Synthesis of di-, tri- and penta-nuclear titanium(IV) species from reactions of titanium(IV) alkoxides with 2,2′-biphenol (H2L1) and 1,1′-binaphthol (H2L2);: crystal structures of [Ti3(μ2-OPri)2(OPri)8L1], [Ti3(OPri)6L13], [Ti5(μ3-O)2(μ2-OR)2(OR)6L14] (R = OPri, OBun) and [Ti2(OPri)4L22]

Reaction of titanium(IV) alkoxides [Ti(OR)(4)] (R = OPri, OBun) with 2,2'-biphenol [C12H8(OH)(2), H2L1] affords two trinuclear species [Ti-3(OPri)(10)L-1] and [Ti-3(OPri)(6)L-3(1)] each possessing an open- chain V-shaped arrangement of three titanium atoms with the former having both bridging alkoxide and biphenylate groups and the latter having only biphenylate as bridging groups. Variations in reaction conditions yield the pentanuclear species [Ti-5(mu(3)-O)(2)(OR)(8)L-4(1)] (R = OPri, OBun) which have two central bridging oxygen atoms in the Ti5 framework and bridging alkoxide and biphenylate groups. In contrast 1,1'-binaphthol [C24H12(OH)(12), H2L2] yields the dinuclear [Ti-2(OPri)(4)L-2(2)] where only the binaphthylate ligands act as bridging groups. Some of the compounds show catalytic activity in esterification reactions.