Bildung siliciumorganischer Verbindungen. 112. Über den Einfluß der Reaktionsbedingungen auf die Umsetzung von (Cl3Si)2CCl2 mit Silicium. Die Struktur von 2,2,3,3,5,5,6,6-Octachlor-1,4-bis(trichlorsilyl)-2,3,5,6-tetrasilabicyclo[2.1.1]hexan und 1,1,3,4,6,6-Hexakis(trichlorsilyl)hexatetraen

Formation of Organosilicon Compounds. 112. The Influence of Reaction Conditions on the Reaction of (Cl₃Si)₂CCl₂ with Silicon. The Structures of 2,2,3,3,5,5,6,6-Octachloro-1,4-bis(trichlorosilyl)-2,3,5,6-tetrasilabicyclo2.1.1]-hexane and 1,1,3,4,6,6-Hexakis(trichlorosilyl)hexatetraene While reactions of (Cl₃Si)₂CCl₂ 1 with Si(Cu) in a fluid bed at 320°C exclusively yield products by silylation of the CCl₂ group in 1 does the reaction in a stirred bed preferrably give rize to chlorosilanes containing C? C double and triple bonds. Compounds 5, 6, 7, 8 and 9 in Tab. 1 belong to the first group, whereas 3 and 4 belong to the second one. The reaction of 1 with elemental copper under dehalogenation at carbon produces 3, 4 and 11 . In the reaction of 1 with CaSi₂ no additional Si? C bonds are formed, exclusively chlorosilanes with multiple C? C bonds as 3, 4 and 10 were found besides of SiCl₄. The bicyclo2.1.1]hexane 6 (Tab. 1) crystallizes monoclinically in the space group C2/c (no. 15) with a = 1557.8, b = 857.4, c = 1727.3 pm, β = 104.34° und Z = 4 molecules per unit cell; the hexatetraene 10 (Tab. 1) crystallizes monoclinically in the space group C2/m (no. 12) with a = 1189.6, b = 1433.8, c = 983.5 pm, β = 98.75° pm, and Z = 2 molecules per unit cell. The skeleton of 6 is a system of high bond stress with 2-C₂ symmetry. The strongly folded (138.8°) four-membered ring (sum of angles = 344.2°) and the presence of both a Si? Si bond length of 238.2 pm and a Si? Si non-bonding distance of 255.1 pm are remarkable aspects of this feature. The mean bond lengths in the bicyclic compound were found to be d(Si? C) = 190.9 pm and d(Si? C) = 185.1 pm for exo- and endocyclic bonds, respectively. The skeleton of 10 is of the symmetry 2/m-C_2h. The six-membered chain is plane. The central C? C single bond length and the mean distance of the cumulated double bonds are 148.6 pm and 130.5 pm, respectively.