Chloro- and Alkyltitanium Complexes of a New Dianionic Ancillary Ligand: A Linked Amidinate-Amide

The lithium amidinate [Me3SiNC(Ph)N(CH2)3N(Me)SiMe3]Li(THF) (2), with a pendant methyl(trimethylsilyl)amine functionality, was prepared and found to react with [TiCl4(THF)2] to give the titanium amidinate−amide dichloride complex [η2,η1-Me3SiNC(Ph)N(CH2)3NMe]TiCl2 (3) by elimination of LiCl and Me3SiCl. The elimination of Me3SiCl from the cyclopentadienyl derivative Cp[η2-Me3SiNC(Ph)N(CH2)3N(SiMe3)Me]TiCl2 (5) to give Cp[η2,η1-Me3SiNC(Ph)N(CH2)3NMe]TiCl (4) is much less favorable, and was found to be readily reversible. Dialkyltitanium complexes [η2,η1-Me3SiNC(Ph)N(CH2)3NMe]Ti(CH2R)2 [R = Ph (6), SiMe3 (7)] were prepared, but could not be activated for catalytic ethene polymerization.