The formation and structures of the methyl-bridged complexes Cp∗TiMe2(μ-Me)B(C6F5)3 and [Cp∗TiMe2(μ-Me)TiMe2Cp∗][MeB(C6F5)3]

Abstract Reaction of the compound Cp ∗ TiMe 3 ( Cp ∗ = η 5 - penthamethylcyclopentadienyl ) with the potent Lewis acid B(C 6 F 5 0 3 results in methyl carbanion abstraction from the titanium and formation of the corresponding complex Cp ∗ TiMe 2 (μ-Me)B(C 5 F 5 ) 3 , in which a methyl group bridges the titanium and boron atoms. The isotopically labelled compounds Cp ∗ Ti(CH 2 D) 3 , Cp ∗ Ti(CH 2 D) 2 (μ-CH 2 D)B(C 6 F 5 ) 3 , Cp ∗ Ti( 13 CH 3 ) 3 , and Cp ∗ Ti( 13 CH 3 ) 2 (μ- 13 CH 3 )B(C 6 F 5 ) 3 have also been prepared to provide NMR probes of the possibility of α-agostic bonding in these compounds, and while the answer appears to be ‘no’, a caveat on the use of this type of experiment is proposed. The compounds Cp ∗ TiMe 3 and Cp ∗ TiMe 2 (μ-Me)B(C 6 F 5 ) 3 react further to form the novel but unstable methyl-bridged species [Cp ∗ TiMe 2 (μ-Me)TiMe 2 Cp ∗ ][MeB(C 6 F 5 ) 3 ], which has been characterized by 1 H and v 13 C( 1 H) NMR spectroscopy.