Mono- and bi-nuclear titanium imido complexes supported by aryloxide ligands: fine control by ortho substituents

Abstract

Reaction of the titanium imido complexes [Ti(NR)Cl₂(py)₃] (R = Bu^t, C₆H₃Me₂-2,6 or C₆H₃Prⁱ₂-2,6; py = pyridine) with 2 equivalents of lithium aryloxide Li[OC₆H₃R′₂-2,6] (R′ = Me, Prⁱ or Bu^t) afforded the mononuclear four- or five-co-ordinate or binuclear four-co-ordinate complexes [{Ti(NR)(OC₆H₃R′₂-2,6) ₂(py)_n}_m] (m = 1, n = 1 or 2; m = 2, n = 0) depending on the identity of R and R′. The crystal structures of [Ti₂(µ-NBu^t)₂(OC₆ H₃Me₂-2,6)₄] 1 and [Ti(NC₆H₃Me₂-2,6)(OC₆H ₃Me₂-2,6)₂(py)₂] have been determined. Extended-Hückel molecular orbital calculations for models of 1 showed that the deviation of the µ-imido Bu^t substituents from coplanarity with the Ti₂N₂ core in this and some related species can be attributed to a second-order Jahn–Teller distortion.

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