FORMATION OF ORGANOSILICON COMPOUNDS .112. THE INFLUENCE OF REACTION CONDITIONS ON THE REACTION OF (CL3SI)2CCL2 WITH SILICON - THE STRUCTURES OF CHLOROSILYL)-2,3,5,6-TETRASILABICYCLO[2.1.1]HEXANE AND 1,1,3,4,6,6-HEXAKIS(TRICHLOROSILYL)HEXATETRAENE

While reactions of (Cl3Si)2CC12 1 with Si(Cu) in a fluid bed at 320-de grees-C exclusively yield products by silylation of the CC12 group in 1 does the reaction in a stirred bed preferrably give rize to chlorosi lanes 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 dehalogenati on at carbon produces 3, 4 and 11. In the reaction of 1 with CaSi2 no additional Si-C bonds are formed, exclusively chlorosilanes with multi ple C-C bonds as 3, 4 and 10 were found besides of SiCl4. The bicyclo[ 2. 1. 1]hexane 6 (Tab. 1) crystallizes monoclinically in the space gro up C2/c (no. 15) with a = 1557.8, b = 857.4, c = 1 727.3 pm, beta = 10 4.34-degrees und Z = 4 molecules per unit cell; the hexatetraene 10 (T ab. 1) crystallizes monoclinically in the space group C2/m (no. 12) wi th a = 1189.6, b = 1433.8, c = 983.5 pm, beta = 98.75-degrees pm, and Z = 2 molecules per unit cell. The skeleton of 6 is a system of high b ond stress with 2-C2 symmetry. The strongly folded (138.8-degrees) fou r-membered ring (sum of angles = 344.2-degrees) and the presence of bo th 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 length s in the bicyclic compound were found to be dBAR(Si-C) = 190.9 pm and dBAR(Si-C) = 185.1 pm for exo- and endocyclic bonds, respectively. The skeleton of 10 is of the symmetry 2/m-C2h. The six-membered chain is plane. The central C-C single bond lenght and the mean distance of the cumulated double bonds are 148.6 pm and 130.5 pm, respectively.