Simple Synthesis of (Triphenylphosphoniomethylidene)(pentamethylcyclopentadienyl)titanium(II) Dichloride and Its Unexpected Reduction To Form a Trinuclear Titanium Cluster

The novel titanium phosphoniomethylidene complex [Cp*TiCl2(−CHPPh3)] (2; Cp* = η-C5Me5) was obtained via a transylidation reaction of Cp*TiCl3 (1) with 2 equiv of the phosphorus ylide Ph3PCH2. The trinuclear titanium(III) cluster [Cp*Ti(μ-Cl)Cl]3 (3) was formed through reduction of complex 2 with CO. Complexes 2 and 3 were structurally characterized by X-ray diffraction.