitylene π systems decreases. Consequently, the redox shifts reflect competition between conjugative and inductive effects, the latter exceeding the former. Subsequent reduction to the dianions 172- -192- is quasi-reversible at -50°C. Chromium-centered oxidation in the +1 V region yields CV waves that fail to reveal resolved redox splitting δE1/2 between subsequent redox steps. However, based on the current ip(0/-) of one electron reduction, the peak currents for the oxidations of 17, 18 and 19 represent one-, two- and three-electron processes, respectively. Although these waves deviate from ideal reversibility, a gradual shift to more positive potentials and an increase in peak separation is discernible. From these features, the value δE1/2 ≤ 70 mV for subsequent oxidation processes at 18 and 19 may be derived as a crude estimate, attesting to weak interaction between the Cr(CO)3 moieties. The radical anions 15-•, 17-•, 18-• and 19-• were generated electrochemically and studied by means of EPR spectroscopy. The hyperfine coupling constants a(11B) increase in the order 17-• 〈 18-• ≤ 15-• 〈 19-•, which again demonstrates the action of stereoelectronic effects. Proton hyperfine coupling is resolved only for the radical anion 15-• of the free ligand. This implies that for the complex radical anions 17-• -19-•, due to the larger angles between the B(2pz) orbital and the z axes of the mesitylene π systems, conjugation Blarr;mesitylene is diminished. The UV/Vis spectra of 17-19 exhibit MLCT bands, which, relative to (η6-C6H6)Cr(CO)3 (λ = 317 nm), show large bathochrome shifts [λ (17) = 458 nm]. The additional shifts effected by introducing a second and third Cr(CO)3 unit are small however [λ (18) = 491 nm, λ (19) = 516 nm]. The energies ΔEop of the MLCT transitions may be compared to the differences ΔEcv = E1/2 (+/0, metal-centered) - E1/2(0/-, ligand-centered), the quantity δE = ΔEop - ΔEcv representing χout the outer-sphere reorganisation energy. For 17-19, the value δE = 0.18 ± 0.1 eV is thus obtained. Interestingly, for p-Me2NC6H4BMes2 δE = 0.29 eV has been reported, suggesting a similarity between a Me2N substituent and a Cr(CO)3 fragment bound to tris(aryl)borane.
    Additional Material: 8 Ill.
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    URL: http://dx.doi.org/10.1002/cber.19961290720
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    Novel Inorganic (Carbon-Free) Chelate Rings: Tris(chelate) Compounds of [N-(Diphenylphosphinoselenoyl)-P,P-diphenylphosphinoselenoic amidato-Se, Se′] with MIII (M = Sb, Bi, In) (1996)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 129 (1996), S. 919-923 
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    ISSN: 0009-2940
    Keywords: Phosphazene metallacycles ; [N-(Diphenylphosphinoselenoyl)-P,P-diphenylphosphinoselenoic amidato-Se,Se′] chelates ; Inorganic carbon-free chelate rings ; Octahedral MSe6 core (M = Sb, Bi, and In) ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The [(SePPh2)2N]- ligand 1c forms stable tris(chelates) with the SbIII, BiIII, and InIII ions. The crystal and molecular structures of the resulting compounds 3, 4, and 5 were determined by X-ray diffractometry. The coordination geometry around the metal centers can be described as a distorted octahedron. This feature and the results obtained by comparing the structures with their sulfur and oxygen analogs lead us to conclude that in both SbIII and BiIII compounds the arrangement around the metals suggests a stereochemically nonactive electron lone pair.
    Additional Material: 3 Ill.
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    URL: http://dx.doi.org/10.1002/cber.19961290807
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  • 112
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    Preparation, Properties, and Reactions of Metal-Containing Heterocycles, XCVPart XCIV: Ref.[1].. Transition-Metal-Mediated Cyclocotrimerization of Selenophosphinites with Activated AlkynesDedicated to Professor Rudolf Taube on the occasion of his 65th birthday. (1996)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 129 (1996), S. 945-951 
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    ISSN: 0009-2940
    Keywords: Cyclocotrimerization ; Selenophosphinites ; Alkynes, activated ; Selenophenes ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Selenophosphinito complexes (OC)4Mn(η2-Se\documentclass{article}\usepackage{amsmath}\pagestyle{empty}\begin{document}$ \dddot - $\end{document}PR21) (2a, b) [R1 = cyc-Hex (a), tBu (b)] are formed by the reaction of BrMn(CO)5 with the phosphane selenides R21HPSe (1a, b) in the presence of the auxiliary base Et(iPr)2N. According to an X-ray structural analysis, 2a crystallizes in the space group \documentclass{article}\pagestyle{empty}\begin{document}$ P\bar 1 $\end{document} with Z = 2. The dimeric complex [(OC)4Mn(μ-Se\documentclass{article}\usepackage{amsmath}\pagestyle{empty}\begin{document}$ \dddot - $\end{document}PMe2)]2 (4c) is not obtained in a straightforward way. Compound 4c is only obtained via the intermediate Br(OC)4Mn-Se\documentclass{article}\usepackage{amsmath}\pagestyle{empty}\begin{document}$ \dddot - $\end{document}P(H)Me2 (3c) by HBr elimination with nBuLi. Complex 3c is formed by replacement of carbon monoxide in BrMn(CO)5 by Me2HPSe (1c). A dissociative equilibrium between [(OC)4 Mn(μ-Se\documentclass{article}\usepackage{amsmath}\pagestyle{empty}\begin{document}$ \dddot - $\end{document}PMe2)]2 (4c) and the monomeric species (OC)4Mn(\documentclass{article}\usepackage{amsmath}\pagestyle{empty}\begin{document}$ \dddot - $\end{document}2-Se\documentclass{article}\usepackage{amsmath}\pagestyle{empty}\begin{document}$ \dddot - $\end{document}PMe2) was not observed. The cyclocotrimerization of the 〉P\documentclass{article}\usepackage{amsmath}\pagestyle{empty}\begin{document}$ \dddot - $\end{document}Se function with the activated alkynes ZC≡CZ [Z = CO2R2; R2 = Me (d), Et (e), iPr (f), cyc-Hex (g)] was successful only in the case of the cyclohexyl derivative 2a to give the selenaphosphamanganabicycloheptadienes 5d - g. An X-ray structural analysis proved that 5d crystallizes in the space group \documentclass{article}\pagestyle{empty}\begin{document}$ P\bar 1 $\end{document} with Z = 2. Under CO pressure 5d was degraded to the selenophene 6.
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    ansa-Titanocene and -Zirconocene η2-Alkyne Complexes -Synthesis, Spectral Characteristics, and X-ray Crystal Structure (1996)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 129 (1996), S. 959-962 
    Details
    ISSN: 0009-2940
    Keywords: ansa-Zirconocenes ; ansa-Titanocenes ; Alkyne complexes ; Pyridine ligands ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The reduction of the complex [(η5-C5H4)-ansa-(η5-C5H4)]TiCl2 with magnesium in the presence of Me3SiC2-SiMe3 in THF at room temperature gives the ansa-titanocone alkyne complex [(η5-C5H4)-ansa-(η5-C5H4)]Ti(η2-Me3SiC2-SiMe3) (ansa = Me2Si-O-SiMe2, 1). The similar pyridine-stabilized zirconium complexes could be obtained by analogous reactions and addition of pyridine: [(η5-C5H4)-ansa-(η5-C5H4)]Zr(L)(η2-Me3SiC2SiMe3) (ansa = Me2Si-O-SiMe2, L = pyridine: 2; ansa = SiMe2, L = pyridine: 3). All complexes were characterized by spectroscopic methods. An X-ray structure determination of complex 3 was conducted, and the data were compared to those of the complexes rac-(EB-HI)Zr(L)(η2-Me3SiC2SiMe3) [L = (S)-(-)-nicotine: 6, EBHI = ethylenebis(tetrahydroindenyl)] and Cp2Zr(py)(Me3SiC2-SiMe3).
    Additional Material: 2 Ill.
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    Masthead (1996)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 129 (1996) 
    Details
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
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    URL: http://dx.doi.org/10.1002/cber.19961290901
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    Synthesis and Characterisation of Ionic Ozonides with Bisquaternary Ammonium CounterionsDedicated to Professor Max Herberhold on the occasion of his 60th birthday. (1996)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 129 (1996), S. 997-1001 
    Details
    ISSN: 0009-2940
    Keywords: Ionic ozonides ; Ammonium ion, bisquaternary ; C-H…O hydrogen bonds ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The bisquaternary ammonium ozonides Me3N+(CH2)n +NMe3(O3-)2 with n = 3, 4, 6 (1, 2, 3), Me3N+(CH2)3+NMe3(O3-)2 · 3 NH3 (1a), Me3N+(p-Ph)+NMe3(O3-)2 (4) and Me3N+(p-Ph)+NMe3(O3-)2 · NH3 (4a) were obtained in quantitative yields by cation exchange starting from CsO3. The compounds 1a and 3 have been studied by single crystal X-ray analysis. The influence of C-H…O and N-H…O hydrogen bonds on the bond length and the bond angle of the ozonide anion is discussed; earlier results are included. The difference between the two bond lengths within the O3- ion [137.4(3) pm and 129.5(3) pm] in 1a is unexpectedly large. Thermal stabilities determined by DTA/TG methods range from 24-83°C.
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    Hydrolysis of Esters and Amides by the Metallo Nucleophile TpCum,MeZn-OH (1996)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 129 (1996), S. 1025-1028 
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    ISSN: 0009-2940
    Keywords: Zinc hydroxide complexes ; Pyrazolylborate ligand ; Hydrolysis of esters and amides ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The molecular zinc hydroxide complex TpCum,MeZn—OH [1, TpCum,Me = tris(3-cumenyl-5-methylpyrazolyl)hydroborate] is a powerful nucleophile. It effects stoichiometric hydrolysis of activated esters RCO—OX and amides RCO—NHX in nonaqueous media. The cleavage products are TpCum,MeZn—OCOR and HOX or H2NX, resp. Two of them (TpCum,MeZn—OCO—CH2-CH2OH resulting from propiolactone and TpCum,MeZnOCO—CF3 resulting from trifluoroacetamide) were characterized by crystal structure determinations.
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    Activation of Molecular Oxygen by Biomimetic Schiff Base Complexes of Manganese, Iron, and Cobalt (1996)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 129 (1996), S. 1041-1047 
    Details
    ISSN: 0009-2940
    Keywords: Biomimetic catalysis ; Oxygen activation ; Schiff base complexes ; Complexes of Mn, Fe, and Co ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The metal complexes (E,E)-[{diethyl 2,2′-[1,2-phenylenebis(iminomethylidyne)]bis[3-oxobutanoato]}(2-)-N,N′,O3,O3′]manganese (Mn1a), [3,3′]-[1,2-phenylenebis(iminomethylidyne)bis(2,4-pentanedionato)(2-)-N,N′,O2,O2′]manganese (Mn1b), and (Z,Z)-[diethyl 3,3′-(1,2-phenylenediimino)bis(2-cyano-2-propenoato)](2-)-N3,N3′,O1,O1′]manganese (Mn1c) were sythesised and the oxygenation of these complexes was investigated by gas volumetry. All complexes except Mn1c are able to take up oxygen but with different magnitudes. The catalytic activity of the Mn, Co, and Fe complexes of the ligands 1a and 1c and (E,E)-[{diethyl 2,2′-[1,2-ethylenebis(iminomethylidyne)]bis[3-oxobutanoato]} (2-)N,N′,O3,O3′] iron (Fe1d) and [diethyl (all-E)-5,14-dihydro-6,17-dimethyldibenzo[b,i][1,4,8,11]tetraazacyclotetradecine-7,16-dicarboxylato)(2-)-N5,N9,N14,N18]iron (Fe2a) has been compared with respect to the oxidation of hydroquinone by molecular oxygen. The results are interpreted with the aid of electrochemical properties, Lewis acidities, and other relevant factors. However, no simple relationship between the catalytic activity and the other factors could be found.
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    Chiral Homoenolate Equivalents, VPart IV: Ref.[22].. Hydroxylakylation of Lithiated 3-[(S)-2-(Methoxymethyl)pyrrolidino]-1,3-diphenylpropene - An Asymmetric Homoaldol Reaction (1996)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 129 (1996), S. 1161-1168 
    Details
    ISSN: 0009-2940
    Keywords: Homoenolate equivalents, chiral ; Hydroxyalkylation ; 1-Aminoallyl anions, chiral ; Acetoxy ketones, chiral ; Homoaldol reaction, chiral ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The hydroxyalkylation of lithiated 3-[(S)-2-(methoxymethyl)-pyrrolidino]-1,3-diphenylpropene (2) with aldehydes is completely regioselective giving homoaldol adducts in good yields. The simple diastereoselectivity is low with typical ratios ranging between 1:1 and 1:3 with the syn isomer predominating. The induced diastereoselectivity is much higher and is strongly solvent-dependent. The reaction predominantly proceeds according to a metalloretentive mechanism from the si side of the allylic system in THF as well as in TBME. The induced diastereoselectivity obtained by the use of the less solvating TBME is considerably higher than in the strongly solvating THF, selectivities of up to 97% ee being reached.
    Additional Material: 2 Tab.
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    The First Triisopropylstibane Ruthenium(II) and Ruthenium(0) Complexes Including the X-ray Crystal Structure of [Ru(η3-C3H5)2(SbiPr3)2]Dedicated to Professor Markus Wieber on the occasion of his 60th birthday (1996)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 129 (1996), S. 1191-1194 
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    ISSN: 0009-2940
    Keywords: Ruthenium complexes ; Stibane complexes ; Dihydrogen complexes ; Butadiene complex ; π-Allyl complex ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The hydridoruthenium(II) complexes [RuHCl(H2)(SbiPr3)3] (2) and [RuH2(H2(SbiPr3)3] (3), containing dihydrogen as ligand, were prepared from [RuCl2(C8H12)]n (1) as the starting material. Compound 3 reacts with CO by displacement of H2 to yield [RuH2(CO)(SbiPr3)3] (4) and with C2H4 to give both [RuH2(C2H4)2(SbiPr3)2] (5) and [RuH2(C2H4)(SbiPr3)3] (6), the latter as the more stable and isolable product. Treatment of 3 with propene leads to the formation of [Ru(η3-C3H5)2] (7) while the reaction of 3 with butadiene affords the pentacoordinated ruthenium(0) compound [Ru(η4-C4H6)2(SbiPr3)] (8). The molecular structure of the bis-(allyl) complex 7 was determined by X-ray crystallography.
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    Coordination Chemistry with CF Units as σ Donors: Ag+ Complexes of Partially Fluorinated Crown Ethers with Direct Metal-Fluorine Interactions (1996)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 129 (1996), S. 1211-1217 
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    ISSN: 0009-2940
    Keywords: Silver ; Macrocycles ; Cryptands ; Fluorine ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The partially fluorinated cryptands FN2O4 and BenzoFN2O4, which are relatives of the [2.2.1]cryptand, were synthesized in good yields from 1,3-bis(bromomethyl)-2-fluorobenzene and diaza-18-crown-6 or benzodiaza-18-crown-6, respectively. These macrobicyclic ligands form very stable complexes with Ag(I) salts, and it was shown that close fluorinesilver interactions occur in solution as well as in the solid state. Numerous experimental evidence for this is available: NMR competition experiments show that Ag+ complexes of FN2O4 are significantly more stable than those of HN2O4 (the two ligands are identical except that one fluorine atom is replaced by one hydrogen atom in HN2O4); the 1JCF coupling constants of Ag+ · FN2O4 and Ag+ · BenzoFN2O4 are reduced by 10 Hz compared to those of the respective free ligands FN2O4 (1JCF=253 Hz) and BenzoFN2O4. (1JCF=252 Hz). The X-ray crystal structure of Ag+ · FN2O4 revelas short Ag+-F distances [271.4(3) pm]; coupling of the 107,109Ag+ and 19F nuclei is observed in the 19F-NMR spectra (J=24 Hz for Ag+ · FN2O4, J=25 Hz for Ag+ · BenzoFN2O4). The 1H-NMR spectrum of Ag+ ·FN2O4 is very complex and exhibits sixteen unique proton resonances, whose evaluation yielded coupling constants and NOEs, which show that the structure in solution is compatible with the results obtained by the X-ray crystal structure determination.
