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  • 1
    Electronic Resource
    Electronic Resource
    Synthese, Strukturen und Eigenschaften der Cyclothiaselenazenium-Kationen [Se2N2S]22+, [XSe2N2S]+, [Se2N2S]2+, [S3SeN5]+ sowie Cl2Se2N2S und SeSN2 ṁ TiCl4 (1991)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 124 (1991), S. 1895-1906 
    Details
    ISSN: 0009-2940
    Keywords: Selane, bis(sulfinylamido)- ; Diselane, trimethylsilyl- ; 1,3,4,2,5-Thiadiselenadiazolium ; 1,3,2,4-Thiaselenadiazete-Titanium tetrachloride ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Synthesis, Structures, and Properties of Cyclothiaselenazenium Cations [[Se2N2S]22+, [XSe2N2S]+, [Se2N2S]2+, [S3SeN5]+as well as Cl2Se2N2S and SeSN2 and SeSN2 ṁ TiCl4Bis(sulfinylamino)selane (1), prepared from Se2Cl2 and (CH3)3SiNSO, reacts with Lewis acids such as MF5 (M = As, Sb, Nb) and BF3 to form bis(1,3,4,2,5-thiadiselenadiazolium) cations (3) with counter anions AsF-6 (3a), SbF-6 (3b), NbF-6 (3c), BF-4 (3d). Treatment of Se2Cl2 with LiN[Si(CH3)3]2 leads to [(CH3)3Si]2NSexN[Si(CH3)3]2 (x = 1, 2a: 2, 2b). From 2a and 2a and SeCl4 explosive Se4N4 is obtained. Chlorination of 3a and 3c gives [ClSe2N2S]+[MF6]- (M = As, 4a, and Nb, 4c). Analogous bromination of 3a provides [BrSe2N2S]+ [AsF6]- (4b). This type of chlorinated five-membered rings is also obtained directly from 1 and SbCl5 and PCl5 or SeCl4. The products isolated are [ClSe2N2S]+ [SbCl6]- (4d) and [ClSe2N2S]+Cl- (4e). - A covalent species 5, isomeric to 4e, is obtained from 1 and POCl3, and a four-membered ring SeSN2 ṁ TiCl4 (6) from 1 and TiCl4. When 3a or 1 is treated with a two- or threefold excess of AsF5 the stable dication [Se2N2S]2+ (7) is formed. It arises also from 4e and AgAsF6. Attempts to replace TiCl4 in 6 by AsF5 lead to [SeS3N5]+ [AsF6]- (8) with a bicyclic structure for the cation. X-ray structure analyses for 1, 4c, 4d, 4e, 5, and 8 are performed.
    Additional Material: 7 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19911240903
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  • 2
    Electronic Resource
    Electronic Resource
    Organische Synthesen mit Übergangsmetallkomplexen, 46. Alkenylcarben-Chrom- und -Wolframkomplexe; Protonierung und Aktivierung durch Elektronen-ziehende Substituenten (1990)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 123 (1990), S. 1847-1852 
    Details
    ISSN: 0009-2940
    Keywords: Carbene complexes of chromium and tungsten ; Alkenylcarbene complexes, protonation of ; β-(Acylamino)alkenyl complexes of chromium ; Activated aminocarbene complexes ; 1-Metalla-1,3-dienes ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Organic Syntheses via Transition Metal Complexes, 46.  -  Alkenylcarbene Chromium and Tungsten Complexes; Proton Addition and Activation by Electron-Withdrawing SubstituentsAlkenylcarbene complexes LnM=C(OEt)-CH=C(R)NMe2[1, LnM = Cr(CO)5, W(CO)5; R = H, CH3, C6H5] add HBF4 in ether to give novel cationic carbene complexes [Ln M=C(OEt)-CH2-C(R)=NMe2]BF4 (3) by protonation at C-2 of the =C-C=C ligand. The addition of HBF4 to 7 leads to the formation of the cyclic carbene complexes 8. Structures of 3 and 8 are assigned spectroscopically. X-ray data are reported for 8a. Protonation of 1 and 7 results in a strong deshielding of the carbene carbon atoms, which parallels an increase of reactivity at the M=C bonds. An activation of the M=C bond has also been achieved by electron-withdrawing substituents like N-acyl groups. We report on the first synthesis of [β-(acylamino)-alkenyl]carbene complexes 13, which are more reactive than β-(aminoalkenyl)carbene complexes 7.
