1.4-addition of 1.1.2.2-tetrachlorodimethyldisilane to 1.4-diaza-1.3-dienes, synthesis and molecular structure of 1.6-disila-2.5-diaza-1.1.6.6-tetrachloro-1.6-dimethyl-2.5-di-p-tolyl-3.4-diphenyl-hexa-3-ene

Article abstract of DOI:10.1016/S0022-328X(96)06823-4

Reaction of 1.1.2.2-tetrachlorodimethyldisilane (4) with 1.4-diazadienes like benzildianil (1), benzildi-p-tolil (2) and benzildi-p-anisil (3) leads to a 1.4-addition product of the disilane under cleavage of the Si-Si bond (1a, 2a, 3a). The structure of 2a was determined by X-ray crystallography (crystal data: monoclinic, P2₁/n, a = 14.661(4), b = 12.283(2), c = 17.564(5) A, β = 103.13°, Z = 4, R = 0.0585 for 5992 independent reflections). Surprisingly, 2a was found to be in the cis-configuration with almost C₂ symmetry and a torsion angle of only 13°. Owing to statistical disorder, some bond lengths are not in the expected range.