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    Zinc Complexes of Amino Acids and Peptides, 8[Part 7: Ref.[1].]. Difunctional Dipeptides Containing Cysteine or Histidine: Solution Behavior and Zinc Complextion (1996)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 129 (1996), S. 1243-1249 
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    ISSN: 0009-2940
    Keywords: Dipeptides ; Cysteine ; Histidine ; Zinc complexes ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The dipeptides Ac-Cys-Val-OH (1a) and Ac-His-Val-OH (1b), H-Gly-Cys-OEt (2a) and H-Val-His-OEt (2b) as well as Z-Asp-Cys-OH (3a) and Z-Asp-His-OH (3b) (Z = benzyloxycarbonyl) were prepared, and their zinc complexation was investigated by potentiometric methods. They have in common that in addition to the cysteine thiolate or the histidine imidazole the second amino acid offers one donor function. The complex stabilities are very close to those of the corresponding difunctional derivatives of the single amino acids cysteine or histidine. This indicates the presence of seven- to ten-membered chelate rings.
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    Activation of Carbon Dioxide, VIPart V: Ref.. Ligand Effects in the Catalytic Hydrogenation of Carbon Dioxide to Formic Acid Using in situ Catalysts Formed from [{(cod)Rh(μ-Cl)}2] and Monodentate and Bidentate Phosphorus Ligands (1996)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 129 (1996), S. 91-96 
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    ISSN: 0009-2940
    Keywords: Carbon dioxide, catalytic hydrogenation of ; Ligand effects ; Rhodium catalysts ; Formic acid ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Highly active catalysts for the hydrogenation of CO2 to formic acid in DMSO/NEt3 are formed in situ from [{(cod)Rh(μ-Cl)}2] and various monodentate or bidentate ligands with phosphorus as the donor atom. Formic acid concentrations up to 2.3 · 0.2 mol l-1 can be obtained in less than 6 hours at ambient temperature under a total initial pressure of 40 atm by using rhodium concentrations of 5 · 10-3 mol l-1. The changes in catalytic activities observed upon structural changes of monodentate ligands are discussed in terms of classical ligand parameters like basicity and steric demand of the PR3 group, while with bidentate ligands R2P(CH2)nPR2 the chain length n plays a dominant role for the activity of the catalyst. The effects cannot be explained by a direct impact of the ligand on catalytically active intermediates only, but influences on the formation of these species must also be taken into account.
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    Komplexe von Halogenid-Ionen mit 1-Halogen-2-phenylacetylenen. Kristallstrukturen von PPh4[X(I - C≡C - Ph)4] mit X = Cl, Br, I, von PPh4[Br(Br - C≡C - Ph)4] und von NMe4[F(I - C≡C - Ph)2]Herrn Prof. Dr. H. Brunner zum 60. Geburtstag gewidmet. (1996)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 129 (1996), S. 115-120 
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    ISSN: 0009-2940
    Keywords: Halide complexes of 1-Halogen-2-phenylacetylenes ; Acetylenes, 1-halogen-2-phenyl-, halide complexes of ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Complexes of Halide Ions with 1-Halogen-2-phenylacetylenes. Crystal Structures of PPh4[X(I - C≡C - Ph)4] with X = Cl, Br, I, of PPh4[Br(Br - C≡C - Ph)4], and of NMe4[F(I - C≡C - Ph)2]Herrn Prof. Dr. H. Brunner zum 60. Geburtstag gewidmet.The complexes PPh4[X(I - C≡C - Ph)4] with X = Cl (1), Br (2), I (3), PPh4[Br(Br - C≡C - Ph)4] (4), and NMe4[F(I - C≡C - Ph)2] (5) were prepared from the corresponding salts PPh4X and NMe4F, respectively, with the 1-halogen-2-phenylacetylenes X - C≡C - Ph (X = Br, I) in dichloromethane solutions. 1 - 5 form colourless crystals, which were characterized by vibrational spectroscopy. According to the crystal structure determinations the halide ions in 1 - 4 are coordinated by the halogen atoms of the 1-halogen-2-phenylacetylenes in a tetragonal-pyramidal fashion. The fluoride ion in 5 is only twofold coordinated with a bond angle I - F - I of 110.45°.
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    Metal Complexes with Tetrapyrrole Ligands, LXXPart LXIX: J. W. Buchler, M. Eberle, Chem. Ber. 1995, 128, 1131-1133.. Synthesis, Characterization, and Variable-Temperature 1H-NMR Investigations of Cerium(IV) and Zirconium(IV) Double-Deckers Derived from 2,3,7,8,12,13,17,18-Octaethyl-5-methylporphyrin (1996)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 129 (1996), S. 201-205 
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    ISSN: 0009-2940
    Keywords: Cerium(IV) bis(porphyrinates) ; Zirconium(IV) bis(porphyrinates) ; Porphyrin, 2,3,7,8,12,13,17,18-octaethyl-5-methyl- ; Geometrical isomerism ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The synthesis of bis(2,3,7,8,12,13,17,18-octaethyl-5-methyl-porphyrinato)cerium(IV) and -zirconium(IV) [M(oemep)2; M = Ce, Zr, respectively] is described. The complexes were characterized by UV/Vis and IR spectroscopy and cyclic volt-ammetry. 1H-NMR spectra of the new cerium and zirconium sandwich complexes show that they exist as a mixture of vicinal and transversal isomers due to the rigid square-antipri-smatic coordination geometry found in metal(IV) bis(porphy-rinates). From the temperature dependence of the 1H-NMR spectra the rotational rigidity of the double-decker system was deduced. In toluene, free rotation of the two porphyrin macrocycles with respect to each other does not occur up to 373 K.
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    Hybrid Diborolyl/Dicarbaboranyl Triple-Deckers: [(μ5-Cyclopentadienyl)cobalt][μ,η5-1,3-diborolyl)cobalt[dicarba-heptacarboranyl and -nonacarboranyl ComplexesDedicated to Prof. H. Roesky on the occasion of his 60th birthday. (1996)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 129 (1996), S. 213-217 
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    ISSN: 0009-2940
    Keywords: Triple-decker complexes ; Cobaltadicarba-closo-octaborane ; Cobaltadicarba-closo-decaborane ; Rearrangements ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The three-component reactions of the sandwich anion [(η5-C5H5)Co(η5-Et4MeC3B2)]- (4-H)- and various dicarbaborane anions with metal halides are described. Thus, (4-H)-, nido-4,5-C2B6H9- (5), and CoCl2 form the 30VE triple-decker [η5-C5H5)Co(μ,η5-Et4MeC3B2)Co(η5-2,3-C2B5H7)] (6). An analogous three-component reaction of (4-H)-, arachno-4,5-C2B7H-2 (7), and CoCl2 yields [(η5-C5H5)Co(μ,η5-Et4-MeC3B2)Co(η5-6,9-C2B7H9)] (8), which rearranges on heating (57°C) to give the 1,6-isomer [(η5-C5H5)Co(μ,η5-Et4-MeC3B2)Co(η5-1,6-C2B7H9)] (9) with an activation energy of 127 · 10 kJ/mol. The thermodynamically most stable 1,10-isomer [(η5-C5H5)Co(μ,η5-Et4MeC3B2)Co(η5-1,10-C2B7H9)] (10) is formed by heating of 9 at 180°C. An alternative route to 9 is provided by the reaction of arachno-6,8-C2B7H12- (11) with (4-H)- and CoCl2. The analogous reaction with RhCl3 leads to [(η5-C5H5)Co(μ,η5-Et4MeC3B2)Rh(1,6-C2B7H9)] (15) and unexpectedly to closo-2-(η5-C5H5)Co(1,6-C2B7H9) (12). The constitutions of the described compounds are derived from their 1H-, 11B-, 13C-NMR data as well as mass spectral data. The X-ray structure analyses of 10 and 12 show the expected metal complexes with a CoC2B7H9 framework. In 10 the carbon atoms occupy the capping positions of a bicapped square antiprism. The short Co-Co distance of 3.20 Å is in agreement with the 30VE configuration of 10. In both 10 and 12, the distance from the cobalt to the four-coordinate C4 is the shortest Co-to-cage atom distance.
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    Masthead (1996)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 129 (1996) 
    Details
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19961290301
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    A Synthetic and Theoretical Study of the Aggregation of Amidoaluminium Hydrides: Solid-State Structure of the Trimethylamine Adduct [(Me3Si)2NA1(Cl)(H) · NMe3] (1996)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 129 (1996), S. 545-549 
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    ISSN: 0009-2940
    Keywords: Alane ; Association ; Hydride ; Amido ; Amide ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The amidoaluminium hydride complexes [(Me3Si)2NA1(X)(H) · NMe3], X = H (1), Cl (2), were prepared by the metallation of bis(trimethylsilyl)amine by Al(X)(H)2 · NMe3 (X = H and Cl). The molecular structure of 2 as a monomeric Lewis base adduct with four-coordinate aluminium centres and terminal amido groups was confirmed by X-ray crystal structure determination. We also find that bis(trimethylsilyl)amine forms a thermally stable adduct of alane, (Me3Si)2N(H) · AlH3 (3). Ab initio molecular orbital calculations on the possible products arising from these reactions yielding 1 and 2 revealed that the amido-bridged species, {(μ-H2N)Al(X)H}2 (X = H and Cl), are favoured over nitrogen donor Lewis base adduct formation, H2NAl(X)(H) · NH3 (X = H and Cl), and then chloro-bridged, {H2NAl(μ-X)(H)}2, (X = Cl only), and hydrido-bridged species, {H2NAl(X)(μ-H)}2 (X = H and Cl).
    Additional Material: 2 Ill.
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    URL: http://dx.doi.org/10.1002/cber.19961290511
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    On the Chemistry of Gallium, 8Part 7: Ref.[1].. Synthesis and Structure of [Tris(trimethylsilyl)silyl]-Substituted Gallanes and Gallates (1996)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 129 (1996), S. 561-569 
    Details
    ISSN: 0009-2940
    Keywords: Silylgallanes ; Gallium compounds ; Hydroxygallium compounds ; Gallium alkoxides ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Reaction of lithium tris(trimethylsilyl)silanide · 3 THF with R2GaCl (R = 2,2,6,6-tetramethylpiperidino, Me, Cl) yields tmp2GaSi(SiMe3)3 (3) and R2Ga(THF)Si(SiMe3)3 (R = Me, Cl) (7, 9). Both gallium nitrogen bonds in 3 are cleaved by protic reagents. Depending on the acidity of these agents, either oligomeric gallanes [(RO)2GaSi(SiMe3)3]n (R = Et, H, n = 2, 3) (11, 12) or tetramethylpiperidinium gallates [X3GaSi-(SiMe3)3]- (X = OPh, Cl) (13, 14) are formed. Hydroxide 11 adds lithium hydroxide to afford the mixed lithium gallium hydroxide 15. Single-crystal X-ray diffraction studies confirm the suggested constitutions. The gallium-silicon bond can adopt values between 236 and 247 pm. Here electronic influences of the substituents on the gallium center are of great importance as well as their steric demand. This is underlined by quantum chemical calculations on the ab initio (SCF) level.
    Additional Material: 7 Ill.
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    Palladium-Copper-Catalyzed Coupling of Tricarbonylchromium-Complexed Phenylacetylene with Iodoarenes - A Facile Access to Alkynyl-Bridged Cr(CO)3-Complexed Benzenes (1996)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 129 (1996), S. 607-613 
    Details
    ISSN: 0009-2940
    Keywords: Arene complexes ; Chromium compounds ; Alkynes ; Catalysis ; Coupling reactions ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The palladium-copper-catalyzed coupling of the tricarbonyl-chromium-complexed chlorobenzene 1 with (trimethylsilyl)-acetylene gives tricarbonyl{η6-[(trimethylsilyl)ethynyl]-benzene}chromium(0) (2) in high yield. After desilylation of 2 tricarbonyl[η6-(ethynylbenzene)]chromium(0) (3) is obtained quantitatively. Using the palladium-copper-catalyzed methodology, we can readily introduce Cr(CO)3-complexed phenylethynyl units by a multifold coupling of 3 with iodobenzene, 1,2-, 1,3-, 1,4-di- and 1,3,5-tiiodobenzene (4a-e) or 1 to give polynuclear Cr(CO)3-complexed (phenylethynyl)benzenes 5a-e and doubly Cr(CO)3-complexed tolane 6 in good to moderate yield. The crystal structure analyses of μ3-{η6:η6:η6[1,3,5-benzenetriyltris(2,1-ethynediyl)]tris(benzene)}tris[tricarbonylchromium(0)] (5e) and μ-{η6:η6-[1,2-ethynediylbis(benzene)]}bis[tricarbonylchromium(0)] (6) reveal that the tricarbonylchromium tripods in the same molecule are arranged in antiparallel syn-eclipsed conformations. The Eglington coupling of 3 affords a doubly Cr(CO)3-complexed diphenylbutadiyne 7 in excellent yield.
    Additional Material: 2 Ill.
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    URL: http://dx.doi.org/10.1002/cber.19961290604
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    Preparation, Properties, and Reactions of Metal-Containing Heterocycles, XCIIIPart XCII: E. Lindner, P. Fisahn, R. Fawzi, M. Steimann, Chem. Ber. 1996, 129, 191-199.. Diosma[5.n.5.n]ortho-, -meta-, and -paracyclophanes (n = 0-2)Dedicated to Professor Erwin Weiss on the occasion of his 70th birthday. (1996)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 129 (1996), S. 639-645 
    Details
    ISSN: 0009-2940
    Keywords: Metallacyclophanes ; Osmium complexes ; Iron complexes ; Oxocyclophanes ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The reaction of the ortho-, meta-, and para-bis(triflates) [(F3CSO2OCH2CH2C6H4)2(CH2)n] with n = 0 (ortho: 1a), n = 0, 1 (meta: 1b, d), and n = 0-2 (para: 1c, e, g) with [Os(CO)4]2- results in the formation of the diosma[5.n.5.n]-ortho-, -meta-, and -paracyclophanes with n = 0 (ortho: 2a), n = 0, 1 (meta: 2b, d), and n = 0-2 (para: 2c, e, g). On reaction of the bis(triflates) 1a, b with the dianionic [Fe(CO)4]2- the corresponding ferracyclophanes are formed only in situ. Carbon monoxide insertion into the Fe-C s̰ bonds of the ferracycles affords the ketones 6a, b. The structures of 2a and 2e were investigated by X-ray structural analysis. Compounds 2a and 2e crystallize in the space group P21/c with Z = 8 and P1 with Z = 2, respectively.
    Additional Material: 4 Ill.
