PCP Pincer Complexes of Titanium in the +3 and +4 Oxidation States.

Ti(IV) and Ti(III) complexes using the tBu PCP ligand have been synthesized ( tBu PCP = C 6 H 3 -2,6-(CH 2 P t Bu 2 ) 2 ). The [ tBu PCP]Li synthon can be reacted with TiCl 4 (THF) 2 to form ( tBu PCP)TiCl 3 ( 1 ) in limited yields due to significant reduction of the titanium synthon. The Ti(III) complex ( tBu PCP)TiCl 2 ( 2 ) has been further characterized. This can have half an equivalent of halide abstracted to form [{( tBu PCP)TiCl} 2 {μ-Cl}][B(C 6 F 5 ) 4 ] ( 3 ) and can also be methylated, forming ( tBu PCP)TiMe 2 ( 4 ). All the Ti(III) complexes have been characterized using EPR and X-ray crystallography, giving insight into their electronic structures, which are further supported by DFT calculations.