    Additional Material: 2 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19901230916
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  • 3
    Electronic Resource
    Electronic Resource
    Synthese, Struktur und Reaktivität eines Stanna(II)-nickela(II)-cyclobuten-Komplexes (1992)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 125 (1992), S. 103-106 
    Details
    ISSN: 0009-2940
    Keywords: Alkynes ; Nickel complexes ; Stannenes ; Metallacycloalkenes ; Kinetic and thermodynamic reaction control ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Synthesis, Structure, and Reactivity of a Stanna(II)-nickela(III)-cyclobutene KomplexesThe (ethyne)nickel(0) complex (iPr2PC2H4PiPr2)Ni(C2H2) (1) reacts with the stannene Sn[CH(SiMe3)2]2 below -30°C to yield the stanna(II)-nickela(II)-cyclobutene complex (iPr2PC2H4PiPr2)YYNiCH=YYCHSn[CH(SiMe3)2]2 (2; 83%) as the kinetically controlled product; 2 has been characterized by IR and NMR spectroscopy and an X-ray crystal-structure determination. The latter shows the central four-membered ring to be planar with a long Ni - Sn bond [2.626(1) Å]. According to the temperature-dependent NMR spectra, 2 dissociates reversibly in solution to the starting components. The synthesis reaction thus represents an equilibrium as long as the temperature is below 20°C. These observations indicate that the structural lability of the stanna(II)-nickela(II)-cyclobutene moiety is associated with the weakness of the Ni - Sn bond. The bonding situation in 2 is best described as an “inner complex” in which a stannyl anion is coordinated to a nickel(II) cation. An ethereal solution of 2 undergoes an oxidative addition of one ethyne C - H bond to the stannene at 20°C to give the Ni(0)/Sn(IV) complex iPr2PC2H4PiPr2)Ni({η2-HC≡CSn(H)[CH(SiMe3)2]2} (3) as the thermodynamically controlled product. Reaction of 3 with CO liberates the new alkyne ligand.
    Additional Material: 1 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19921250117
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  • 4
    Electronic Resource
    Electronic Resource
    Metallacyclobutene aus η2-Cyclopropen-Komplexen des Titanocens und Zirkonocens (1991)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 124 (1991), S. 2165-2170 
    Details
    ISSN: 0009-2940
    Keywords: Titanocene complexes ; Zirconocene complexes ; Cyclopropene complexes ; Metallacyclobutenes ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Metallacyclobutenes via η2-Cyclopropene Complexes of Titanocene and Zirconocene(η2-Cyclopropene)(trimethylposphane) complexes of titanocene (4, 5) and zirconocene (8) are obtained in good yields by the reaction of 1,2-diphenylcyclopropene (2) or 4,8-dioxaspiro[2.5]oct-1-ene (3) with bis(trimethylphosphane)titanocene (1) and (1-butene)(trimethylphosphane)zirconocene (7), respectively. In solution the new complexes 4 and 8 rearrange smoothly above room temperature to give the metallacyclobutene derivatives 6 and 9. All new compounds were characterized by spectroscopic methods (31P, 1H, 13C NMR), and the crystal structure of 9 was determined by an X-ray analysis.
    Additional Material: 1 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19911241004
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  • 5
    Electronic Resource
    Electronic Resource
    Eine einfache Synthese von dimetallischen Zirconium/Aluminium-Verbindungen mit planar-tetrakoordiniertem Kohlenstoff (1992)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 125 (1992), S. 1953-1956 
    Details
    ISSN: 0009-2940
    Keywords: Zirconium-aluminium dimetallic complexes ; Carbon, planar-tetracoordinate ; μ-Alkyne complexes ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: A Simple Synthesis of Dimetallic Zirconium/Aluminium Compounds Containing Planar-Tetracoordinate Carbon(η2-Alkyne)(trimethylphosphane)zirconium complexes [alkyne = cyclohexyne (3a) or diphenylacetylene (3b)] react with diisobutylaluminium hydride at room temperature by PMe3 cleavage and addition of H—Al(isobutyl)2 to the in situ-generated (η2-alkyne)ZrCp2 intermediate to give the dimetallic Zr,Al compounds 4. These thermodynamically stable complexes contain a planar-tetracoordinate carbon center whose uncommon coordination geometry is stabilized by a combination of the s̰-donor interaction with both electropositive metals and the π-conjugation of the Zr—C = C moiety.