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    URL: http://dx.doi.org/10.1002/cber.19961290608
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    Hexacoordinated Group-14 Elements with Phosphorus Donor Ligands: Syntheses and Structures of Cl2E[C(PMe2)2(SiMe3)]2 (E = Si, Ge, Sn) (1996)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 129 (1996), S. 671-676 
    Details
    ISSN: 0009-2940
    Keywords: Hexacoordination ; Silicon ; Germanium ; Tin ; Phosphinomethanide Ligands ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The group-14 tetrahalides ECl4 (E = Si, Ge, Sn) react with two equivalents of Li[C(PMe2)2(SiMe3)] to give the trans-hexacoordinated complexes Cl2E[C(PMe2)2(SiMe3)]2, which were characterized spectroscopically and by structure determinations in the solid state. The complexes were found to crystallize with or without tetrahydrofuran (THF) molecules, depending on the presence or absence of this solvent. In the case of the silicon complex, the structures of both crystal forms were determined, showing slightly different molecular structures of the complexes in the solid state. Without cocrystallized THF, Cl2Si[C(PMe2)2(SiMe3)]2 has no crystallographically imposed molecular symmetry, while in the presence of THF its crystallographic symmetry is C2h (2/m). The tin and germanium complexes were crystallized either with and without THF molecules, respectively, their crystal structures being isotypic with the respective ones of the silicon complex. In all cases, small amounts of the cis-hexacoordinated isomers were also observed in solution, but only in the case of the silicon complex, it was isolated in pure form. It rearranges to the trans isomer at ambient temperature. trans-Cl2Si[C(PMe2)3]3, trans-Cl2Si[C(PPh2)2(SiMe3)]2 and cis-Me2-Si[C(PMe2)2(SiMe3)]2 were likewise obtained.
    Additional Material: 5 Ill.
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    URL: http://dx.doi.org/10.1002/cber.19961290613
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    New β-Amino Alcohols as Chiral Ligands for the Catalytic Enantioselective Reduction of Prochiral Ketones and the Nucleophilic Addition of Diethylzinc to BenzaldehydeDedicated to Dr. Werner Schwarze. (1996)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 129 (1996), S. 691-695 
    Details
    ISSN: 0009-2940
    Keywords: β-Amino alcohols ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: New optically active β-amino alcohols, derived from various acyclic and cyclic amino acids with alkyl groups on the carbinol carbon atom, were used in the enantioselective reduction of prochiral ketones. The attachment of alkyl groups to the nitrogen atom of the catalyst (R)-1b was shown to influence favorably the enantioselectivity of the addition of diethylzinc to benzaldehyde. In both cases the resulting secondary alcohols were obtained in moderate to high optical yields.
    Additional Material: 2 Tab.
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    URL: http://dx.doi.org/10.1002/cber.19961290616
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    Masthead (1996)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 129 (1996) 
    Details
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19961290701
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    Conformation of tripod Metal Templates in CH3C(CH2PPh2)3MLn (n = 2, 3): Neural Networks in Conformational AnalysisDedicated to E. Weiss on the occasion of his 70th birthday. (1996)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 129 (1996), S. 745-757 
    Details
    ISSN: 0009-2940
    Keywords: Conformational analysis ; Triphos ligands ; Neural networks ; Factor analysis ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The conformational space spanned by tripod metal templates CH3C(CH2Ph2)3M is analysed on the basis of the solid-state structures of 82 tripodCo templates in compounds tripodCoL2 and tripodCoL3. Systematic analysis, including the techniques of conformational space group scatter graphs, principal-component analysis, and partial least squares, reveals a series of basic regularities: The torsion of the phenyl groups is strongly linked to the torsional skew of the bicyclooctane-type framework of the chelate cage. For one sense of this skew there are two classes of low-energy conformation that differ by the helicity of the phenyl arrangement and by the degree of torsional skew in the chelate backbone. From the scatter graphs it is evident that a change in helicity may occur by one- or by two-ring flip mechanisms. The basic regularities found by the above methods are also evident from the analysis of the same data by a neural network approach. The fact that these regularities are found for tripodCoL2 and tripodCoL3, irrespective of the widely different coligands L and crystal environments, means that the conformation of the tripod metal templates is governed by the forces acting within them and not so much by the forces imposed on them by their individual chemical or crystal environment. It is shown that the classifications, although derived from a data basis only containing Co compounds, are characteristic for tripod metal templates irrespective of the specific metal involved.
    Additional Material: 11 Ill.
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    Structural and Electrochemical Comparison of NiII in an N2S2 Plane with Two, One and No Axial Ligands: Isolation and Characterization of a Five-Coordinate Nickel(II) Complex (1996)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 129 (1996), S. 779-784 
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    ISSN: 0009-2940
    Keywords: Thioether, benzyl ; Mercapto amines ; Nickel complexes ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Addition of two equivalents of benzyl bromide to [N,N′-bis(2-mercaptoethyl)-1,5-diazacyclooctane]nickel(II) (Ni-1) produced the green dibenzyl dithioether complex [Ni-1-Bzl2Br2] structurally characterized by X-ray crystallography as a six-coordinate octahedral complex in a monoclinic crystal system and the P21/c space group. Benzylation of the methyl thioether/thiolate [(Ni-1-Me)+I- yielded the mixed benzyl/methyl dithioether [(Ni-1-BzlMe)Br]I, structurally characterized by X-ray crystallography as a five-coordinate square pyramidal nickel(II) complex with a Ni-Br distance of 2.451 Å. The complex crystallizes in the orthorhombic Cmca space group. The latter is the first nickel(II) pentacoordinate complex isolated for the N,N′-bis(2-mercaptoethyl)-1,5-diazacyclooctane (daco) ligand. Structural comparison of these two complexes with the square-planar dimethyl compound [Ni-1-Me2]I2 found an expansion of the N2S2 plane upon addition of axial ligands. The five-coordinate nickel complex showed a displacement of the Ni ion from the N2S2 plane by 0.43 Å toward the axial bromide ligand, a common observation of pentacoordinate complexes of this ligand with metals such as Zn and Fe. Electrochemical studies as well as the X-ray crystal structures for complex [Ni-1-Bzl2Br2] and [(Ni-1-BzlMe)Br]I are presented and discussed in detail.
    Additional Material: 5 Ill.
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    URL: http://dx.doi.org/10.1002/cber.19961290708
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    Self-Assembly of a Triple-Stranded meso-Helicate from Two Iron(II) Ions and Three [CH2]3-Bridged Bis(2,2′-bipyridine) Ligands (1996)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 129 (1996), S. 829-832 
    Details
    ISSN: 0009-2940
    Keywords: Self-assembly ; meso-Helicate ; Binuclear coordination compounds ; 2,2′-Bipyridines ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: 1,3-Bis(5′-methyl-2,2′-bipyrid-5-yl)propane (3) can be synthesized by a two-step procedure starting from 3-picoline (1). In a spontaneous self-assembly process 3 forms the binuclear triple-stranded meso-helicate [(3)3Fe2][PF6]4 on addition of iron(II) salts. The (Λ,Δ) structure can be shown by symmetry considerations based on NMR spectroscopy and is due to the conformational restrictions of the [CH2]3 spacer.
    Additional Material: 2 Ill.
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    URL: http://dx.doi.org/10.1002/cber.19961290714
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    Masthead (1996)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 129 (1996) 
    Details
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19961290801
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    Zinc Complexes of Amino Acids and Peptides, 7Part 6: Ref.[1].. Solution Behavior and Zinc Complexation of Dipeptides Made up Solely from Histidine and CysteineDedicated to Professor Max Herberhold on the occasion of his 60th birthday. (1996)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 129 (1996), S. 887-895 
    Details
    ISSN: 0009-2940
    Keywords: Dipeptides ; Histidine ; Cysteine ; Zinc complexes, solution studies of ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The eight possible types of dipeptides made up from histidine and cysteine, namely the unprotected ones H-His-Cys- OH (1) and H-Cys-His-OH (2), the N-protected ones Ac-His-Cys-OH (3) and Ac-Cys-His-OH (4), the C-protected ones H-His-Cys-OEt (5) and H-Cys-His-NH2 (6), and the fully protected ones Ac-His-Cys-OEt (7) and Ac-Cys-His-OEt (8) were prepared analytically pure. Their acid-base behavior and zinc complexation in solution were studied potentiometrically. In all cases 1:1 (zinc:peptide) complexes are the dominant species near neutral pH. 1:2 complexes could only be detected for 4, 6, 7, and 8, and precipitations occurred in basic media. From equimolar mixtures of the peptides and zinc salts (chloride, iodide, perchlorate) solid complexes were obtained upon addition of a base. They always contain coordinating anions (chloride, iodide, or trifluoroacetate which was introduced with the peptide). They have the composition LZnX for L = 5-8 and L4Zn5X2 for L = 1-4. It is proposed that all complex species observed contain tetrahedral zinc, that they are monomers in dilute solution and thiolate-bridged oligomers in the solid state, and that the peptides as a rule occupy at least three coordination sites.
    Additional Material: 4 Ill.
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    The Unexpected Formation of a Tetradentate Tripyrrolic Complex of Nickel(II) (1996)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 129 (1996), S. 1195-1198 
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    ISSN: 0009-2940
    Keywords: Pyrrolic nickel(II) complexes ; Imine hydrolysis ; Template effect ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: (2-Pyrrolylmethane)(2-pyrrolylmethyl)imine (2) and an equimolar amount of 2-formylpyrrole give, in the presence of nickel(II) in hot methanol, the novel tripyrrolic nickel(II) complex [SP-4]-[(2-dipyrrinato-k2N,N′-methyl)(2-pyrrolylmethenato- kN′′)imine-kN′′′]nickel(II) (4). This planar complex has been characterized by X-ray crystallography, a mechanism for its formation is proposed and its mass spectral behavior is discussed.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19961291009
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    The Crystal Structure of Bi8(AlCl4)2 and the Crystal Structure, Conductivity, and Theoretical Band Structure of Bi6Cl7 and Related Subvalent Bismuth Halides (1996)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 129 (1996), S. 1219-1226 
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    ISSN: 0009-2940
    Keywords: Bismuth subhalides ; Band structure and electrical conductivity of Bi6Cl7 ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The methods of preparation for Bi8(AlCl4)2 and Bi6Cl7 have been improved and the single crystal structures for these cluster compounds re-investigated and re-interpreted. In addition, conductivity measurements and band structure calculations using the tight-binding approximation have been performed on Bi6Cl7 and related subvalent bismuth halides. - Bi8(AlCl4)2 consists of isolated AlCl4- anions and rather undistored square-antiprismatic Bi82+ clusters with an average Bi-Bi distance of 3.10 Å. Relatively short intercluster Bi-Bi contacts of 3.90 Å suggest weak bonding interactions between the Bi82+ units. In contrast, the structure determination of Bi6Cl7 implies that this structure should be regarded as being composed of discrete Bi95+ clusters and a polymeric BiIII-Cl anionic lattice including infinite, distorted α1[Bi2Cl24+] chains. According to the experimental and theoretical results, the Bi6X7 (X = Cl, Br) family of subvalent bismuth halide compounds are anisotropic semiconductors along the crystallographic c axis. The conductivity is mediated by the onedimensional α1[Bi2Cl24+] chains. These are interconnected with the Bi95+ clusters, which are acting as electron reservoirs. The related BiX (X = Br, I) family of subvalent bismuth halides are shown to be anisotropic semiconductors in the crystallographic b direction.
    Additional Material: 8 Ill.
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    URL: http://dx.doi.org/10.1002/cber.19961291013
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    Stable Carbonyl- and Thiocarbonylrhodium(I) Complexes Containing s̰-Bonded Phenyl and Vinyl Groups as Ligands (1996)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 129 (1996), S. 29-31 
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    ISSN: 0009-2940
    Keywords: Rhodium(I) complexes with phenyl and vinyl ligands ; Carbonylrhodium(I) complexes ; Thiocarbonylrhodium(I) complexes ; Rhodium(I) complex with CS2 as ligand ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The phenyl- and vinylrhodium(I) complexes trans-[Rh(R)(CO)(PiPr3)2] (2, 3) were prepared from the chloro derivative 1 and Grignard reagents. The corresponding thiocar-bonyl compound trans-[Rh(CH=CH2)(CS)(PiPr3)2] (7) was obtained similarly from trans, -[RhCl(CS)(PiPr3)2] (6) and CH2=CHMgBr. The preparation of 6 occurred via trans- [RhCl(η2-S=C=S)(PiPr3)2] (5) as intermediate. The carbonyl complexes 2 and 3 are quite inert in the presence of CO and do not react by migratory insertion to give acylrhodium derivatives.
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    P8 and P12 as Complex LigandsDedicated to Prof. Henri Brunner on the occasion of his 60th birthday. (1996)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 129 (1996), S. 53-58 
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    ISSN: 0009-2940
    Keywords: P8 ligand ; P12 ligand ; P5-P3, P5-P7 building blocks ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The thermal and/or photochemical reaction of [Cp‴Co(CO)2] (1), Cp‴ = 1,2,4-tBu3C5H2, with white phosphorus, P4, gives besides [(Cp‴Co)2 (P2)2] (2) the trinuclear complexes [(Cp‴Co)3P8] (3) and [(Cp‴Co)3P12] (4), the Pn ligands of which form P5-P3 and P5-P7 skeletons, structural motifs, which formally can be derived from Hittorf's phosphorus. The X-ray crystal structure analysis of 3 confirmed its P5-P3 framework.
    Additional Material: 3 Ill.
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    URL: http://dx.doi.org/10.1002/cber.19961290112
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    Synthesis and Structure of Bis(2,4-di-tert-butyl-1,3-cyclopentadien-1-yl)-disulfane, S2(tBu2C5H3)2, and Bis[2,4-di-tert-butyl-5-(trimethylsilyl)-1,3-cyclopentadien-1-yl]disulfane, S2 [tBu2(Me3Si)C5H2]2 (1996)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 129 (1996), S. 69-71 
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    ISSN: 0009-2940
    Keywords: Disulfanes ; Cyclopentadienyl ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Reaction of 1,3-di-tert-butylcyclopentadienyllithium and 1,3-di-tert-butyl-4-(trimethylsilyl)cyclopentadienyllithium with S2Cl2 gives bis(2,4-di-tert-butyl-1,3-cyclopentadien-1-yl)di-sulfane (1) and bis[2,4-di-tert-butyl-5-(trimethylsilyl)-1,3-cyclopentadien-1-yl) disulfane (2), respectively. The structure of 2 was determined by single-crystal X-ray diffraction. Compounds 1 and 2 are the first biscyclopentadienylchalcogens with the chalcogen in vinylic position.
    Additional Material: 1 Ill.
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    Chirale Tripodliganden mit Phosphor- und Schwefeldonoren. Synthese und Komplexchemie (1996)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 129 (1996), S. 97-108 
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    ISSN: 0009-2940
    Keywords: Tripod ligands ; Chiral ; Oligodentate P,S-ligands ; Nickel-sulfur Compounds ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Chiral Tripod Ligands with Phosphorus and Sulfur Donors. Synthesis and Complex ChemistryNeopentane based tripod ligands CH3C(CH2X)(CH2Y)-(CH2Z) with mixed donor groups X,Y,Z (PR2, SR, SH) are accessible via two different strategies. The functionalized thietane CH3(CH2X)ČH2SCH2 allows stepwise introduction of P or S donors by substitution of the mesylate function and subsequent nucleophilic cleavage of the thietane ring. Tripod ligands 5 [CH3C(CH2X)(CH2Y)(CH2Z)] with up to three different donor groups (X = SH; Y = PPh2; Z = P(4-Tol)2, SCH2Ph, PPh2) are thus available. As an alternative the neopentane derivatives 8 [CH3C(CH2X)(CH2Y)(CH2Cl)] which are easily assessible from CH3C(CH2OSO2Me)(CH2Br)-(CH2Cl) (7) by stepwise substitution with phosphides LiPAr2 (Ar = aryl) may be transformed to 9 [CH3C(CH2X)(CH2Y)(CH2SBzl)]. Under controlled conditions the S - benzyl bond of 9 is cleaved reductively without concomitant cleavage of P - Ar bonds. Ligand 5a [CH3C(CH2PPh2)2(CH2SH)] reacts with Ni(BF4)2 · 6 H2O to yield the dinuclear species [(CH3C(CH2PPh2)2-(CH2S)Ni)2]2+ (10). The two ligands are bonded in an equivalent way with each of the two nickel centers interacting with one of the two phosphane functions of the ligand; the thiolate functions form μ2-SR bridges between the two nickel atoms. The SCH2 group at the four-membered S2Ni2 ring are in mutual cis position with the four-membered ring bent along the sulfur-sulfur axis by 70°. The internal strain in 10 is analyzed by comparing its structure with the ones of [(CH3C(CH2-PPh2)3NiSPh)2]2+ (11) and [(CH3C(CH2OH)(CH2PPh2)2-NiOH)2]2+ (12).
