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  • 1
    Electronic Resource
    Electronic Resource
    Bis[tris(trimethylsilyl)methyl]diselenid: Ein ungewöhnliches Dichalkogenid mit sterisch erzwungener trans-C2h-Konformation (1990)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 123 (1990), S. 2325-2327 
    Details
    ISSN: 0009-2940
    Keywords: Diselenide, torsion angle/NMR, 77Se/Selenenyl halide ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Bis[tris(trimethylsilyl)methyl] Diselenide: An Unusual Diselenide with Sterically Enforced trans-C2h ConformationDeselenation of bis[tris(trimethylsilyl)methyl] triselenide (1) with copper occurs with formation of bis[tris(trimethylsilyl)-methyl] diselenide (2) and minor amounts of 3,3,5,5-tetrakis(trimethylsilyl)-1,2,4-triselenolane (3). The structures of 2 and 3 have been studied by multinuclear NMR spectroscopy and by X-ray crystallography. The C—Se—Se—C moiety of 2 adopts an unusual antiperiplanar conformation. Cleavage of the Se — Se bond by iodine providing iodo[tris(trimethylsilyl)-methyl]selane (5) is complete with 2, but reversible with 1.
    Additional Material: 2 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19901231215
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  • 2
    Electronic Resource
    Electronic Resource
    Lithium-(2,4,6-tri-tert-butylphenylselenid); Erzeugung, Struktur und Reaktionen unter Knüpfung von Se -P-, Se - C-, Se - Si-, Se - Sn- und Se - Au-Bindungen (1991)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 124 (1991), S. 1315-1320 
    Details
    ISSN: 0009-2940
    Keywords: Chalcogen-chalcogen bonds ; Selenium ; Selenide (2,4,6-tri-tert-butylphenyl)- ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Properties of Chalcogen-Chalcogen Bonds, XV1). - Lithium 2,4,6-Tri-tert-butylphenylselenide: Synthesis, Structure, and Reactions with Formation of Se - P, Se - C, Se - Si, Se - Sn, and Se - Au BondsBis(2,4,6-tri-tert-butylphenyl)diselenide (1) is reduced by lithium triethylhydridoborate to give lithium 2,4,6-tri-tert-butyl-phenylselenide (2) in high yield. 2 crystallizes with three molecules of tetrahydrofuran coordinated to lithium ([2(THF)3] ≡ 2a, space group P&1macr; Z =4). The monomeric compound 2a contains four-coordinate lithium bonded to two-coordinate selenium. 2 (LiSeR) reacts with the nonmetal and metal halides tBu2PCl, CH2Cl2, Me3SiCl, Me3SnCl, and Ph3PAuCl to give tBu2PSeR (3), RSeCH2Cl (4), (RSe)2CH2 (5), Me3SiSeR (6), Me3SnSeR (7), and the novel gold(I) selenophenolate derivative Ph3PAuSeR (8)(R = 2,4,6-tri-tert-butylphenyl).
    Additional Material: 1 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19911240602
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  • 3
    Electronic Resource
    Electronic Resource
    Verbindungen des Germaniums und Zinns, 10[1] Thermolyse eines Cyclotristannans: Stannylen- versus Distannen-Reaktionen (1992)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 125 (1992), S. 563-566 
    Details
    ISSN: 0009-2940
    Keywords: Stannylene, bis(2,4,6-triisopropylphenyl)- ; Distannene, tetrakis(2,4,6-triisopropylphenyl)- ; 1,2-Distannacyclobutene derivative ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Compounds of Germanium and Tin, 10[1].  -  Thermolysis of a Cyclotristannane: Stannylene versus Distannene ReactionsHexakis(2,4,6-triisopropylphenyl)cyclotristannane (1), first described by Masamune and Sita, is easily accessible by treatment of tin(II) chloride with 2,4,6-triisopropylphenylmagnesium bromide. The equilibrium between 1 and its cleavage products bis(2,4,6-triisopropylphenyl)stannylene (2) and tetrakis(2,4,6-triisopropylphenyl)distannene (3) in toluene has been followed by 119Sn-NMR spectroscopy at elevated temperatures. Stannylene 2 can be trapped by open-chain or cyclic diketones as well as by 1,3-dienes. Reaction of 3 with phenylacetylene proceeds in a [2 + 2] fashion to provide the 1,2-distannacyclobutene derivative 5 whose structure was confirmed by X-ray crystallography.
    Additional Material: 1 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19921250306
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  • 4
    Electronic Resource
    Electronic Resource
    Spaltung sperriger Diarylditelluride mit Brom und Iod[1]; Strukturbestimmung an Et4N+ 2,4,6-(i-C3H7)3C6H2TeI-2 (1992)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 125 (1992), S. 761-766 
    Details
    ISSN: 0009-2940
    Keywords: Tellurium compounds ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Cleavage of Bulky Diaryl Ditellurides with Bromine and Iodine; Crystal Structure of Et4N+ 2,4,6-(i-C3H7)3C6H2TeI-2Bis(2,4,6-triisopropylphenyl) ditelluride (1a), obtained from 2,4,6-triisopropylphenylmagnesium bromide with tellurium followed by oxidation with oxygen, and bis(2,4,6-tri-tert-butylphenyl) ditelluride (1b) react with equimolar amounts of bromine and iodine to provide new monomeric arenetellurenyl halides 2,4,6-R3C6H2TeX (2a, b, 3a, b: R = i-C3H7, t-C4H9; X = Br, I). Both tellurenyl iodides are thermally more stable than the corresponding bromides. Green 2,4,6-(i-C3H7)3C6H2TeI (3a) reacts with Et4N+I- to give the stable, red adduct Et4N+ 2,4,6-(i-C3H7)3C6H2TeI-2 (4a). An X-ray crystal structure determination of 4a revealed a T-shaped structure of the hypervalent aryldiiodotellurate(II) anion. Iodide-ion transfer between aryldiiodotellurate(II) and arenetellurenyl iodide is a fast process (1H-NMR time scale). 125Te-NMR data of this anion and of tellurenyl halides are compared with those of the ditellurides and of lithium benzenetellurolates (LiTeR·(THF)x).
