SYNTHESIS OF TITANIUM COMPLEXES THAT CONTAIN TRIAMIDO-AMINE LIGANDS

We report the synthesis of a variety of titanium complexes that contai n (Et(3)SiNCH(2)CH(2))(3)N, (C6F5NCH2CH2)(3)N, or (Me(3)SiNCH(2)CH(2)C H(2))(3)N Ligands. Complexes in the first category include [(Et(3)SiNC H(2)CH(2))(3)N]TiCl, [(Et(3)SiNCH(2)CH(2))(3)N]Ti(OTf), and [(Et(3)SiN CH(2)CH(2))(3)N]Ti-(t-Bu). Complexes in the second category include [( C6F5NCH2CH2)(3)N]TiX (X = Cl, Br, I, OTf) and [(C6F5NCH2CH2)(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]TiCH3. In an X-r ay study [(Me(3)-SiNCH2CH2CH2)(3)N]TiCl was shown to contain a coordin ated amino nitrogen and TiN2C3 rings that were puckered in a pseudocyc lohexane chair form. The TiN2C3 rings are proposed to ''flip'' via dis sociation of the amino nitrogen donor in the methyl complex, but the f lipping 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 me tal.