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Institute: search.filters.UBSInstitut.Institut für Organische ChemieAuthor: search.filters.author.Becker, Gerd

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    Calcium-bis{[tris(trimethylsilyl)silyl]tellanid} · 4 THF : Synthese, spektroskopische Charakterisierung und Struktur
    (1992) Becker, Gerd; Klinkhammer, Karl Wilhelm; Schwarz, Wolfgang; Westerhausen, Matthias; Hildenbrand, Thomas
    Calcium bis {[tris(trimethylsilyl)silyl]tellanide} · 4THF is obtained by metallation of tris(trimethylsilyl)silyl)tellane using dimeric calcium bis[bis(trimethylsilyl)amide] in toluene, followed by recrystallisation from tetrahydrofuran. The compound is characterized by a remarkable highfield shift of the 1 2.5 Te{1H}-NMR resonance (-2204 ppm vs. Me2Te). The X-ray structure determination (triclinie, pI; Z = 1; a = 1042.6(2), b = 995.7(2), c = 1379.6(3) pm; α= 90.06(2), β= 92.76(2),), γ= 94.03(2)° at -100 "C) shows a distorted octahedral coordination sphere of the calcium atom (Ca-Te 319; Ca-O 236 and 241 pm). The two [tris(trimetbylsilyl)silyl}-tellanide ligands are in a trans position; the angle Ca-Te-Si is widened to 129°.
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    Bis[bis(trimethylsilyl)methyl]galliumbromid und monomeres {Bis[bis(trimethylsilyl)methyl]gallium}tris(trimethylsilyl)silyl]tellurid [(Me3Si)2CH]2Ga–TeSi(SiMe3)3
    (1992) Uhl, Werner; Layh, Marcus; Becker, Gerd; Klinkhammer, Karl Wilhelm; Hildenbrand, Thomas
    Bis[bis(trimethylsilyl)methyl]gallium bromide GaBr[CH(SiMe3)2]2 (4), prepared from Ga2Br4 · 2 dioxane and bis(trimethylsilyl)-methyllithium in the molar ratio of 1:3, reacts with the sterically high-shielded lithium tris(trimethylsilyl)silyltelluride · DME to yield [(Me3Si)2CH]2Ga–TeSi(SiMe3)3 (5). 5 can also be synthesized by a metathetic reaction between tetrakis-[bis(trimethylsilyl)methyl]digallium(4) and bis[tris(trimethylsilyl)silyl]ditellane in toluene at 100°C. A crystal structure determination shows the compound to be monomeric in the solid state and the atoms of the central C2Ga–TeSi moiety to lie in the mirror plane of the molecule. The short Ga–Te distance of 253.5(1) pm as well as a hindered rotation (ΔErot ≈ 50 kJ · mol-1) as detected by NMR measurements might be interpreted in terms of a π interaction between gallium and tellurium.