2 NEW TITANIUM COMPLEXES WITH N,N'-DIPHENYLFORMAMIDINIUM (DPHF-), TI(DPHF)3 AND TI2(MU-DPHF)2(DPHF)2(MU-NPH)2

The reduction of TiCl4 with 1 equiv. of sodium amalgam and addition of 3 equiv. of [PhNC(H)NPh]Li affords the titanium(III) compound Ti(DPhF)3 (1). The molecular symmetry of 1 is slightly distorted from D3. Interestingly, reduction of TiCl4 with 2 equiv. of HSn(n-Bu)3 and addition of 3 equiv. of [PhNC(H)NPh]Li does not produce a Ti(II) product, but rather an imido bridged compound, Ti2(mu-NPh)2(mu-DPhF)2(DPhF)2 (2), in which the imido ligand forms alternately short [1.789(2) angstrom] and long [2.068(2) angstrom] bonds to the Ti(IV) atoms. The process by which the NPh2- ligand is generated from the [DPhF]- ion has not yet been determined. However, it is clear that titanium atoms must be oxidized from +2 to +4 and that C-N bonds in the [DPhF]- ligand are cleaved. The crystal structures of both compounds are reported.