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

Ti(IV) and Ti(III)
complexes using the tBuPCP ligand
have been synthesized (tBuPCP = C6H3-2,6-(CH2PtBu2)2). The
[tBuPCP]Li synthon can be reacted with TiCl4(THF)2 to form (tBuPCP)TiCl3 (1) in limited yields due to significant reduction of the titanium
synthon. The Ti(III) complex (tBuPCP)TiCl2 (2) has been further characterized. This can have half an equivalent
of halide abstracted to form [{(tBuPCP)TiCl}2{μ-Cl}][B(C6F5)4] (3) and can also be methylated, forming (tBuPCP)TiMe2 (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.