Synthesis, Crystal Structures, and Photochemical Properties of a Family of Heterometallic Titanium Oxo Clusters.

The incorporation of heterometallic atoms into the structure of titanium-oxygen nanomaterials is one of the known and effective strategies to develop new high-performance photovoltaic active materials. In this study, we have synthesized three benzoic acid-stabilized heterometallic titanium oxo clusters with the different transition metals Co, Cu, and Cd, formulated as [TiCo(μ-O)(μ-O)(CHCOO)(CHCN)]·2CHCN (1), [TiCu(μ-O)(CHCOO)] (2), and [TiCd(μ-O)(μ-O)(μ-O)(CHCOO)(CHCOOH)(CHCN)]·CHCN·CHCOOH (3), and then we characterized their structures. UV-vis spectroscopy analysis revealed an enhanced UV-vis-light absorption of those heterometallic clusters. The density functional theory calculations indicated that charge transfer occurs from the p orbital of O atoms to the d orbital of Ti atoms in the TiO core (O → Ti) as well as from the metal to the core in 1 and 2. We also measured the photocurrent response and photocatalytic H evolution, which shows enhancement in the photocurrent intensity and good H evolution ability because of the cooperative effect of heterometal doping in titanium oxo clusters.