Reductions of β-Diketiminato−Titanium(III) Complexes

Abstract

The reductions of (Nacnac)Ti(III) complexes (Nacnac = (HC(CMeNC 6 H 3 ( i -Pr) 2 ) 2 ) are examined. Treatment of (Nacnac)TiCl 2 with K/Na alloy in the presence of CH 2 (PPh 2 ) 2 afforded the dark red product [K(C(Me)CHC(Me)NAr)Ti(NAr)(μ-H)] 2 ( 2 ). This Ti(III)-imido-hydride complex is a product of Nacnac ligand cleavage. The Ti(III) species (Nacnac)CpTiCl ( 3 ) and (Nacnac)(C 5 Me 4 H)TiCl ( 4 ) were prepared and characterized. While compound 3 was readily alkylated with n- BuLi to give (Nacnac)CpTiBu ( 5 ), reduction of 3 with Na/K gave the dinitrogen complex ((Nacnac)CpTi) 2 (μ-η 2 -N 2 ) ( 6 ). In contrast, treatment of 4 with t- BuLi or n- BuLi or Na/K amalgam afforded the ligand cleavage product (C 5 Me 4 H)[(ArNC(Me)CHC(Me)]Ti(NAr) ( 7 ). Compounds 2 − 7 are crystallographically characterized. The effects of the nature of the ancillary ligands on the course of these reactions are considered.