    Additional Material: 4 Ill.
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    URL: http://dx.doi.org/10.1002/cber.19961290119
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    The First Selective Cage Redistribution Reaction of P4O6Dedicated to Professor Rolf Appel on the occasion of his 75th birthday. (1996)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 129 (1996), S. 121-124 
    Details
    ISSN: 0009-2940
    Keywords: N-Organyl tetraphosphorus hexaoxide ; Cage redistribution ; Nitrene insertion ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Reaction of tetraphosphorus hexaoxide with organic azides leads selectively to the cage redistribution products 1 P4O6NPh, 2 P4O6NC2H4Ph, 3 P4O6NSO2CH3, 4 P4O6NC6H13, and 5 P4O6NCO2C2H5 by nitrene insertion. The molecular structure consists of an adamantane-like P4O5N cage with a terminally bound oxygen atom. The P4O5N cagelike structure is confirmed by 31P NMR spectroscopy and X-ray structure analysis. The P4O5N cages of the P4O6NR molecules possess a significant geometrical distortion.
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    URL: http://dx.doi.org/10.1002/cber.19961290202
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  • 146
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    Reactions of the Alkylindium(I) Compound In4[C(SiMe3)3]4 with Sulfur and Tellurium: Syntheses of In4S4[C(SiMe3)3]4 and In4Te4[C(SiMe3)3]4 with Indium Chalcogen Heterocubane Structures (1996)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 129 (1996), S. 143-146 
    Details
    ISSN: 0009-2940
    Keywords: Tetraindane(4) ; Indium(I) ; Sulfur ; Tellurium ; Heterocubane ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Tetrahedro-Tetrakis[tris(trimethylsilyl)methyl]tetraindane(4) (1) with a tetrahedral In4 molecular center reacts with an excess of elemental sulfur or tellurium in boiling n-hexane to give in an almost quantitative yield the appropriate In4S4 (2) or In4Te4 derivatives (3). Crystal structure determinations revealed distorted In4X4 (X = S, Te) heterocubane molecular centers for both compounds.
    Additional Material: 2 Ill.
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    URL: http://dx.doi.org/10.1002/cber.19961290206
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  • 147
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    On the Effect of 1,2-Disubstitution with Me3M (M = Si, Ge, Sn) Groups upon the Electronic Structure of 3,3-Dimethylcyclopropene (1996)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 129 (1996), S. 169-174 
    Details
    ISSN: 0009-2940
    Keywords: Electronic structure ; Cyclopropenes, 3,3-dimethyl- ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: He(I) PE spectra of a series of 3,3-dimethylcyclopropenes bearing Me3Si (1), Me3Ge (2), and Me3Sn (3) groups in the 1- and 2-positions, as well as the He(II) PE spectra of 1 and 3 were recorded. The changes in the lowest energy ionizations along the series are interpreted in terms of inductive and hy-perconjugative interactions. The new compounds were prepared by reaction of lithiated 3,3-dimethylcyclopropene with the corresponding trimethylmetal chlorides.
    Additional Material: 3 Ill.
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    URL: http://dx.doi.org/10.1002/cber.19961290210
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    Transition Metal-Substituted Arsaalkenes, II. Synthesis, Structure and Reactivity of the Arsaalkenes RAs=C(NMe2)2 [R = Me3Si, (η5-C5Me5)(CO)2Fe] and the 1,2-Dihydroarsete (η5-C5Me5)(CO)2-Fe (1996)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 129 (1996), S. 223-226 
    Details
    ISSN: 0009-2940
    Keywords: Arsaalkenes ; Carbonyliron complexes ; Arsete, 1,2-dihydro- ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Reaction of equimolar amounts of thiuronium salt [(Me2N)2C-SMe]I (1, with LiAs(SiMe3)2 · 2 THF (2) afforded arsaalkene Me3SiAs=C(NMe2)2 (3). Combination of 3 with (η5-C5Me5)(CO)2 FeBr led to the formation of (η5-C5Me5)(CO)2-FeAs=C(NMe2)2 (4). Reaction of the latter with dimethyl fumarate gave the 1,2-dihydroarsete (η5-C5Me5)(CO)2-Fe (6). Compounds 3, 4, and 6 were characterized by means of spectroscopy (IR, 1H, 13C{1H}, 29Si{1H} NMR and mass spectrometry). The molecular structures of 4 and 6 were determined by X-ray diffraction analysis.
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    URL: http://dx.doi.org/10.1002/cber.19961290217
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  • 149
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    Nickel Hemiporphyrazines as Bisdienes and Bisdienophiles: Synthesis and Characterization (1996)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 129 (1996), S. 237-242 
    Details
    ISSN: 0009-2940
    Keywords: Hemiporphyrazines ; Macrocyclic bisdienes and bisdienophiles ; Nickel complexes ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The bisdienophilic (hemiporphyrazinato)nickel complexes 1a-d bearing various alkoxy groups were synthesized from diiminoisoindoles 9a-d, diaminopyridines 10a, d, and nickel acetate. Reaction of 1a-d with an excess of pentaene 3 delivered the macrocyclic bisdienes 2a-d. The hemiporphyrezines were characterized by 1H- and 13C-NMR spectroscopy. The NMR spectra of the 1,6,16,21-tetrabutoxy-substituted compounds 1b and 2b are discussed with respect to the presence of syn/anti isomers.
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    URL: http://dx.doi.org/10.1002/cber.19961290220
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    2-(2,4-Di-tert-butylphenyl)-1,1-bis(trimethylsilyl)silene and 2-(2,4,6-Tri-tert-butylphenyl)-1,1-bis(trimethylsilyl)silene - Two New Sterically Protected but Still Unstable Silaethenes (1996)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 129 (1996), S. 15-20 
    Details
    ISSN: 0009-2940
    Keywords: Silenes ; Silene dimerization ; 1,2-Disilacyclobutanes ; 2,3-Disilanaphthalene, tetrahydro- ; 2-Silanaphthalene, tetrahydro- ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: (2,4-Di-tert-butylphenyl)tris(trimethylsilyl)silylmethanol (1a), prepared by the reaction of tris(trimethylsilyl)silylmagnesium bromide with 2,4-di-tert-butylbenzaldehyde, was deproto-nated by treatment with methyllithium in ether at -78°C to give the transient 2-(2,4-di-tert-butylphenyl)-1,1-bis(trimeth-ylsilyl)silene (3a), which dimerizes in a head-to-head fashion with the formation of (E)-/(Z)-3,4-bis(2,4-di-tert-butylphenyl)-1,1,2,2-tetrakis(trimethylsilyl)-1,2-disilacyclobutane (5). Besides 5 an unstable compound 4 was obtained, which was preliminarly assigned as 5,7-di-tert-butyl-1-(2,4-di-tert-bu-tylphenyl) -1,2,3,8a-tetrahydro-2,2,3,3-tetrakis(trimeth-ylsilyl)-1,2-disilanaphthalene (4), the formal [2 + 4] cyclodimer of 3a. Compound 4 gradually decomposes to give (E)-/(Z)-5, and is considered to be the kinetically preferred dimer of 3a, which is converted into the thermodynamically stable 5. 2,4,6-Tri-tert-butylbenzaldehyde reacts with tris(tri-methylsilyl)silyllithium resulting in the formation of 6,8-di-tert-butyl-1,2,3,4-tetrahydro-4,4-dimethyl-2,2- bis(trimethylsilyl)-2-silanaphthalene (6). Compound 6 is the product of the insertion of the Si=C bond into the C-H bond of an o-tert-butyl group of the intermediate 2-(2,4,6-tri-tert-butylphenyl)-1,1-bis(trimethylsilyl)silene (3b), which despite extreme steric shielding proved to be still unstable. For compounds (Z)-5 and 6 the results of the X-ray analyses are given.
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    URL: http://dx.doi.org/10.1002/cber.19961290105
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    Charge-Transfer Complexes of Metal Dithiolenes, XXIIPart XXI: Ref.. Bis(maleonitriledithiolato)oxomolybdate(IV) - Bipyridinium Ion PairsDedicated to Professor Herrmann Rau on the occasion of his 60th birthday. (1996)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 129 (1996), S. 33-37 
    Details
    ISSN: 0009-2940
    Keywords: Oxomolybdenum dithiolenes ; Viologens ; Ion pair charge-transfer ; Hydrogen bonds ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The oxomolybdenum complex (NBu4)2[MoO(mnt)2] (mnt2- = maleonitriledithiolate) 2 was characterized by X-ray structural analysis. By metathetic reaction with bipyridinium salts AX2 ion pair charge-transfer complexes of composition {A2+[MoO(mnt)2]2-} were isolated. Although a plot of the energy of the ion pair charge-transfer band vs. the driving force of electron transfer from the dianion to the dication afforded a straight line, the slope of 0.45 suggests significant deviations from the Hush-Marcus model. When bis(2-hy-droxyethyl)viologen is the acceptor, in addition to the supra-molecular charge-transfer interaction, hydrogen bridges are introduced between the two components as indicated by IR and X-ray diffraction analysis.
    Additional Material: 5 Ill.
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    URL: http://dx.doi.org/10.1002/cber.19961290109
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    Synthesis and Structure of Tris(trialkylstannyl)- and Tris(dialkylhalostannyl)amines; Stabilization of the Sn3N Skeleton by Intramolecular Sn-X-Sn Bridges (1996)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 129 (1996), S. 175-189 
    Details
    ISSN: 0009-2940
    Keywords: Tristannylamines ; Tris(trialkylstannyl)amines ; Tris(dialkylhalostannyl)amines ; Sn-N Bond cleavage ; Sn-X-Sn Intramolecular bridges ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Tris(triorganylstannyl)amines (R2R'Sn)3N (1, 2) with substituents R = R' = Me, Bu or R = Me and R' = iPr, tBu are obtained by metathesis from R2R'SnX and NaNH2 in liquid ammonia or by transamination of R3SnNMe2 with NH3. Tris(diorga-nylhalostannyl)amines (R2XSn)3N (3) are synthesized by stannazane cleavage of (Me3Sn)3N (1) with R2SnX2. Information from multinuclear magnetic resonance spectra ascertain the planarity of the Sn3N skeleton of type 2 and 3, as well as the relationship between the coupling constants 1J(119Sn15N) and 2J(119Sn117Sn) and the Sn-N bond length as determined by the X-ray structure analysis of 1, 3b and 3r. Compound 3b shows an almost undistorted D3h symmetry with a planar Br3Sn3N skeleton and SnN bond lengths of 1.99 Å, which beside those of 3a are the shortest found so far. According to MNDO approximate and ab initio calculations π interactions between the lone electron pair at the N atom and empty orbitals at the Sn atoms can be excluded. Therefore, the tristan-nylamines discussed here have a trigonal planar nitrogen center with its lone electron pair in a p-type orbital. Further characteristic features of the molecular structures of typ 3 compounds are the intramolecular Sn-X-Sn bridges (X = Cl, Br, I) found in the solid state as well as in solution. The molecular geometries of the tristannylamines are supported by MS fragmentation patterns as well as by infrared and Raman spectra.
    Additional Material: 4 Ill.
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    URL: http://dx.doi.org/10.1002/cber.19961290211
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    Synthesis and Structure of Metal-Functionalized Phosphaarsiranes (1996)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 129 (1996), S. 219-222 
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    ISSN: 0009-2940
    Keywords: Arsaphosphapropene ; Phosphaarsiranes ; Carbonylchromium complexes ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Reaction of (η5-C5Me5)(CO)2FeAs(SiMe3)2 (1) with equimolar amounts of (bis(trimethylsilyl)methylene]chlorophosphane afforded the 1-metallo-1-arsa-2-phosphapropene (η5-C5-Me5)(CO)2FeAs(SiMe3)P=C(SiMe3)2 (2) in addition to a few crystals of dimetallophosphaarsirane (η5-C5Me5)(CO)2Fe- AsC(SiMe3)2PFe(CO)2(η5-C5Me5) (3). Treatment of 2 with an excess of [(Z)-cyclooctene]Cr(CO)5 and subsequent chromatography furnished the phosphaarsirane-[Cr(CO)5] adduct (η5-C5Me5)(CO)2Fe-ηAsC(SiMe3)2PH[Cr(CO)5] (5). The molecular structures of 3 and 5 were established by single-crystal X-ray structure analyses.
    Additional Material: 2 Ill.
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    URL: http://dx.doi.org/10.1002/cber.19961290216
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    Masthead (1996)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 129 (1996) 
    Details
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19961290201
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    A New Reagent for Nucleophilic Aminomethylation: Doubly Lithiated Bis(dimethylamino)methane and Its Use for the Synthesis of Si,N-Heterocycles (1996)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 129 (1996), S. 483-484 
    Details
    ISSN: 0009-2940
    Keywords: Aminals ; Nucleophilic aminomethylation ; Si,N-Heterocycles ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The aminal Me2NCH2NMe2 is doubly metalated by LitBu to give LiCH2N(Me)CH2N(Me)CH2Li, which reacts with chlorosilanes to afford the respective silylated species, including the six-membered heterocycle Me2SiCH2N(Me)CH2N(Me)-CH2 and the spiroheterocycle Si[CH2N(Me)CH2N(Me)CH2]2.
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    URL: http://dx.doi.org/10.1002/cber.19961290502
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    Ethyloboration of Selenium Dioxide and Selenium Bis(tert-butylimide) - Molecular Structure of an Organo-Substituted Eight-Membered [-BOSeO-]2 Heterocycle (1996)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 129 (1996), S. 503-507 
    Details
    ISSN: 0009-2940
    Keywords: Selenium dioxide, 1,2-ethyloboration ; Selenium diimide, 1,2-ethyloboration ; Seleninic acid, ethane- ; Transborylation, OBEt2, O-9-BBN ; Ethene, elimination ; Amino(diethyl)boranes ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Both selenium dioxide (1) and selenium bis(tert-butylimide) (2) react with triethylborane (A) by 1,2-ethyloboration. In the case of 1, ethane, ethene, diethylselane (4a), tetraethyldiboroxane (Et2B)2O (B), triethylboroxine (EtBO)3 (D) and a cyclic compound [-Et2BOSe(Et)O-]2 (52) are formed after heating to 65°C. Compound 52 is also formed when 1 reacts with B. Treatment of selenous acid (3) with A or, preferentially for synthetic purposes, with B provides further routes to 52. The reaction of the diimide 2 with A starts already below -50°C: a cyclic ethaneselenic acid derivative 6, Et2BN(tBu)-Se(Et)NtBu, is formed, and 6 starts to decompose at -50°C by elimination of ethene to give finally (tert-butylamino)diethylborane (8), bis(diethylboryl)-tert-butylamine (9), and Et2Se (4a). Transborylation of 52 with (9-BBN)2O (C) affords [-(9-BBN)OSe(Et)O-]2 (102), which crystallizes in the monoclinic space group P21/n with the lattice constants (118 K) a = 667.1(1), b = 1282.5(1), c = 1289.1(1) pm and β = 93.06(1)°. All reactions were monitored by 11B- and 77Se-NMR spectroscopy. Furthermore, the reactions of 1 with A and B and the transborylations were studied by 17O-NMR spectroscopy using the 17O-enriched compounds 1(17O), B(17O), C(17O), and D(17O).