    Additional Material: 2 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19921250823
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  • 6
    Electronic Resource
    Electronic Resource
    Kristallstruktur und Gasphasenuntersuchungen von lithiiertem Acetessigsäure-tert-butylesterHerrn Professor Günther Maier zum 60. Geburtstag gewidmet. (1992)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 125 (1992), S. 2779-2782 
    Details
    ISSN: 0009-2940
    Keywords: Lithium enolate ; PE spectroscopy ; Mass spectrometry ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Crystal Structure and Gas-Phase Investigations of Lithiated tert-Butyl AcetoacetateThe lithium enolate 2, generated either by deprotonation of tert-butyl acetoacetate (1) or by pyrolysis of lithiated tert-butyl acetate (3) is crystallized from toluene. The X-ray diffraction analysis of unsolvatized 2 reveals a hexameric structure. Thereby, the central skeleton is formed by two Li-O six-membered rings, and the carbonyl group of the ester moiety serves to complete the fourfold coordination of the lithium atom. The thermal stability of 2 enables the very first mass spectrometric and photoelectron spectroscopic investigation of a lithium enolate. The lithium compound 2 forms aggregates even in the gas phase. The first vertical ionization energy of 2 is found to be significantly lower than those observed in the photoelectron spectra of both the enol ether 5 and the ester 1.
    Additional Material: 2 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19921251225
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  • 7
    Electronic Resource
    Electronic Resource
    Notizen / Notes [Li2(THF)4DAD] und [DAD  -  H][ZrCl5(THF)]: Neue Strukturvarianten phenylsubstituierter 1,4-Diaza-1,3-dien-Liganden (1993)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 126 (1993), S. 57-61 
    Details
    ISSN: 0009-2940
    Keywords: Lithium compounds ; Enediamide structure ; 1,4-Diaza-1,3-diene, protonated ; Hydrogen bond ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: [Li2(THF)4DAD] and [DAD  -  H][ZrCl5(THF)]: New Types of Phenyl-;Substituted 1,4-Diaza-1,3-diene LigandsTwo extreme situations in 1,4-diaza-1,3-diene (DAD) chemistry are described. Reaction of phenyl-substituted DAD 1a  -  c with lithium in the molecular ratio of 1:2 affords in high yield the extremely air-sensitive complexes [Li2(THF)4DAD] (2a  -  c). The structure of 2b has been determined by X-ray diffraction. Each of the Li+ ions is coordinated by the two terminal N atoms of the s-cis-configurated DAD dianion and by two molecules of THF. Protonation of ZrCl4 · DAD (3a) by HCl in THF gives the ionic complex [ZrCl5(THF)][DAD  -  H] (4), which contains a protonated [DAD  -  H]+ cation. The structure of the sterically crowded N = C  -  C = N skeleton of the [DAD  -  H]+ cation is not influenced by the positive charge and adopts the unusual Z-gauche-Z conformation.
    Additional Material: 2 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19931260110
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  • 8
    Electronic Resource
    Electronic Resource
    Reduktion von (Cyclobutadien)(cyclopentadienyl)- und (1,5-Cyclooctadien)- (cyclopentadienyl)nickel-Kationen (1990)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 123 (1990), S. 227-237 
    Details
    ISSN: 0009-2940
    Keywords: Nickel sandwich complex / Voltammetry, cyclic / Electrochemistry / Reductive dimerization / ESR spectra ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Reduction of (Cyclobutadiene)(cyclopentadienyl)- and (1,5-Cyclooctadiene)(cyclopentadienyl)nickel CationsCyclic voltammetry of the four cationic Ni sandwich complexes [Ni(C5R5)(C4R4')]+ (2: R = H, R' = Ph; 3: R = H, R' = Me; 4; R = Me, R' = Ph; 5: R = R' = Me) shows reversible one-electron reductions for the phenyl derivatives 2 and 4 and a peak pattern characteristic of reductive dimerization/oxidative monomerization for the methyl derivatives 3 and 5. The product of the reduction of 3 was isolated and characterized analytically and by an X-ray structure determination as the dimer 6 of 3, linked through cyclobutenyl rings, the first example for a dimerization of an electron-rich sandwich complex at a substituted C atom. EPR spectra of the neutral complexes 2 and 4 are compared to those of (1,5-cyclooctadiene)(cyclopentadienyl)nickel (7) and are interpreted in terms of a substantial static Jahn-Teller distortion.
