Amino-Polyalcohol-Solvothermal Synthesis of Titanium-Oxo Clusters: From Ti to Ti with Structural Diversity.

As is known, amino-polyalcohol ligands are usually used as sacrificial agents in photocatalytic reactions. And polyoxo-titanium clusters (PTCs) are molecular modes of titanium dioxide, one of the most important photocatalysts. In order to help understand the intrinsic coordination feature of amino-polyalcohol toward titanium-oxo species, we carried out the research of constructing PTCs with amino-polyalcohol ligands. In view of the low melting point of amino-polyalcohol, they have been directly applied as reaction mediums. Under this new synthetic method, a series of PTCs have been successfully obtained, namely, Ti(μ-O)(OCHCHO)(O Pr)(dea)·HO Pr (deaH = diethanolamine, PTC-171), Ti(μ-O)(μ-O)(tea)(O Pr)(dea)(teaH = triethanolamine, PTC-172), Ti(μ-O)(μ-O)(O Pr)(dea) (PTC-173), Ti(μ-O)(μ-O)(dea)Cl (PTC-174), and Ti(μ-O)(μ-O)(dea)(NO)·(HO) (PTC-175). Their structures are determined by single-crystal X-ray diffraction analysis. It is worth noting that PTC-174 and PTC-175 are not only the first Ti examples of crystalline PTCs, but also currently the largest PTCs compounds in the amino-polyalcohol system. Moreover, the solid-state UV-vis spectra of these PTCs were recorded. And their applications in photocurrent responses were also investigated. This work provides an interesting method for the preparation of amino-polyalcohol base PTCs and would also benefit the mechanism interpretation of the photocatalytic processes of titanium oxide materials.