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    Preparation, Properties, and Reactions of Metal-Containing Heterocycles, XCIIPart XCI: Ref.. Steric and Solvent Effects of the Different Reaction Patterns of Activated Alkynes with DiphosphamanganacyclopropanesDedicated to Professor Herbert W. Roesky on the occasion of his 60th birthday. (1996)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 129 (1996), S. 191-199 
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    ISSN: 0009-2940
    Keywords: Bicyclic manganese compounds ; P-P bonds ; Activated alkynes ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The product pattern of the reaction of the alkynes ZC≡CZ (4-11) [Z = CO2R: R = Me (4), Et (5), nPr (6), iPr (7), nBu (8), nPent (9), neo-Pent (10), cyc-Hex (11)] with the diphospha-manganacyclopropanes (1-3) depends on the polarity of the employed solvent. Whereas in n-hexane the diphosphamanganabicyclo[3.3.0]octadienones 12a-q, the diphosphamanganacyclopentenes 13a-h, and the triphosphamanganabicyclo[3.2.0]heptenones 14a-h are formed, in THF only the five-membered heterocycles 13 occur. Compound 14d is easily oxidized to the corresponding oxide 15d. According to X-ray structural analyses, both 14d and 15d crystallize in the space group P&1macr;. The Lewis basic properties of the phosphorus atom P2 in the heterocycle 1 were corroborated by reaction of 1 with THFCr(CO)5 leading to the adduct (16). Quantitative 31P{1H}-NMR investigations in CDCl3 enable the determination of the product ratio 13/12 as a function of the steric encumbrance of the ester substituents. An increase of the steric hindrance leads to the preferential formation of the mo-nocyclic compounds 13. If the steric demand at the phosphorus atom P2 is released, only the bicyclic compounds 12i-q are formed.
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    URL: http://dx.doi.org/10.1002/cber.19961290212
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    Chelate-Controlled Additions of Titanium and Lithium Enolates to Chiral β-Formyl Esters - Diastereofacial and Simple Diastereoselectivity (1996)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 129 (1996), S. 227-232 
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    ISSN: 0009-2940
    Keywords: β-Formyl esters ; Titanium enolates ; Lithium enolates ; Silyl enol ethers ; Chelate control ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The aldol-type additions of metal enolates 2-Met derived from pinacolone to the chiral β-formyl carboxylate 1a were optimized. The highest trans:cis ratio (86:14) of the products 3 was obtained when the trichlorotitanium enolate 2-TiCl3 was combined with 1a precomplexed with one equivalent of TiCl4. The lithium enolate 2-Li is rather unselective. The simple diastereoselectivity of prochiral enolates 4-Met was first examined with achiral β-formyl carboxylates 1b and 1c. Appropriate reagents made products with high anti or with high syn selectivity available when the unbranched aldehyde 1b was the electrophile. In contrast, the sterically more hindered aldehyde 1c provided syn products with all enolates 4-Met employed. Finally, chiral aldehyde 1a was combined with prochiral enolates 4-Met. Conditions could be found which furnished either the trans/anti or the trans/syn product 7 with good selectivity. The results are discussed and compared with reactions of related metal enolates with aldehydes capable of chelate formation.
    Additional Material: 2 Tab.
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    URL: http://dx.doi.org/10.1002/cber.19961290218
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    Tripod-Cobalt-Formiat-Komplexe in den Oxidationsstufen +II und +I (1996)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 129 (1996), S. 243-245 
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    ISSN: 0009-2940
    Keywords: Tripodal ligands ; Cobalt complexes ; Formate complexes ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Tripod-Cobalt Formate Complexes of Oxidation States +II and +IThe syntheses of the (tripod)cobalt formate complexes [(tri-pod)Co(O2CH)]n+ (1/1+; n = 0, 1; tripod = CH3C(CH2PPh2)3) are presented. The structures are established by X-ray analyses as well as the usual analytical techniques.
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    URL: http://dx.doi.org/10.1002/cber.19961290221
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    Reactions of Complex Ligands, LXXPart LXIX: Ref.[1].. An Intramolecular Alkyne Insertion/Carbonylation/Cyclization Sequence of Chromium Aminocarbene Complexes: A Novel Access to Indole and Indenoindole Skeletons (1996)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 129 (1996), S. 623-631 
    Details
    ISSN: 0009-2940
    Keywords: Carbene complexes ; Chromium complexes ; Benzannulation ; Cyclopentannulation ; Benzocarbazoles ; Indenoindoles ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: 2-Alkynylanilinocarbene chromium complexes 1-7 bearing a rigid arene C2 spacer between the aminocarbene and alkyne units were prepared from pentacarbonyl(aroyl)chromates(-I), acetyl bromide, and 2-alkynylanilines. They undergo intramolecular cyclization the course of which depends on the substitution pattern at the alkyne terminus. A tandem alkyne insertion into the metal-carbene bond/carbonylation sequence affords Cr(CO)3-coordinated 3-indolylketenes 8, 9, 12-14 by using a bulky substituent; the rate of the reaction increases with N-alkylation. Less bulky n-alkynylanilinocarbene complexes 4, 5 exhibit two competing carbene annulation sequences: Benzannulation leads to benzo[a]carbazoles 15, 16, whereas cyclopentannulation without prior carbonylation furnishes indeno[1,2-b]indoles 17, 18.
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    The Reaction of As4Sn (n = 3, 4) and As2S3 with (C5Me4R)2Co2(CO)2 (R = Me, Et): Fragmentation and Reassembling of Main-Group Ligands by Organometallic Complexes (1996)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 129 (1996), S. 657-662 
    Details
    ISSN: 0009-2940
    Keywords: Cobalt complexes ; Arsenic sulfides ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The reaction of Cp2#Co2(CO)2 1 (Cp# = Cp* or Cpx; Cp* = C5Me5: a; Cpx = C5Me4Et: b) with equimolar amounts of As4Sn (n = 3, 4) and As2S3 was investigated at different temperatures. The formation of Cp2#Co2(CO)As2S2 3, Cp2#Co2As2S3 4, Cp3#Co3As2S4 5, and Cp3#Co3As4S2 6 was observed in ratios depending on the reaction conditions. Starting from As4S4 or As4S3 and 1b insertion of a CpxCo(CO) fragment into one of the As-As bonds of the cages was achieved in low yields leading to CpxCo(CO)As4S4 2b and CpxCo(CO)As4S3 8, respectively. Structures were studied by means of IR and 1H-NMR spectroscopy and X-ray diffraction analyses. Cp2#Co2(CO)As2S2 3 may be supposed to be the key intermediate in the whole reaction sequence: On heating solutions of 3 complexes 4-6 of higher nuclearity and different connectivity within the inorganic ligand were formed.
    Additional Material: 5 Ill.
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    URL: http://dx.doi.org/10.1002/cber.19961290611
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    Oligophosphane Ligands, XLIPart XL: A Saare, L. Dahlenburg, Z. Naturforsch. B: Chem. Sci. 1995, 50, 1009-1017.. Oxidative Additions of Transition Metal-Hydrogen Bonds: Reactions of CpM(CO)3H (M = Mo, W) with [tBuP(CH2CH2CH2PPh2)2]M′Cl(M′ = Rh, Ir)Dedicated to Professor Dr. Erwin Weiß on the occasion of his 70th birthday. (1996)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 129 (1996), S. 677-682 
    Details
    ISSN: 0009-2940
    Keywords: Oligophosphane complexes ; Metal-Hydrogen bonds ; Hydrogen transfer ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Treatment of (PP2)IrCl[PP2 = tBuP(CH2CH2CH2PPh2)2] with an equimolar quantity of CpM(CO)3H (M = Mo, W) or with HCl in THF resulted in smooth protonation of the d8 substrate producing [(PP2)Ir(H)Cl]X {X- = [CpMo(CO)3]- (1), [CpW(CO)3]- (2), Cl- (3)}. Combination of (PP2)IrCl and CpM(CO)3H in a 2:1 stoichiometry gave (PP2)Ir(H)Cl2 (7) together with [(PP2)IrCO]-[Mo(CO)3Cp] (8) or [(PP2)IrCO][W(CO)3Cp] (9). The rhodium analogues (PP2)Rh(H)Cl2 (4), [(PP2)RhCO][Mo(CO)3Cp] (5), and [(PP2)RhCO][W(CO)3Cp] (6) were obtained similarly from (PP2)RhCl and CpM(CO)3H. Structural assignments for [(PP2)Ir(H)Cl]+ and (PP2)M′(H)Cl2 (M′ = Rh, Ir) as diastereomers in which the hydrido ligand and the tBu substituent on the central phosphorus atom are located on the same side or on opposite sides of the PP2 reference plane of the meridionally bound tBuP(CH2CH2CH2PPh2)2 ligand are made on the basis of (i) correlations with known structures and reactivities of similar [(RP(CH2CH2CH2PR′2)2M′(H)Cl]+ cations and (ii) an X-ray structure determination of 4. The crystal structure analysis of a [(PP2)RhCO]+ salt, closely related to 5/6 and 8/9, [(PP2)Rh(CO)][OCO2H] (10), demonstrates that in the solid state the four-coordinate [(PP2)RhCO]+ cation and its counterion exist as essentially charge-neutralized Rh⃛O-contacted ion pairs, two of which are linked by O—H⃛O bridges to centrosymmetric dimers. Ion pairing was also observed by IR spectroscopy for THF solutions of metalates 5/6 and 8/9.
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    Electrochemical Preparation of Nanostructured Titanium Clusters: Characterization and Use in McMurry-Type Coupling Reactions (1996)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 129 (1996), S. 741-743 
    Details
    ISSN: 0009-2940
    Keywords: Clusters ; Transmission electron microscopy ; Low-valent titanium ; Olefin formation ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The electrochemical preparation of nanostructured titanium clusters is possible by using a titanium sacrificial anode as the metal source and tetrabutylammonium bromide in THF as the electrolyte and stabilizer. Transmission electron microscopy shows the presence of spherical 3.0-nm-sized particles. THF solutions of these Ti clusters induce olefin-forming McMurry-type coupling of aldehydes and ketones.
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    Metal hydroborates and hydroborato metalates, 21Part 20: Ref.[1].. Solvates of lithium (dimethylamino)trihydroborateDedicated to Professor H. W. Roesky on the occasion his 60th birthday. (1996)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 129 (1996), S. 451-458 
    Details
    ISSN: 0009-2940
    Keywords: Borate lithium (dimethylamino)trihydrido- ; TMEDA complex ; Dioxane complex ; 12-Crown-4 complex ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Li(Me2NBH3) (1) was prepared by deprotonation of Me2NH BH3 with LiBu and its solubility determined in various solvents. Compound 1 is unstable in most ethereal solvents and decomposes in a reversible reaction into LiH and Li-(Me2N—BH2—NMe2—BH3) (2). Five solvates of 1 were characterised by X-ray structure analysis. Li(Me2NH3) · TMEDA is a dimer in the solid state, and two units are connected to one another by B—H…Li bonds. The crystal structure of Li(Me2NBH3) · 0.5 dioxane is represented by layers consisting of tetrameric Li(Me2NBH3) units connected via dioxane molecules. Each Li atom is coordinated to one oxygen atom, one nitrogen atom, and two hydrogen atoms. Also Li(Me2NBH3) · 0.5 O2C3H6 forms an extended layer, however with pentacoordinated Li atoms which bear one oxygen, one nitrogen, and three hydrogen atoms. A similar layer structure was also found for Li(Me2NBH3) · O3C3H6 where each Li atom is bound to two oxygen atoms of different trioxane molecules, one nitrogen atom, and two hydrogen atoms. Finally, Li(Me2NBH3) · 12-crown-4 retains its molecular integrity in the solid state. Its Li atom is pentacoordinated by four oxygen atoms and one nitrogen atom.
    Additional Material: 11 Ill.
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    Derivate des Imidazols, XVII. Synthese und Eigenschaften von Dichlor(1,3-dimethyl-2-imidazol-2-ylidenimino)-phosphan - ein Methylenamino-Substituent mit ungewöhnlichen DonoreigenschaftenHerrn Professor Kurt Dehnicke zum 65. Geburtstag gewidmet. (1996)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 129 (1996), S. 479-482 
    Details
    ISSN: 0009-2940
    Keywords: Phosphanes ; Phosphazanes ; Methyleneamine ; Imidazoles ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Imidazole Derivatives, XVII. - Synthesis and Properties of Dichloro(1,3-dimethyl-2-imidazol-2-ylidenimino)phosphane - a Methylenamino Substituent with Uncommon Donor PropertiesDichloro(1,3-dimethyl-2-imidazol-2-ylidenimino)phosphane (5) is obtained from 1,3-dimethyl-2,3-dihydro-2-trimethylsilyliminoimidazole (4) and PCl3 in almost quantitative yield. Strong PN-π interaction (5B) is revealed by its X-ray structure analysis [P(1)-N(1) 1.579(2) Å]. AlCI3 causes chloride abstraction to give the cationic cyclophosphazane 8 identified by NMR spectroscopy.
    Additional Material: 1 Ill.
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    Disiloxanes, Disilazanes and Related Compounds Derived from 1,8-DisilynaphthaleneDedicated to Frau Professor M. Baudler on the occasion of her 75th birthday. (1996)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 129 (1996), S. 495-501 
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    ISSN: 0009-2940
    Keywords: 1,8-Disilylnaphthalene ; Disiloxane ; Disilthiane ; Disilazanes ; Phosphonium bis(silyl)methylide based on 1,8-disilylnaphthalene ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The synthesis, spectroscopic data and molecular structures of heterocycles derived from 1,8-disilylnaphthalene are reported. The key intermediate for the preparation of the title compounds is 1,8-bis[(trifluoromethylsulfonyl)silyl]naphthalene (3), which is prepared from 1,8-bis[(4-methoxyphenyl)silyl]naphthalene (2) by treatment with two equivalents of triflic acid in toluene at -20°C. The resulting silyl triflate is stable only below this temperature and was not isolated. Its reactions with water, ammonia, amines, and sulfane give the corresponding disiloxane, disilazanes and disilthiane. The molecular structure of Si,Si′-(Naphthalene-1,8-diyl)-N-phenyldisilazane (8) was determined by X-ray diffraction. Treatment of 2 with substoichiometric amounts of triflic acid and subsequent reaction of the resulting monosilyl triflate with tert-butylamine gives a related chiral N-tert-butyl-Si-(4-methoxyphenyl)disilazane 10. Its molecular structure was proven by X-ray diffraction. A cyclic phosphonium bis(silyl)methylide (11) was synthesized by a transylidation process using 3 and CH2=P(NMe2)3. The structure of 11 was also determined by X-ray diffraction.
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    URL: http://dx.doi.org/10.1002/cber.19961290505
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    Analysis of 13C and 17O Chemical Shift Tensors and an ELF View of Bonding in Fe2(CO)9 and Rh6(CO)16Dedicated to Professor Hans Georg von Schnering on the occasion of his 65th birthday. (1996)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 129 (1996), S. 527-533 
    Details
    ISSN: 0009-2940
    Keywords: Density functional theory ; Electron localization function ; NMR chemical shift tensor ; Transition-metal carbonyl clusters ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Carbon and oxygen chemical shift tensors for bridging and terminal carbonyl ligands in Fe2(CO)9 and Rh6(CO)16 were calculated by sum-over-states density-functional perturbation theory (SOS-DFPT). Agreement with experimental 13C shift tensors is excellent, and 17O shift tensors are predicted. The reduced anisotropy values of the shift tensors for the bridging compared to terminal carbonyl ligands are due to large deshielding contributions to δ33 from non-bonding or bridge-bonding orbitals. Comparison to recent computational results for a series of unusual piano-stool and bent-sandwich group-4 complexes is made. The electronic structures of the clusters are discussed by using plots of electron localization functions (ELF). Bonding electrons within the Rh6 cluster are mainly localized on the unbridged octahedral faces. This leads to a heterocubane-like arrangement of ELF maxima above all octahedral faces (four bridging CO ligands, four M-M 3-center-bonding maxima), in analogy to previous results for B6H62-.
