Synthesis and crystal structures of two new titanium alkoxy–diolate complexes. Potential precursors for oxide ceramics

Abstract

The new titanium alkoxy–diolate precursors [Ti(OCH2CH2O)(OCH2CH2NMe2)2]2 (1) and [Ti(OCMe2CMe2O)(OCH2CH2NMe2)2]2 (2) have been prepared and structurally characterised by single crystal X-ray diffraction. Both compounds exhibit binuclear centrosymmetric structures with bridging alkoxide groups, containing two six-coordinate Ti atoms in distorted octahedral environments. In (1) the oxygen from the ethylene glycolate ligand is involved in bridging, whereas in (2) the bridging oxygen is provided by the dimethylamino ethoxide ligand. Complexes (1) and (2) are potential precursors for Ti-containing oxides and both complexes have been investigated as precursors for the deposition of TiO2 thin films by liquid injection metalorganic chemical vapour deposition (MOCVD). Significantly, only complex (2) led to reproducible TiO2 deposition in the temperature range 325–450 °C, whilst complex (1) exhibited a marked pre-reaction leading to highly irreproducible film growth. The difference in MOCVD behaviour between the complexes is rationalised in terms of their molecular structure.