Reactivity of AlMe3 with titanium(IV) Schiff base complexes:: X-ray structure of [Ti{(μ-Br)(AlMe2)}{(μ-Br)(AlMe2X)}(salen)]•C7H8 (X = Me or Br) and reactivity studies of mono-alkylated [Ti(Me)X(L)] complexes

[TiCl2(salen)] (1) reacts with AlMe3 (1:2) to give the heterometallic Ti(III) and Ti(IV) complexes [Ti{(mu-Cl)(AlMe2)}{(mu-Cl)(AlMe2X)}(salen)] (X = Me or Cl) (2) and [TiMe{(mu-Cl)(AlCl2Me)}(salen)] (3). Addition of diethyl ether to 3 affords [Ti(Me)Cl(salen)] (4). The analogous reaction of [TiBr2(salen)] (5) gives the crystallographically characterised [Ti{(mu-Br)(AlMe2)}{(mu-Br)(AlMe2X)}(salen)] (X = Me or Br) (6) and [Ti(Me)Br(salen)] (7) in a single step, whilst the comparable reaction of [TiCl2{(3-MeO)(2)salen}] (8) with AlMe3 yields [Ti(Me)Cl{(3-MeO)(2)salen}] (9) with no evidence of titanium(III) species. Reactivity of both halide and methyl groups of 4 has been probed using magnesium reduction, SbCl5 and AgBF4 halide abstraction and SO2 insertion reactions. Hydrolysis of [Ti(Me)X(L)] complexes affords mu-oxo species [TiX(L)](2)(mu-O) [X = Cl, L = salen (13); X = Br, L = salen (14); X = Cl, L = (3-MeO)(2)salen (15)]. (C) 1999 Elsevier Science S.A. All rights reserved.