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    URL: http://dx.doi.org/10.1002/cber.19961290509
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    Contribution to the Chemistry of Boron, 232Part 231: Ref.[1].. Formation, Structure and Reactions of a P,P′-Bi(1,3,2,4-diphosphadiboretane)Dedicated to Prof. Dr. O. J. Scherer on the occasion of his 60th birthday. (1996)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 129 (1996), S. 557-560 
    Details
    ISSN: 0009-2940
    Keywords: PC cleavage ; P,P′-Bi(1,3,2,4-diphosphadiboretane), 3,3′-di-tert-butyl-2,2′,4,4′-tetrakis-(tetramethylpiperidino)- ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Photolysis of the 1,3,2,4-diphosphadiboretane (tBuPBtmp)2 (1) in dilute toluene solution yields the bicyclic diphosphadiboretane 2. In concentrated toluene solution or in hexane, however, the P,P′-connected bi(diphosphadiboretane) 4 is also formed implying that the radical [tBuP(Btmp)2P] 3 is the first photolysis product. On further photolysis, 3 and 4 are converted into bicyclic 2 as the final product. Reduction of 4 with sodium-potassium alloy followed by silylation with Me3-SiCl leads to the 1,3,2,4-diphosphadiboretanes (tmpBP-SiMe3)2 and [HP(Btmp)2PSiMe3]2. In contrast to many 1,3,2,4-diboretanes, 4 in the absence of photon or thermal promotion does not react with Cr(CO)5 · THF, Fe2(CO)9, or Pd(PPh3)4. However, a mixture of Cr(CO)5 · THF and 4 on photolysis gives the known complex (tmpBP)2 · 2 Cr(CO)5.
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    URL: http://dx.doi.org/10.1002/cber.19961290513
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    Masthead (1996)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 129 (1996) 
    Details
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19961290601
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    Novel Ferrocene-Based Mono- and Bifunctional Tri-1-pyrazolylborate Ligands (1996)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 129 (1996), S. 603-606 
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    ISSN: 0009-2940
    Keywords: Ferrocenylboranes ; Tri-l-pyrazolylborate ligands ; Oligometallic complexes ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The reaction of (dibromoboryl)ferrocene (1a) with pyrazole/NEt3 gave the ferrocenyltri-1-pyrazolylborate ligand 2. Its thallium(I) derivative 2-Tl provides the first example of a polymeric structure with bridging tri-1-pyrazolylborate units in the solid state. The trinuclear iron complex 2-Fe, which is related to 1,1′-terferrocene, was obtained by reaction of 2 with FeCl2. The bis(polydentate) ligand 1,1′-ferrocenediyl-bis(tri-1-pyrazolylborate) (3-Li) was prepared from 1,1′-bis-[bis(dimethylamino)boryl]ferrocene (1c) and a mixture of lithium pyrazolide/pyrazole in refluxing toluene/THF. 3-Li reacts with TlNO3 to give the thallium(I) complex 3-Tl.
    Type of Medium: Electronic Resource
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    Chiral Organometallic Reagents, XX. An Enantiomerically Enriched (α-Phenylselenoalkyl)magnesium Compound (1996)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 129 (1996), S. 633-638 
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    ISSN: 0009-2940
    Keywords: Grignard reagents, α-seleno-substituted ; Kinetic resolution ; Racemization ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: α-Selenoalkyl Grignard reagents 2 are chiral. On reaction with the magnesium chelate 3a of α-benzyloxypropionaldehyde they show significant degrees of kinetic resolution, especially when the reactions are run in CH2Cl2. Under these conditions, racemic 2 was resolved by reaction with 0.59 equivalents of 3a at temperatures below -20°C. The remaining 2 had an enantiomer enrichment of 80-86% e.e. (as found by trapping). Hence, 2 has a considerably higher configurational stability than its lithium counterpart 1.
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    cis- and trans-Dimolybdenum(II) Complexes with Asymmetrically 2,7-Disubstituted Naphthyridines as Bridging Ligands (1996)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 129 (1996), S. 683-689 
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    ISSN: 0009-2940
    Keywords: Dimolybdenum(II) complexes ; Substituted naphthyridines ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Treatment of [Mo(CO)6] with Hmamnp (2-acetamido-7-methyl-1,8-naphthyridine) in diglyme at 100°C affords the mononuclear complex [Mo(CO)4(Hmamnp)] 1, an intermediate product on the reaction pathway to tetrasubstituted species of the type [Mo2L4]. A disubstituted intermediate product cis-[Mo2(mphamnp)2(OAc)2] 2 (Hmphamnp) (2-acetamido-5-methyl-7-phenyl-1,8-naphthyridine) may be isolated from the reaction of [Mo2(OAc)4] with mphamnp- in THF. The relative stabilisation of such products is a result of the steric demands of the coplanar 2-acetamido substituents. 2 and the tetrasubstituted complexes trans-[Mo2(mbznnp)4] 3 (Hmbznnp = 2-benzylamino-7-methyl-1,8-naphthyridine), cis-[Mo2(mphonp)4] 4, and trans-[Mo2(mphonp)4] 5 (Hmphonp = 5-methyl-7-phenyl-1,8-naphthyridin-2-one) all exhibit the electronically prefered μ-N1,X2 bridging mode. Steric effects are responsible for the isolation of the unusual cis isomer 4.
    Additional Material: 5 Ill.
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    Dithio and Thiono Esters, 62Part 61: K. Hartke, S. Barrmeyer, J. Prakt. Chem., in press.. Reactions of Alkanedithioic Acid Dianions with Iodine, Sulfur, and Tin CompoundsDedicated to Prof. Dr. Kurt Dehnicke on the occasion of his 65th birthday. (1996)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 129 (1996), S. 663-669 
    Details
    ISSN: 0009-2940
    Keywords: Alkanedithioic acid ; Dithiocarboxylic acid ; 1,2-Dithiine ; 1,2,4-Trithiolane ; 1,2,3,4-Tetrathiane ; 1,3,2-Dithiastannetane ; Thioacyltin sulfide ; Bis(thioacyl)tin sulfide ; 1,2,3,4,5,6-Hexathiepane ; 1,2,3,5,6,7-Hexathiocane ; 1,2,3,5,6-Pentathiepane ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The monoanion of the alkanedithioic acid 1a is oxidized with hypervalent iodine compounds to form the 1,2-dithiine 6, the monoanion of 1b yields the 1,2,4-trithiolane 7 and the dianions 2b, c furnish the 1,2,4,5-tetrathianes 3b, c. With diphenyltin or dimethyltin dichlorides 8 the monoanions of 1b, c afford the monothioacyl or bisthioacyl organotin sulfides 10a-c or 11a, b respectively. When treated with lithium hexamethyldisilazane, 10b undergoes an intramolecular cyclization to the 1,3,2-dithiastannetane 9b; 10a is deprotonated by triethylamine to the 1,3,5-trithia-2-stanninane 13. The dianion 2c reacts with diphenyltin dichloride 8 to yield the 1,3,2-dithiastannetane 9d, with dimethyltin dichloride the 1,2,4-trithiolane 16 is formed. 9d is cleaved by thionyl chloride, sulfur dichloride, and disulfur dichloride to give a complex mixture of the 1,2,4,5-tetrathiane 3c and the cyclic polysulfides 1,2,3,4,5,6-hexathiepane 18, 1,2,3,5,6,7-hexathiocane 19 and the 1,2,3,5,6-pentathiepane 20 in varying amounts. Reaction of the dianion 2b with thionyl chloride leads to the formation of the 1,2,4,5-tetrathiane 3b as main product; byproducts are cyclic polysulfides, the 1,2,3,5,6-pentathiepane 21 and the 1,2,3,4,5,6-hexathiepane 22.
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    Neue Phospholen- und Phosphepin-Derivate aus λ3-Phosphorverbindungen und Hexafluoraceton oder perfluorierten α-DiketonenHerrn Professor Herbert Schumann zum 60. Geburtstag gewidmet. (1996)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 129 (1996), S. 725-732 
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    ISSN: 0009-2940
    Keywords: Phospholenes ; Phosphepines ; Ring expansion reactions ; Perfluorinated diketones ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: New Phospholene and Phosphepine Derivatives from λ3-Phosphorus Compounds and Hexafluoroacetone or Perfluorinated α-DiketonesThe reaction of the bis(2-chloroethyl)amino-substituted benzoxazaphosphorinone 1 with hexafluoroacetone (HFA) proceeds with insertion of the carbonyl group of HFA into the heterocycle of 1 to form the oxazaphosphepinedione 2. Triethyl phosphite (3) and triphenyl phosphite (4) react with the perfluorinated diketones 5 and 6 with formation of the pentaoxyphosphoranes 7-10 containing a dioxaphospholene ring system. The reaction of the (2-chloroethyl)amino- and bis(2-chloroethyl)amino-substituted 1,3,5,2-triazaphosphorinanediones 11-14 with the perfluorinated diketone C2F5C(:O)C(:O)CF3 (15) furnishes spirophosphorane derivatives with the dioxaphospholene ring system, 16 and 17, in two cases only. Compound 1 and 2-[bis(2-chloroethyl)-amino]-4H-1,3,2-benzodioxaphosphorin-4-one (18) react with the perfluorinated α-diketones 5 and 6 with insertion of the diketones into the heterocycle of 1 and 18 with formation of compounds 19-22 containing dioxa- and oxazaphosphepinone ring systems. The expected oxidative addition of the diketones to λ3P with formation of spirophosphoranes was not observed. Compounds 19-22 were obtained as mixtures of isomers (19a/b-22a/b). Single crystal X-ray structure analyses were conducted on 2 and 9. The seven-membered ring of 2 displays a “tub” conformation, with the O and benzo C atoms lying out of the plane of the other four atoms. The two independent molecules of 9 are similar, but differ in the degree of distortion from trigonal-bipyramidal geometry of phosphorus.
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    Hexacoordinated Group-14 Elements with Phosphorus Donor Ligands: Syntheses and Structures of Me2E[C(PMe2)2(SiMe3)]2 (E = Si, Ge, Sn) (1996)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 129 (1996), S. 759-764 
    Details
    ISSN: 0009-2940
    Keywords: Hexacoordination ; Silicon compounds ; Germanium compounds ; Tin compounds ; Phosphanylmethanide ligands ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The dimethyl group-14 element dihalides Me2EX2 (E = Si, Ge, Sn; X = Cl or Br) react with two equivalents of Li[C(P-Me2)2(SiMe3)] to give the cis-hexacoordinated complexes Me2E[C(PMe2)2 (SiMe3)]2 (E = Si: 2a, E = Ge: 2b, E = Sn: 2c), which were characterized spectroscopically and by means of X-ray structure determinations. Whereas 2a and 2b are isotypic and crystallize in the space group P21/c, 2c crystallizes in the space group C2/c with crystallographic C2(2) molecular symmetry. In all cases the diphosphanylmethanide ligands bind in an unisobidentate fashion. For compound 2c, this still can be attributed to the trans influence of the methyl group, but in 2a and 2b clearly borderline cases between hexa- and tetracoordination are found. Compound 2b (E = Ge) is much more on the side of tetracoordination than 2a, thus underlining the importance of small polarity differences for the actual coordination number achieved in compounds with relatively unpolar bonds.
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    Cyclobutadiene Complexes, XIIPart XI: Ref.[28].. Alkynyl-Substituted Tricarbonyl(cyclobutadiene)iron Complexes: Stille Coupling of Iodocyclobutadiene Complexes with StannylalkynesDedicated to Professor Dr. Heinrich Nöth. (1996)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 129 (1996), S. 785-797 
    Details
    ISSN: 0009-2940
    Keywords: Alkynylation ; Palladium catalyzed coupling reactions ; Cyclobutadiene complexes ; Iron complexes ; Cobalt complexes ; Modular chemistry ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The synthesis of mono-, di-, tri- and tetraalkynylated tricarbonyl(cyclobutadiene)iron complexes is accomplished by a repetitive metalation/iodination/coupling sequence. Application of this sequence leads to the synthesis of oligomeric cyclobutadiene complexes with various topologies, inter alia to the synthesis of a perethynylated dimer 24. Alternatively a one-step coupling procedure (Stille-Farina) has been used to synthesize tetraalkynylated tricarbonyl(cyclobutadiene)-irons 26.
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    (Di-tertbutylmethylsilyl)amide - a Building Block for Azasilacyclobutane Synthesis (1996)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 129 (1996), S. 823-828 
    Details
    ISSN: 0009-2940
    Keywords: Aminosilanes ; Lithium compounds ; 1,3-Diaza-2,4-disilacyclobutanes ; 1-Aza-2,4-disilacyclobutane ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Di-tert-butylmethylsilylamide reacts with n-BuLi to give the tetrameric lithium di-tert-butylmethylsilylamide 1. Reactions of lithium (di-tert-butylmethylsilyl)amide 1 with SiF4 give the mono- (2), bis- (3), tris- (4), and tetrakis- (5) -[(di-tert-butylmethylsilyl)amino]silanes. Lithiated 3 reacts with Me3SiCl to form (di-tert-butylmethylsilyl-trimethylsilyl)amino-(di-tert-butylmethylsilyl)amino-difluorosilane (6); the 1,3-diaza-2,4-disilacyclobutane 7 is obtained by LiF elimination. The lithium derivative of 6 (compound 8) crystallizes with formation of a (SiFNLi) four-membered ring system. The 19F-NMR spectrum proves that the Li-F bond fluctuates in solution. Reactions of 1 with (Me3Si)2C(SiF3)2 afford different products (9, 10) by controlling the reaction sequence. An excess of 1 reacts to give a four-membered CSi2N ring system, the 1-(di-tert-butylmethylsilyl)-2,4-bis-[(di-tert-butylmethylsilyl)-amino]-2,4-difluoro-3-bis(trimethylsilyl)-1-aza-2,4-disila-cyclobutane (9), disubstitution with formation of bis[(di-tert-butylmethylsilyl)aminodifluorosilyl]bis(trimethylsilyl)methane (10) occurs in a molar ratio of 2:1. The cyclodisilazane 11 is obtained from dilithiated 10 in an intramolecular interconversion reaction. The crystal structures of 1, 8, 9, and 11 are reported.
    Additional Material: 4 Ill.
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    Iron-Mediated Conversions of Eucarvone-Derived Cationic Dienyl Complexes (1996)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 129 (1996), S. 845-851 
    Details
    ISSN: 0009-2940
    Keywords: Cationic cycloheptadienyl iron complexes ; Eucarvone ; Nucleophilic attack ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Cationic cycloheptadienyl iron complexes with new substitution patterns are generated by starting from the eucarvone complex 5 and the analogous triphenyl phosphite complex 6. These complexes are converted with different nucleophiles. Regioselectivity of the nucleophilic attack depends on the substitution pattern of the seven-membered ring. A new type of cationic system 7b, bearing an alkoxy substituent at C-1, was treated with nucleophiles leading to the ipso adducts of type 10. Unexpected attack at the central C-3 of the dienyl moiety is observed during the conversion of cationic complexes of type 9 with nucleophiles. The diene iron complexes, obtained in these reactions, can be converted to substituted cycloheptadienes by oxidative decomplexation, as shown by a selected example.
