μ-Benzyl and μ-Chloro Dinuclear Cationic Titanium Compounds

The reaction of [Ti(η5-C5H4SiMe2-κO)(CH2Ph)2]2 with the Lewis acid B(C6F5)3 in toluene at room temperature affords the new dinuclear monocationic species [{Ti(η5-C5H4SiMe2-κO)}2(CH2Ph)3]+[PhCH2B(C6F5)3]- (1). This compound is thermally unstable and decomposes in aromatic solvents to give the paramagnetic mixed-valence species [{Ti(η5-C5H4SiMe2-κO)}(CH2Ph)]2+Q- (Q- = [PhCH2B(C6F5)3]- (2), [B(C6F5)4]- (3)). In chlorinated solvents 1 affords the μ-chloro complexes [{Ti(η5-C5H4SiMe2-κO)(CH2Ph)}2(μ-Cl)]+Q- (Q- = [PhCH2B(C6F5)3]- (4), [B(C6F5)4]- (5)). Different isomers of 1 are observed, depending on the temperature, as deduced by variable-temperature NMR spectroscopic studies.