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

The new titanium alkoxy-diolate precursors [Ti(OCH2CH2O)(OCH2CH2NMe2)(2)](2 ) (1) and [Ti(OCMe2CMe2O)(OCH2CH2NMe2)(2)](2) (2) have been prepared and st ructurally characterised by single crystal X-ray diffraction. Both compound s exhibit binuclear centrosymmetric structures with bridging alkoxide group s, containing two six-coordinate Ti atoms in distorted octahedral environme nts. In (1) the oxygen from the ethylene glycolate ligand is involved in br idging, whereas in (2) the bridging oxygen is provided by the dimethylamino ethoxide ligand. Complexes (1) and (2) are potential precursors for Ti-con taining 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 reproduc ible TiO2 deposition in the temperature range 325-450 degreesC, whilst comp lex (1) exhibited a marked pre-reaction leading to highly irreproducible fi lm growth. The difference in MOCVD behaviour between the complexes is ratio nalised in terms of their molecular structure.