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    URL: http://dx.doi.org/10.1002/cber.19961290718
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    Synthesis and Structure of Methoxybis[tris(trimethylsilyl)silyl]methane - The First Geminal Di(hypersilyl) Compound with a Central Carbon Atom (1996)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 129 (1996), S. 841-844 
    Details
    ISSN: 0009-2940
    Keywords: Methane, methoxybis[tris(trimethylsilyl)silyl- ; Tris(trimethylsilyl)silyllithium ; Dichloromethyl methyl ether ; Polysilanes ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Methoxy-bis[tris(trimethylsilyl)silyl]methane (4), the first compound bearing two hypersilyl groups at a carbon atom, was synthesized by the reaction of tris(trimethylsilyl)silyllithium with dichloromethyl methyl ether. As a byproduct of the reaction, 1,2-dimethoxy-1,2-bis[tris(trimethylsilyl)silyl]-ethane (5) could be identified. Possible pathways leading to 4 and 5 are discussed. The structure of 4, elucidated by an X-ray crystal structure analysis, is characterized by tremendous distortions of the molecular skeleton due to the spatial demand of the two extended hemispherical (Me3Si)3Si groups. For example, the central Si-C-Si angle is widened to 132.7°, the trimethylsilyl groups of the two hypersilyl substituents are pressed together to give an average Si-Si-Si angle of 105.6°, and the methoxy carbon atom and the nearest neighboring trimethylsilyl carbon atom approach to a distance of 3.25 Å, i.e. approx. 19% less than the sum of the van der Waals radii of two methyl groups.
    Additional Material: 1 Ill.
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    URL: http://dx.doi.org/10.1002/cber.19961290717
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    Metall-π-Komplexe von Benzolderivaten, 50Part 49: Ref.‘1’.. Arylborane als Sandwichliganden: Darstellung von [(iPrO)2B(η6-Ph)]2M und [Mes2B(η6-Ph)]2M (M = V, Cr). Redoxeigenschaften und EPR Untersuchung M(d5)-konfigurierter Neutralkomplexe sowie Bor-zentrierter Radikalanionen (1996)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 129 (1996), S. 871-878 
    Details
    ISSN: 0009-2940
    Keywords: Bis(arene)metal complexes ; Borane, dimesitylphenyl- ; Borane, diisopropylphenyl- ; Cyclic voltammetry ; EPR spectroscopy ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Metal π Complexes of Benzene Derivatives, 50. - Arylboranes as Sandwich Ligands: Preparation of [(iPrO)2B(η6-Ph)]2M and [Mes2B(η6-Ph)]2M (M = V, Cr). Redox Properties and EPR Study of M(d5) Neutral Complexes and Boron-Centered Radical AnionsBis(η6-arene)metal complexes bearing peripheral boryl substituents have been prepared by means of metal-atom ligand-vapor cocondensation leading to [(iPrO)2B-η6-C6H5]2Cr (7) and [(iPrO)2B-η6-C6H5]2V (8) as well as by lithiation and subsequent reaction with Mes2BF with formation of [Mes2B-η6-C6H5]2Cr (11) and [Mes2B-η6-C6H5]2V (12). According to the NMR spectra, rotation about the η-C-BR2 bonds in 7 and 11 is free at 25°C, restrictions setting in at -85°C. The neutral radicals 8• and 12• have been studied by EPR spectroscopy: despite of the profound difference in the electron-accepting properties of the groups (iPrO)2B- and Mes2B, the hyperfine coupling constants a(51V) differ by 5% only; the extent of perturbation of the electronic structure manifests itself more clearly in the g tensor, which is tetragonal for 8 but orthorhombic for 12, the degeneracy of the LUMO's e1g being raised in the latter. Cyclovoltammetry on 11 exhibits reversible oxidation as well as reduction processes. Reduction which, according to EPR, is ligand-centered, occurs in two steps which are separated by the redox splitting ΔE1/2 = 570 mV. This value, which is a measure of electronic communication between the two Mes2B groups, lies between those of 1,4-bis(dimesitylboryl)benzene (δE1/2 = 690 mV) and 4,4′-bis(dimesitylboryl)biphenyl (ΔE1/2 = 270 mV). The EPR spectrum of the radical anion 11-• reveals hyperfine coupling to one boron nucleus of a magnitude very similar to that of the free ligand radical anion Mes2BC6H5-•. Therefore, reduction of 11 is ligand-centered, and an intramolecular electron exchange between the boron centers is slow on the EPR time scale. As inferred from the observation of the hyperfine interactions a(53Cr) and a(1H), oxidation of 11 is metal-centered; relative to parent bis(η6-benzene)chromium (9), the two Mes2B groups cause an anodic shift of 290 mV for the couple 11+/0. The radical cations 11+• are prone to protodeborylation, in this aspect resembling the respective silyl derivatives.
    Additional Material: 6 Ill.
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    Diphosphonio-1,2-diphospholes: Structural PIII/Pv Hybrids (1996)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 129 (1996), S. 1083-1086 
    Details
    ISSN: 0009-2940
    Keywords: Phospholes ; Diphospholes ; Phosphonio substitution ; Methylation ; Pyramidal and planar three-coordination ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: P-Methylation of the 3,5-bis(triphenylphosphonio)-1,2-diphospholide 1 leads to the dicationic diphosphole 3a. A crystal of its bis(triflate) was used for a structure analysis. It indicates that in contrast to the known phospholes the cyclic π6 system is preserved in 3a. The coordination geometry of the methylated phosphorous atom shows a flat pyramid with a sum of angles of 339°. Therefore, 3a represents a state that is intermediate between a phosphane and a bis(methylene)phosphorane, i.e. between PIII and Pv.
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    Diboran(4)yl Groups as Ligands to Transition Metals (1996)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 129 (1996), S. 1099-1101 
    Details
    ISSN: 0009-2940
    Keywords: Diboranes ; Transition-metal boryl complexes ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Reaction of Na[(Cp)Fe(CO)2] and Na[(Cp)W(CO)3] with B2(NMe2)2Cl2 yields the first transition metal-substituted diboranes [Cl(Me2N)B-B(NMe2)M(Cp)(CO)n] [M(Cp)(CO)n = Fe(Cp)(CO)2, W(Cp)(CO)3] (1a, b). The compounds were characterized in solution by NMR methods and in the crystal by X-ray structural determination.
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    URL: http://dx.doi.org/10.1002/cber.19961290919
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    Azidopentazole is Probably the Lowest-Energy N8 Species - A Theoretical Study (1996)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 129 (1996), S. 1157-1159 
    Details
    ISSN: 0009-2940
    Keywords: N8 Isomers ; Azidopentazole ; Calculations, ab initio ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Ab initio molecular orbital calculations at the quadratic configuration interaction [QCISD(T)/6-31G(d)] and coupled-cluster theory [CCSD(T)/DZP] levels based on MP2/6-31G(d) optimized geometries show that azidopentazole is likely to be the global minimum of the N8 isomers lying 13 and 18 kcal/mol below the acyclic diazidyldiimide and the cyclic pentalene analogue, respectively. Azidopentazole is characterized by a significant energy barrier to ring closure and is expected to be stable with respect to cycloreversion and thus constitutes the most realistic N8 target for a synthetic preparation.
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    Activation of Bis(trimethylsilyl) Peroxide and tert-Butyl Hydroperoxide with Oxo and Peroxo Complexes of Vanadium, Molybdenum, and Tungsten for the Sulfoxidation of Thianthrene 5-Oxide (1996)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 129 (1996), S. 1177-1182 
    Details
    ISSN: 0009-2940
    Keywords: Thianthrene 5-oxide ; Peroxide, bis(trimethylsilyl) ; Hydroperoxide, tert-butyl ; Oxygen transfer ; Peroxo complexes ; Catalysis ; Vanadium ; Molybdenum ; Tungsten ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Bis(trimethylsilyl) peroxide (BTSP) and tert-butyl hydroperoxide (tBuOOH) were activated by various oxo and peroxo complexes of molybdenum, tungsten, and vanadium as catalysts for the sulfoxidation of thianthrene 5-oxide (SSO). A screening of a number of phosphane oxide and amine oxide ligands revealed that BTSP was most efficiently activated by the [MoO5(OPtBu3)] complex. The best results for tBuOOH as oxygen source were achieved with the vanadates [VO(OR)3] (R = tBu, iPr). Comparative selectivity and rate data for the stoichiometric and catalytic sulfoxidations of SSO mediated by the MoO5L complex (L = OPtBu3, OPnOct3, ONnBu3, ONnOct3) suggest that the bisperoxo metal complex is the active oxygen transfer species.
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    URL: http://dx.doi.org/10.1002/cber.19961291006
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    Fluxionality and Phosphane Arm-off Reactions of Octahedral Rhodium(III) Complexes with the Tripodal Polyphosphane MeC(CH2PPh2)3 (1996)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 129 (1996), S. 1199-1206 
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    ISSN: 0009-2940
    Keywords: Rhodium(III) complexes ; Triphos complexes ; Arm-off dissociation ; Fluxional behaviour ; Dialkyldithiocarbamate complexes ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Treatment of [RhCl3(triphos)] or [Rh(MeCN)3(triphos)](CF3SO3)3 [triphos= MeC(CH2PPh2)3] with Na(S2C-NEt2) affords the complexes [RhCl(S2CNEt2)(triphos)]Cl (1) and [Rh(S2CNEt2)(MeCN)(triphos)](CF3SO3)2 (2). Whereas 1 is stereochemically rigid in solution at 25°C, 2 and the analogous complex [Rh(S2CNBz2)(MeCN)(triphos)](CF3SO3)2 (3) exhibit a rapid exchange of their phosphorus environments. In contrast, the 31P-NMR spectra of both 2 and 3 at -30°C consist of well-resolved A2MX spin systems. k2P-coordinated complexes of the type [Rh(S2CNR2)2(triphos-k2P)]+ (R = Et 4, R = Me 5) with ABX spin systems may be obtained by treatment of the starting compounds with two equivalents of the respective dialkyl dithiocarbamate. The dangling phosphane arm can be readily oxidised to a phosphane oxide as in [Rh(S2CNEt2)2(triphosO-k2P)]Cl (6) [triphosO = O=P(Ph)2CH2C(Me)(CH2PPh2)2]. The analogous compound [Rh(mpy)2(triphosO-k2P)]Cl (7) (Hmpy = 2-mercaptopyridine) was isolated as the OC-6-13 isomer with trans-positioned sulphur atoms, a siting which is in accordance with a reaction mechanism involving a phosphane arm-off k3P' k3P dissociation equilibrium.
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    Electrophilic Substitution at the NB9 and NB11 closo-SkeletonsDedicated to Professor Kurt Dehnicke on the occasion of his 65th birthday (1996)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 129 (1996), S. 1227-1231 
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    ISSN: 0009-2940
    Keywords: Aza-closo-decaboranes, halogenation of, methylation of ; Aza-closo-dodecaboranes, halogenation of, methylation of ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The aza-closo-boranes ArNB9H9 (1, Ar = p-ClC6H4) and MeNB11H11 (2) were brominated, iodinated, or methylated under Friedel-Crafts conditions to give ArNB9H4Br5 (3), ArNB9H7I2 (4), ArNB9H4Me5 (7), MeNB11H10Br (5), MeNB11H10I (6), and MeNB11H5Me6 (9), respectively. The upper boron belt adjacent to nitrogen is not involved in the substitution reactions with 1 and 2. The antipodal position and the lower belt are attacked by electrophiles in the case of 1; the antipodal position is the preferred one in the case of 2. By prolongated action of triflic acid on the methylated species 7 and 9, one methyl group is replaced by the triflate group to give ArNB9H4Me4(OTrf) (8) and MeNB11H5Me5-(OTrf) (10) with this group in the positions 6 and 12, respectively. The NMR data indicate the cluster symmetries Cs (4, 8), C4v (3, 7), and C5v (5, 6, 9, 10). Crystal structure investigations of 5 (space group Cc) and 10 (space group C2/c) showed that the molecular dimensions of the NB11 skeleton are comparable to those of closo, -(PhCH2)NB11H11.
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    A Palladium-Catalyzed Domino Coupling Process Leading to Annelated PentafulvenesDedicated to Professor Dr. Peter Sartori on the occasion of his 65th birthday. (1996)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 129 (1996), S. 1265-1269 
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    ISSN: 0009-2940
    Keywords: Domino coupling reactions ; Pentafulvenes ; Catalysis ; Palladacycles ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Annelated pentafulvenes 2, 10, 13, and 14 are efficiently accessible by a palladium-catalyzed domino coupling process of aryl substituted vinylic bromides 1, 9, 11, and 12, 5-Membered palladacycles 3 are discussed as key intermediates.
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    Reactions of Lactams with Titanocene- and Zirconocene-Alkyne Complexes as Elemental Steps in Catalytic Anionic Ring-Opening Polymerization of Lactams (1996)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 129 (1996), S. 1281-1285 
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    ISSN: 0009-2940
    Keywords: Zirconocenes ; Titanocenes ; N-Methyl-ε-caprolactam ; β-Propiolactam ; ε-Caprolactam ; Ring-opening polymerization ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Depending on the nature of the metal and the ring size, lactams react with titanocene and zircocene complexes of bis-(trimethylsilyl)acetylene Cp2Ti(Me3SiC2SiMe3) and Cp2Zr-(L)(Me3SiC2SiMe3) (L = Py, THF) to yield different products. In the reaction of Cp2Zr(Py)(Me3SiC2SiMe3) with N-methyl-€-caprolactam a simple ligand exchange reaction occurs and the complex Cp2Zr(Me3SiC2SiMe3)[O=H2)5] (1) was isolated. With β-propiolactam the alkenyl-amido complex Cp2)(SiMe3)][-NH2] (2) was obtained, which indicates that an agostic metal-hydrogen interaction has taken place. The reaction of Cp2Ti(Me3-SiC2SiMe3) with €-caprolactam gives after elimination of the alkyne and molecular hydrogen the first early transition metal complex with a deprotonated coordinated €-caprolactam in a η2-amidate bonding fashion (3). The obtained complexes were characterized by NMR spectra (1, 2) and crystal structure analysis (1-3) and discussed as elemental steps in anionic ring-opening polymerization of lactams catalyzed by metallocene-alkyne complexes.
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    URL: http://dx.doi.org/10.1002/cber.19961291022
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    Synthesis of Mono-, Di-, and Tri-arylgold(III) Complexes Using Organomercury Compounds - Synthesis of the First Aurated Schiff Bases (1996)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 129 (1996), S. 1301-1306 
    Details
    ISSN: 0009-2940
    Keywords: Synthesis aryl complexes of gold(III) ; Mercury(II) as transmetallating agent ; X-ray crystal structure ; Ketonylgold(III) complex ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The formylarylmercury(II) complex [Hg{C6H(CHO)-6-(OMe)3-2,3,4}2] reacts with 4-butylaniline (1:2) to give [Hg{C6H(CH=NC6H4C4H9-4′)-6-(OMe) 3-2,3,4}2] (1) by a condensation reaction. This complex reacts with Me4-N[AuCl4] (1:1) to give [Hg{C6H(CH=NC6H4C4H9-4′)-6-(OMe) 3-2,3,4}Cl] (2) and the monoarylgold(III) compound cis-C6H4-nBu-4′)-6-(OMe)3-2,3,4}Cl2] (3). This complex reacts with PPh3 (1:1) to give the adduct cis-[Au{C6H(CH=NC6H4-n, Bu-4′)-6-(OMe)3-2,3,4}Cl2(PPh3)] (4) and with AgClO4 (1:1) in acetone to give the ketonyl complex cis-[C6H4-nBu-4′)-6- (OMe)3-2,3,4}-{CH2C(O)Me}Cl] (5). cis-Me4N[Au(C6H4NO2-2)2Cl 2] react with [Hg{C6H3(N=NC6H4OMe-4′)-2-(OMe)-5}Cl] and Me4NCl (1:1:1) to give cis-[C6H4OMe-4′)-2- (OMe)-5}(C6H4NO2-2)2] (6): Similarly, cis-Me4N-[Au(C6H4CF3-2)2 Cl2] (7), obtained by treating [Hg(C6H4CF3-2)2] with Me4N[AuCl4] and Me4NCl (1:1:1), reacts with [Hg(C6H4CH2NMe2-2)Cl] and Me4NCl (1:1:1) to give the triarylgold(III) complex cis-[Me2-2)(C6H4CF3-2)2] (8). This complex can also be obtained by treating cis-[Me2-2)Cl2] with [Hg(C6H4CF3-2)2] and Me4NCl (1:1:1). The crystal structure of 3 reveals the presence of two independent molecules, in one of which the butylphenyl group is disordered. The geometry at the gold atom is square planar; distortions may be attributed to the narrow bite angle and steric repulsion between a chloride ligand and the ortho-methoxy group. The greater trans influence of the aryl ligand causes a great difference in Au-Cl bond lengths.
