Photoluminescence of Titanosilsesquioxanes in Solution and Its Relevance for the Understanding of the Emission of Titanosilicates

A model for the titanium sites in solid titanosilicates is provided by titanosilsequioxanes in solution. Five model compounds, such as the one shown in the picture, have a variety of titanium coordination styles, were investigated. Emission maxima and lifetimes, quantum yields, and the effects of solvent and gas provide information on the nature of the titanium binding in the models and shown to be indicative of catalytically active titanium sites in the titanosilicates.