Titanium(IV) complexes of oximes - Novel binding modes

摘要

In this paper we investigate the coordination of various oximes (C=N-OH) with titanium(IV). We have chosen three ligands (1H(2)-3H(2)) with a phenolic moiety and one ligand 4H with a pyridine group. It was shown that ligands 1H(2) to 3H(2) react with Ti((OPr)-Pr-i)(4) to form complexes with a generic formula Ti-3(L)(2)((OPr)-Pr-i)(8), where each oxime bridges between the three titanium centres. Interestingly, these complexes are clusters made up of three titanium atoms, with one titanium centre sitting above the other two. This titanium centre can be thought of as a trapped Ti((OPr)-Pr-i)(4) molecule, H-1 and C-13 NMR spectroscopy indicates that the solid-state structures are maintained in solution. Subtle differences between the three X-ray structures are discussed. Ligand 4H readily reacts with Ti((OPr)-Pr-i)(4) forming a dimeric species, Ti-2(4)(4)((OPr)-Pr-i)(4), where the titanium centres are linked by bridging isopropoxide moieties. (c) 2006 Elsevier Ltd. All rights reserved.