Group 2 titanium heterometallic alkoxides;: their reproducible syntheses and characterization.: Crystal structures of the compounds [SrTi4(OEt)18] and [Sr2Ti(OPri)8(PriOH)3]•2PriOH

The reactions of either (i) bulk metal in alcohol (EtOH or (PrOH)-O-i); or (ii) the preformed metal alkoxides, [M(OR)(2)(ROH)(x)](n), with a stoichiometric amount of Ti(OPri)(4) at reflux yielded the novel hydrocarbon soluble molecular aggregates [MTi2(OEt)(10)(EtOH)(5)](n) [M = Sr (1) and Ba (2)]; [MTi4(OEt)(18)] [M = Sr (3) and Ba (4)]; [M2Ti(OEt)(8)(EtoH)(5)](n), [M = Sr (5) and Ba (6)]; and [Sr2Ti (OPri)(8)((PrOH)-O-i)(3)].2Pr(i)OH (7). All complexes have been characterized by elemental analyses and spectroscopic methods; (3) and (7) have also been characterized by X-ray crystallography. The structure of (3) is based on a "bow-tie" Ti2SrTi2 unit where the strontium is coordinated to two face sharing bioctahedral Ti-2(OEt)(9)(-) units, via two "terminal" and two "bridging" ethoxo ligands from each Ti-2(OEt)(9)(-) unit. In (7) the Sr2Ti unit forms a triangle, bridged by three mu(2)-(PrO)-O-i ligands and capped by two mu(3)-(PrO)-O-i ligands, and further supported by six terminal (PrO)-O-i/(PrOH)-O-i ligands. (C) 1998 Published by Elsevier Science Ltd. All rights reserved.