    Additional Material: 4 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19901230202
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  • 9
    Electronic Resource
    Electronic Resource
    Pyrrole durch metallinduzierte [3 + 2]-Cycloaddition von 2-Azaallenyl-( = Iminocarben-)Komplexen unter Übertragung einer CNC-Einheit auf ein Alkin; ein Chromacyclopropen durch Cyclocarbonylierung eines 1-Aminoalkins (1990)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 123 (1990), S. 599-604 
    Details
    ISSN: 0009-2940
    Keywords: 2-Azaalienyl chromium complexes / Pyrroles by [3+2] cycloadditions of CNC units / Umpolung of nitrile ylides, metal-induced / 1-Aminoalkynes, cyclocarbonylation / Chromacyclopropene ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Organic Syntheses via Transition Metal Complexes, 40. - Pyrroles by Metal-Induced [3 + 21 Cycloadditions of 2-Aza-allenyl (= Iminocarbene) Complexes with Transfer of a CNC Unit to Alkynes; a Chromacyclopropene Complex by Cyclocarbonylation of a 1-AminoalkyneThe 2-azaallenyl (= iminocarbene) complex LnM⊖ - CR = N⊕ = CXR1 1a [LnM = Cr(C0)5 = OEt, R1 = Ph] adds to the polarized alkyne Et2N - C≡C-CH3 (3) to give a 2H-pyrrole complex 4 in a metal-induced [3+2] cycloaddition. On warming 4 yields the 2H-Pyrrole 5. Since the regiochemistry of the addition of the CNC unit is opposite to that of a nitile ylide, we consider 1 as an Umpolung equivalent (RC⊕ = N - C⊖XR1) of a nitrile ylide (RC⊕ = N - C⊖XR1). The 2H-pyrrole 5 is kinetically unstable and isomerizes smoothly to the 1H-pyrrole 7 under the influence of base by an intramolecular redox reaction. A novel (cyclopentadienyl)chromacyclopropene complex 8 resulting from a cyclocarbonylation of the iminoalkyne 3 is obtained as a minor side product. The structural data of 4 and 8 have been determined by X-ray analyses.
    Additional Material: 2 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19901230328
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  • 10
    Electronic Resource
    Electronic Resource
    Zur Lewis-Acidität von Nickel(0), XII. Dimethylaluminiumhydrid-Komplexe von Nickel(0) (1990)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 123 (1990), S. 1267-1273 
    Details
    ISSN: 0009-2940
    Keywords: Aluminium Hydride complexes ; Nickel(0) ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: On the Lewis Acidity of Nickel(0). XII. - Dimethylaluminium Hydride Complexes of Nickel(O)Ni(CDT) reacts with (1-azabicyclo[2.2.2]octane)dimethylaluminium hydride in pentane to form the yellow crystaline addition compound (C7H13N)(Me2AlH)Ni(CDT) (2c). In its crystal structure 2c exhibits a Ni-H-Al three-center bond. Displacement of the CDT ligand of 2c with ethene in pentane at 0°C yields light brown crystals of (C sb7H13N)(Me2AlH)Ni(C2H4)2 (4), which is also obtained from Ni(C2H4)3 and (C7H13N)-Me2AlH). Complex 4 is converted by CO at - 78°C into the colorless carbonyl complex (C7H13N)(Me2AlH)Ni(CO)3 (5). 2c and 4 may be considered as model compounds for intermediates of the nickel(0)-catalyzed hydroalumination reaction of alkenes.
    Additional Material: 1 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19901230609
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