Fa. Cotton et Wa. Wojtczak, 2 NEW TITANIUM COMPLEXES WITH N,N'-DIPHENYLFORMAMIDINIUM (DPHF-), TI(DPHF)3 AND TI2(MU-DPHF)2(DPHF)2(MU-NPH)2, Polyhedron, 13(9), 1994, pp. 1337-1341
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. Int
erestingly, reduction of TiCl4 with 2 equiv. of HSn(n-Bu)3 and additio
n 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 oxid
ized from +2 to +4 and that C-N bonds in the [DPhF]- ligand are cleave
d. The crystal structures of both compounds are reported.