Hydrolysis and Complexation of N,N-Dimethylformamide in New Nanostructurated Titanium Oxide Hybrid Organic-Inorganic Sols and Gel

International audienceWe recently synthesized new hybrid organic-inorganic sols and gel obtained by the slow hydrolysis of N,N-dimethylformamide (DMF) by TiOCl2 acidic solution. The comprehension of the synthesis mechanism of these materials, made up of Ti-O framework surrounded by organic molecules, is important to understand their original photochemical properties. The use of Raman spectroscopy provides information on the role of DMF for the complexation of Ti4+ and its subsequent hydrolysis in dimethylammonium chloride (DMACl) and methanoate species during the nanostructuration. The study of the reaction by spectroscopies gives key information on the sols-gel formation. Part of DMF is bound to Ti4+ since the beginning of the reaction inducing an oriented growth of the inorganic network. Furthermore, the selective hydrolysis of DMF linked to titanium allows the formation of methanoate species located in the Ti4+ coordination sphere. These surface-attached molecules appear to be of great importance to form the structure of these materials. Moreover, they are involved in the original photoelectrochemical properties of these sols and gel, which can usefully be employed for solar energy conversion and storage