On the reaction of bis(t-butylamino)dimethylsilane with titanium tetrachloride.: Crystal structures of the imido complex [TiCl2(N-CMe3)(H2N-CMe3)(CH3CN)]2 and of the ketimido complex [TiCl3{NC(Me)N(H)CMe3}(CH3CN)2]

The reaction of bis(t-butylamino)dimethylsilane with titanium tetrachloride in dichloromethane solution leads to a mixture of compounds from which the imido complex (H3N CMe3)(2) [TiCl3(N-CMe3)](2) (1) and by extraction of the residue with acetonitrile the imido complex [TiCl2 (N-CMe3) (H2N-CMe3)(CH3CN)](2) (2) can be isolated. 1 reacts with acetonitrile to give the ketimido complex [TiCl3 {NC(Me)N(H)CMe3}(CH3CN)(2)] (3). According to crystal structure determinations 2 consists of centrosymmetric dimeric molecules containing TiCl2Ti bridges, the N-CMe32- ligands being in equatorial positions with TiN bond lengths of 168.8(4) pm which corresponds to double bonds. In the monomeric complex 3 the chloro ligands are in meridional positions of the distorted octahedrally coordinated titanium atom with a TiN bond length of 175.7(2) pm of the ketimido ligand.