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    Alkylammonium Hexachlorometallates, IVPart III: Ref.[1].. Synthesis and Crystal Structure of Bis(1,4-diammoniobutane) Diaquahydrogen Hexachlororhodate(III) Dichloride, [H3N-(CH2)4- NH3]2[H5O2][RhCl6]Cl2 (1996)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 129 (1996), S. 1355-1359 
    Details
    ISSN: 0009-2940
    Keywords: Hexachlororhodates ; 1,4-Diammoniobutane ion ; Diaquahydrogen ion ; Hydrogen bonding ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Bis(1,4-diammoniobutane) diaquahydrogen hexachlorohodate(III) dichloride, [H3N-(CH2)4 -NH3]2[H5O2][RhCl6]Cl2 (1), was synthesized by the reaction of rhodium(III) chloride with 1,4-diaminobutane dihydrochloride in concentrated hydrochloric acid. The red compound slowly decomposes at room temperature, but is stable for months and up to 106°C (DTA) under hydrogen chloride. Crystals of 1 were obtained by diffusion-controlled crystallization (space group P,1¯). The solid-state structure can be considered as a sequence of layers linked by hydrophobic interactions between the aliphatic chains of the 1,4-diammoniobutane ions. Within these layers the hydrophilic building blocks (hexachlororhodate and chloride anions, the diaquahydrogen cations and the ammonio groups of the diammoniobutane cations) are connected by a complex system of O—H-Cl and N—H-Cl hydrogen bonds. The H5O2+ ion has a crystallographically imposed Ci symmetry and shows the typical 1:1 disorder of the central hydrogen atom for a symmetrically strong [O-O 2.406(10) Å] doubleminimum potential O-H-O bond.
    Additional Material: 3 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19961291107
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    The d2-M(NR)2 Fragment, High Valent and Low Valent Organometallic Equivalents, and an Unusual Mode of Ethylene Complexation (1996)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 129 (1996), S. 1345-1353 
    Details
    ISSN: 0009-2940
    Keywords: Ethylene complexes ; Molecular orbital calculations ; Transition metal complexes ; Metal-nitrogen bonds ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: We report approximate molecular orbital calculations on models of the ethylene complex W(NMes)2(PMe3)2(η2-C2H4) 1. The ethylene unit in 1 is oriented perpendicular to the equatorial plane - an unusual orientation for trigonal bipyramidal L4M-(η2-C2H4) complexes. In order to understand the bonding in 1, the tungsten fragment W(NR)2L2 is discussed in some detail and we compare the “high valent” ethylene complex 1 and the “low valent” olefin complex Fe(CO)4(η2-C2H4). An analysis of π-bonding shows that the metal nitrogen bond in the cis,-[M(NR)2] unit is less than a triple bond, and the d2-[M(NR)L2] fragment is more like a 16 than an 18 valence electron fragment. The nature of the occupied d-orbital explains the opening of the angle E-M-E in trigonal bipyramidal complexes d2-cis-M(E)2L3. Both C2v fragments d2-W(NR)2L2 and d8-Fe(CO)4 have characteristic frontier orbitals, qualitatively similar to the frontier orbitals of CH2. These orbitals guide the ethylene ligand into or out of the equatorial plane. The general analysis leads to the conclusion that dn (n 〉 O) “high valent” complex fragments are actually better back-bonding donors for π-acidic ligands. For 1, we detect also another mininum on the energy surface - the olefin ligand is now oriented parallel to the equatorial plane. This raises the fascinating possibilities of the existence of multiple conformational minima for some transition metal ethylene complexes.
    Additional Material: 8 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19961291106
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  • 192
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    Interaction Modes of Titanium Tetrachloride with the Carbonyl Functionality (1996)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 129 (1996), S. 1361-1368 
    Details
    ISSN: 0009-2940
    Keywords: Lewis acid-carbonyl complexes ; Chiral oxazolidinone-TiCl4 adduct ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Mesityl aldehyde binds TiCl4 leading to the first structurally characterized TiCl4-aldehyde adduct, cis-[(MesCHO)2TiCl4] (Mes = 2,4,6-Me3C6H2) (1), which contains a pseudooctahedral titanium and two aldehyde carbonyl groups in a cis arrangement. However, in the case of 1:1 TiCl4-acetone adduct [(Me2CO)TiCl3)2(μ-Cl)2] (3) the solid-state structure of this acid-base complex is that of a chloro-bridged dimer. Both kinds of structures were suggested for the products [{(PhCOMe)TiCl3}2(μ-Cl)2] (4) and [cis-(PhCOMe)2TiCl4] (5) formed by the reaction of TiCl4 with acetophenone in 1:1 and 1:2 molar ratio. Thioesters behave like acetone in that they give adducts 8 and 9 with TiCl4, where 9, [{(PhSC(Me)O)TiCl3}2(μ-Cl)2], exhibits a solid-state dimeric structure like 3. The bidentate bonding mode of the chiral propionyloxazolidone 12 with TiCl4 was revealed by an X-ray analysis of 13.
    Additional Material: 4 Ill.
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    URL: http://dx.doi.org/10.1002/cber.19961291108
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  • 193
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    Preparation and Reactivity of Tris(trifluoromethylselanyl)carbenium [(CF3Se)3C+] and Trifluoromethylsulfanylacetic Acid Derivatives [(CF3S)3-nCXn(O)R]Dedicated to Professor Max Herberhold on the occasion of his 60th birthday. (1996)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 129 (1996), S. 1383-1388 
    Details
    ISSN: 0009-2940
    Keywords: Trifuoromethylselanyl ; Trifluoromethylsulfanyl ; Acetic acid ; Esters ; Halides ; Hexafluoroarsenate ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Reaction pathways for the synthesis of the (CF3E)3C moieties (E = Se, S) are described. [(CF3Se)3C+][AsF6-] was found to be a suitable synthon for the preparation of (CF3Se)3C derivatives. It can be prepared either from (CF3Se)3C derivatives. It can be prepared either from (CF3Se)4C or (CF3Se)3CF and AsF5 in liquid SO2. Direct access to (CF3Se)3CF was realized by the reaction of FCBr3 with Hg(SeCF3)2. Treatment of [(CF3Se)3C+][AsF6-] with potassium halides provided (CF3Se)3CX (X = F, Cl, Br). A different course took the reaction with KI, as CF3SeSeCF3 and (CF3Se)2C=C(SeCF3)2 were formed as main products. Minor amounts of (CF3Se)3CC(SeCF3)3 were formed which could be isolated and unambiguously characterized. Only two routes led to a threefold CF3S-substituted acetic acid ester (CF3S)3CC(O)OR [R = CH3, (CH3)3C]: Metatheses between (CF3S)2CBrC(O)OCH3 and Hg(SCF3)2 and metalation of (CF3S)2CHC(O)OR [R = CH3, (CH3)3C] with NaH followed by reaction with CF3SCl. Other precursors such as (CF3S)2CXC(O)OR′ [X = H, Br; R′ = Me3Si, (n-C4H9)3Sn] and (CF3S)2CBrC(O) Y (Y = Cl, Br) were synthesized but could not be converted to the corresponding (CF3S)3C derivatives. Attempts to hydrolyze (CF3S)3CC(O)OR to (CF3S)3CC(O)OH failed.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19961291112
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  • 194
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    Metall-π-Komplexe von Benzolderivaten, 49. Halbsandwichkomplexe des Trimesitylborans Mes3B: Darstellung und Struktur von Mes2B[η6-Mes)Cr(CO)3], MesB[η6-Mes)Cr(CO)3]2 und B[(η6-Mes)Cr(CO)3]3. Redoxverhalten und Fragen der intramolekularen Wechselwirkung (1996)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 129 (1996), S. 1407-1407 
    Details
    ISSN: 0009-2940
    Keywords: (Arene)tricarbonylmetals ; Borane, trimesityl ; Cyclic voltammetry ; MLCT transitions ; EPR spectroscopy ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19961291116
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  • 195
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    Reactions of Tetrakis[bis(trimethylsilyl)methyl]digallane(4) with Carboxylic Acids  -  Substituent Exchange and Bridging of the Ga—Ga bond by two Carboxylato GroupsDedicated to Prof. Dr. Walter Siebert, on the occasion of his 60th birthday. (1996)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 129 (1996), S. 1425-1428 
    Details
    ISSN: 0009-2940
    Keywords: Gallium - Gallium bonds ; Carboxylato bridges ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Yellow tetrakis[bis(trimethylsilyl)methyl]digallane(4) 1 reacts with two equivalents of the carboxylic acids RCOOH (R = -C6H5, -p-BrC6H4, -3,5-Me2C6H3, -CMe3) to yield almost quantitatively colorless products in which two bis(trimethylsilyl)methyl groups are replaced by two carboxylato ligands. As shown by a crystal structure determination with the 4-bromo-phenyl derivative (3), the Ga—Ga bond is bridged by both carboxylato groups in a chelating manner. The Ga—Ga distance is shortened to 238.5(2) pm (1: 254.1(1) pm) and the coordination number of the Ga atoms increased to four.
    Additional Material: 1 Ill.
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    URL: http://dx.doi.org/10.1002/cber.19961291204
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  • 196
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    The Mechanism of the Double Bond Cleavage in the Titanium Zeolite-catalyzed Oxidation of α-Methylstyrene by Hydrogen Peroxide: the β-Hydroperoxy Alcohol as Intermediate (1996)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 129 (1996), S. 1453-1455 
    Details
    ISSN: 0009-2940
    Keywords: Zeolites ; Titanium ; Epoxidation ; Double bond cleavage ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: It is unequivocally shown that acetophenone, an oxidation product in the titanium zeolite-catalyzed oxidation of α-methylstyrene, derives from 2-hydroperoxy-2-phenyl-1-propanol as intermediate, which was detected and isolated in this reaction for the first time.
    Additional Material: 2 Tab.
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    URL: http://dx.doi.org/10.1002/cber.19961291209
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  • 197
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    Synthesis and Substituent Interactions of Tricarbonylchromium-complexed Arylalkynylbenzenes  -  Novel Organometallic Push-pull ChromophoresDedicated to Prof. Dr. Rudolf Gompper on the occasion of his 70th birthday. (1996)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 129 (1996), S. 1433-1440 
    Details
    ISSN: 0009-2940
    Keywords: Arene complexes ; Chromium compounds ; Substituent effects ; Push-pull chromophores ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The tricarbonylchromium complexes chlorobenzene 1 reacts with terminal alkynes 2 through a palladium-copper-catalyzed coupling to give a variety of Cr(CO)3-complexed phenylethynyl arenes, heteroarenes and ferrocene 3 in good to excellent yield. Due to the electron-withdrawing nature of the Cr(CO)3 group these novel complexes can be regarded as organometallic push-pull chromophores. Analogously, the corresponding free ligands 4 (phenylethynyl arenes, heteroarenes and ferrocene) were synthesized by coupling iodobenzene and 2. The crystal structure analysis of the singly Cr(CO)3-complexed tolane 3e reveals a strong deviation from coplanarity of both phenyl rings by an angle of 50.9(2)° presumably due to crystal packing. Correlations are established between selected substituent parameters (σP, σI, σR, σP+ and Δπ) and the carbonyl carbon resonances in the 13C-NMR spectra for the complexes 3. The overall electronic substituent effect is transmitted to the carbonyl groups by both mesomeric and inductive mechanisms. The push-pull complexes 3 display relatively small negative solvochromicities of longest wavelength absorption band (MLCT band).
    Additional Material: 3 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19961291206
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  • 198
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    Mass Spectrometric Study of [Fe,C3,H6,O]+ Isomers Relevant in the Gas-phase Oxidation of Hydrocarbons by “Bare” FeO+ (1996)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 129 (1996), S. 1463-1474 
    Details
    ISSN: 0009-2940
    Keywords: Structure determination ; Mass spectrometry ; Oxidation processes ; Ion-molecule reactions ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The structures and energetics of [Fe,C3,H6,O]+ isomers are probed by mass spectrometric means. The complexes Fe-(CH3COCH3)+, Fe(CH3CH2CHO)+, Fe(CH3OCH=CH2)+, Fe(CH2O)(C2H4)+, c-(FeOCH2CH2CH2)+, Fe(CH2=CH-CH2OH)+, and Fe(OH)(C3H5)+ can be distinguished by comparing their reactivity toward benzene and their collision-induced dissociation mass spectra, respectively. These findings are used to interpret the formation of [Fe,C3,H6,O]+ in oxidation reactions of hydrocarbons by the highly reactive FeO+ cation. For example, in the reactions of FeO+ with norbornane and pentanol Fe(OH)(C3H5)+ is produced, while the reaction of FeO+ with norbornane to yield [Fe,C3,H6,O]+ is one of the rare cases of initial C—C bond activation by a “bare” transition-metal oxide. The reaction of FeO+ with propene involves formation of metalla oxetanes as primary products. In general, “bare” FeO+ is not selective and allylic C—H bond activation of propene competes efficiently, thus pointing to a potentially rich chemistry.
    Additional Material: 4 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19961291211
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  • 199
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    Steroids as Chiral Ligands: Different Molecular and Crystal Structures of Copper(II) Complexes of Mono- and Dideprotonated 16β-Salicylideneimino-17β-hydroxy-3-methoxyestra-1,3,5(10)-triene (1996)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 129 (1996), S. 1497-1501 
    Details
    ISSN: 0009-2940
    Keywords: Steroids ; Chiral amino alcohols ; Copper(II) salicylideneimine complexes ; X-ray analysis ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The steroidal 16β-salicylideneimino-17β-hydroxy compound 1, synthesized from the corresponding 16β, 17β-amino alcohol, served as a new tridentate chiral ligand for Cu2+-complexation. The X-ray data for 1 and for two dimeric copper complexes 2 and 3 are presented and discussed. Using copper(II) acetate for complexation, dideprotonation of 1 is observed. The neutral complex 2 obtained is characterized by a central planar four-membered copper - oxygen ring. The cycloaliphatic 17β-oxygen anions are bridging atoms; the copper ions are tetracoordinated. Reaction of 1 with copper(II) perchlorate gave only monodeprotonation of the phenolic groups. These oxygen anions are now the bridging atoms; furthermore the two copper ions are bridged by a perchlorate anion. Thus the central four-membered ring is folded (22°), and the copper ions are hexacoordinated (binding of a molecule of water). The crystal lattices of 2 and 3 are also quite different.
    Additional Material: 5 Ill.
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    URL: http://dx.doi.org/10.1002/cber.19961291216
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    Stabilization of a Planar-tetracoordinate Carbon Center in an Organometallic Complex Containing Both a Zirconocene and a Hafnocene Moiety (1996)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 129 (1996), S. 1-3 
    Details
    ISSN: 0009-2940
    Keywords: Planar-tetracoordinate carbon atoms ; Metallocene cations methyl ; Metallocene complexes alkynyl group-4 ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The methylhafnocene cation 2a reacts with bispropynylzirco-nocene to give a single regioisomeric planar-tetracoordinate carbon compound (4a) that contains the hafnium atom singly-bonded and the zirconium center η2-coordinated to the bridging μ-(η1-C:η2-C,C-2-butyne) ligand. However, the reaction between the methylzirconocene cation 2b with bis(phenylacetylide)hafnocene (3b) gives the pure regioiso-mer 4b with an opposite relative arrangement of the two group 4 transition metals (the methyl is at the planar-tetra-coordinate carbon atom C2). Complex 4a was characterized by an X-ray crystal structure analysis.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19961290102
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