Asymmetry-Induced Redistribution in Sn(IV)–Ti(IV) Hetero-Bimetallic Alkoxide Precursors and Its Impact on Thin-Film Deposition by Metal–Organic Chemical Vapor Deposition

International audience; With an aim to enhance the stability and volatility of the heterometallic derivative [SnCl4(µ-OEt)2Ti(OEt)2(HOEt)2] (A), obtained conveniently and quantitatively as a simple adduct formula from the equivalent reaction of commercially available SnCl4 and Ti(OEt)4 in toluene/ethanol, its modification with 2,2,6,6-heptane-3,5-dione (thdH) is reported. The modified precursor [SnCl4(µ-OEt)2Ti(thd)(OEt)(HOEt)] (1), obtained from equimolar reaction of A and thdH, is stable at room temperature but rearranges on heating into A and [SnCl4(µ-OEt)2Ti(thd)2] (2), as confirmed by the vapor pressure measurements and DFT calculations. The heterometallic 2 can be obtained in excellent yield from the reaction of A and thdH in 1:2 molar ratio and is stable in solid and solution phase up to 200 °C. However, the asymmetric nature of its structure consisting of fragments of titanium β-diketonate and tin chloride connected by bridging ethoxo groups, leads to breakdown into two homometallic components in gas phase, leading to deposition of tin-rich metal oxide films on the substrate.