Synthesis of Titanium Complexes That Contain Triamido−Amine Ligands

We report the synthesis of a variety of titanium complexes that contain (Et 3 SiNCH 2 CH 2 ) 3 N, (C 6 F 5 NCH 2 CH 2 ) 3 N, or (Me 3 SiNCH 2 CH 2 CH 2 ) 3 N ligands. Complexes in the first category include [(Et 3 SiNCH 2 CH 2 ) 3 N]TiCl, [(Et 3 SiNCH 2 CH 2 ) 3 N]Ti(OTf), and [(Et 3 SiNCH 2 CH 2 ) 3 N]Ti( t -Bu). Complexes in the second category include [(C 6 F 5 NCH 2 CH 2 ) 3 N]TiX (X = Cl, Br, I, OTf) and [(C 6 F 5 NCH 2 CH 2 ) 3 N]TiR (R = Me, Et). Complexes in the third category include [(Me 3 SiNCH 2 CH 2 CH 2 ) 3 N]TiCl and [(Me 3 SiNCH 2 CH 2 CH 2 ) 3 N]TiCH 3 . In an X-ray study [(Me 3 SiNCH 2 CH 2 CH 2 ) 3 N]TiCl was shown to contain a coordinated amino nitrogen and TiN 2 C 3 rings that were puckered in a pseudocyclohexane chair form. The TiN 2 C 3 rings are proposed to “flip” via dissociation of the amino nitrogen donor in the methyl complex, but the flipping rate is slow on the NMR time scale in [(Me 3 SiNCH 2 CH 2 CH 2 ) 3 N]TiCl as a consequence of the greater electrophilicity of the metal.