    Additional Material: 3 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19921250402
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  • 5
    Electronic Resource
    Electronic Resource
    Siliciumverbindungen mit starken intramolekularen sterischen Wechselwirkungen, 47. Trisilacyclobutanimine (1992)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 125 (1992), S. 1043-1046 
    Details
    ISSN: 0009-2940
    Keywords: Trisilacyclobutanimines ; Cyclotrisilane, hexa-tert-butyl- ; Isocyanide insertion reactions ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Silicon Compounds with Strong Intramolecular Steric Interactions, 47[1]. - TrisilacyclobutaniminesTreatment of hexa-tert-butylcyclotrisilane (4) with aryl isocyanides leads to the trisilacyclobutanimines 5-8. Reaction of the 1,4-diisocyanobenzene derivative 7 with two molecules of 4 leads to the double insertion product 9, the X-ray structure analysis of which shows the Si3CN framework atoms to be almost exactly coplanar. The planes of the two four-membered rings are strictly parallel whereas the linking phenylene group forms a 71.67° angle with these planes. The most striking features of these and of related compounds are their dark colours with longest wavelength absorptions between 500 and 540 nm.
    Additional Material: 1 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19921250510
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  • 6
    Electronic Resource
    Electronic Resource
    Stereoselectivity of the Transfer of Hydrogen Atoms to Cyclic Alkyl Radicals (1994)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 127 (1994), S. 1069-1073 
    Details
    ISSN: 0009-2940
    Keywords: Free-radical additions ; Alkyl radicals ; Stereoselectivity ; Hydrogen transfer ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The addition of cyclohexane to alkylmaleic anhydrides 1a-f via cyclic radicals 2a-f gave a mixture of (Z)- and (E)-2,3-dialkylsuccinic anhydrides 3a-f. The stereoselectivity of the hydrogen transfer from cyclohexane to radicals 2a-d was measured in the temperature range of 200-260°C, and the relative activation parameters of the formation of (Z)- and (E)-3 were determined. The stereoselectivity of the hydrogen transfer from cyclohexylmercuric hydride at 25°C was measured as well. The results are rationalized assuming steric interactions in the transition state of H donor and β substituent and of α and β substituent, respectively. An X-ray structure analysis of the highly strained addition product (Z)-3d was performed.
    Additional Material: 3 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19941270616
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  • 7
    Electronic Resource
    Electronic Resource
    Synthese und Molekülstruktur zweier 1-Sila-3-alanata-cyclobutan-Derivate mit AlC2Si-Heterozyklus (1994)
    Weinheim : Wiley-Blackwell
    Zeitschrift für anorganische Chemie 620 (1994), S. 1619-1626 
    Details
    ISSN: 0044-2313
    Keywords: C—H acidic aluminium organyls ; deprotonation of bis(trimethylsilyl)methyl groups ; AlC2Si heterocycles ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Synthesis and Molecular Structure of Two 1-Sila-3-alanata-cyclobutane Derivatives with Four-membered AlC2Si-HeterocyclesThe C—H acidic bis(trimethylsilyl)methyl compounds Me3C—AlR2 und Me3C—CH2—AlR2 (R — CH(SiMe3)2) are deprotonated by treatment with the sterically high shielded base LiCH(SiMe3)2 in the presence of 1,3,5-trimethylhexahydrotriazinane. The deprotonation occurs at a methyl group of one of the element-organic substituents, and the formed carbanions are stabilized by coordination to the unsaturated Al atoms yielding four-membered heterocycles. Both products were characterized by a crystal structure determination each showing bent ring systems.
    Notes: Die C—H-aciden Bis(trimethylsilyl)methyl-Verbindungen Me3C—AlR2 und Me3C—CH2—AlR2 (R — CH(SiMe3)2) reagieren mit der sterisch sehr hoch abgeschirmten Base LiCH(SiMe3)2 in Gegenwart von 1,3,5-Trimethylhexahydrotriazinan unter Deprotonierung einer Methylgruppe des elementorganischen Substituenten; die dabei gebildeten Carbanionen stabilisieren sich durch eine Wechselwirkung zu dem koordinativ ungesättigten Al-Atom unter Ausbildung von viergliedrigen AlC2Si-Heterozyklen. Beide Produkte wurden durch eine Kristallstrukturbestimmung charakterisiert, die jeweils ein nicht-planares Ringsystem ergab.
    Additional Material: 5 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/zaac.19946200921
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