Molekül- und Kristallstruktur des 1,4-Bis[tris(tetrahydrofuran)lithium]-octaphenyltetrasilans |
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Authors: | G. Becker H.-M. Hartmann E. Hengge F. Schrank |
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Abstract: | Molecular and Crystal Structure of 1,4-Bis[tris(tetrahydrofuran)lithium]-octaphenyltetrasilane 1,4-Dilithium-octaphenyltetrasilane prepared from octaphenyl-cyclo-tetrasilane and lithium in tetrahydrofuran (THF) [4], can be isolated from tetrahydrofuran/n-pentane as an adduct with six molecules of tetrahydrofuran per formula unit. The orange-red compound crystallizes in the triclinic space group P1 {a = 1159.6(3); b = 1268.4(2); c = 1367.8(3) pm; α = 92,23(2)° β = 113.79(2)° γ = 111.62(2)° at ?5 ± 3°C; Z = 1}. An x-ray structure determination (Rw = 0.046) shows the existence of a centrosymmetric molecule with an extended planar Li? Si4? Li unit; either lithium atom is bound to silicon and to the oxygen atoms of three molecules of tetrahydrofuran. Characteristic bond lengths and angles are: Li? Si 271; Si? Si 241 and 243; Si? C 190 to 192 pm; Li? Si? Si 126°; Si? Si? Si 127°. 29Si and 7Li n.m.r. measurements at low temperatures indicate the presence of three different adducts. |
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