Syntheses, X-ray structures and CVD of titanium(iv) arsine complexes

Abstract

Five titanium arsine compounds have been synthesised via the reaction of TiCl₄ with AsPh₃ (1 : 1 and 1 : 2 equivalents), or one equivalent of Ph₂AsCH₂AsPh₂, ^tBuAsH₂ and As(NMe₂)₃. In general, 1 : 1 and 1 : 2 adducts of the type [TiCl₄(L)_n] (n = 1, L = AsPh₃, Ph₂AsCH₂AsPh₂, and ^tBuAsH₂; n = 2, L = AsPh₃), were isolated and characterised. However, the reaction of TiCl₄ with As(NMe₂)₃ resulted in a novel exchange between a Cl and an NMe₂ group, yielding the product [TiCl₃(NMe₂)(μ-NMe₂)₂AsCl]. The crystal structure of [TiCl₃(NMe₂)(μ-NMe₂)₂AsCl] has been determined and showed that the titanium and arsenic atoms are linked via two bridging NMe₂ groups. Additionally, crystal structures for the 1 : 1 and 1 : 2 adducts, [TiCl₄(AsPh₃)] and [TiCl₄(AsPh₃)₂] have been obtained, with Ti–As bond lengths of 2.7465(13) and 2.7238(7) Å observed respectively. The decomposition of the compounds has been investigated using thermogravimetric analysis, aerosol-assisted and low pressure chemical vapour deposition.