Structural Analysis of Selenium Coordination Compounds and Mesoporous TiO(2)-Based Photocatalysts for Hydrogen Generation.

This study reports the synthesis of ten coordination compounds (1-10) derived from the ligand bis((3-aminopyridin-2-yl)selanyl)methane (L) and different metal centers (Co(II), Cu(I), Cu(II), Zn(II), and Ag(I)). Single crystals of the complexes were obtained via slow diffusion from overlaid solutions of ligand L and the corresponding metal. Their crystalline structures were determined by single-crystal X-ray diffraction (SCXRD) and further characterized using spectroscopic, spectrometric, and voltammetric techniques. Complexes 1-5, 7, and 10 were evaluated as cocatalysts of mesoporous titanium dioxide (m-TiO(2)) for photocatalytic hydrogen production via water photolysis under solar light simulation, using triethanolamine (TEOA) as the sacrificial agent. The results showed that complexes 4, 5, 7, and 10 enhanced m-TiO(2) photocatalytic activity, achieving hydrogen evolution rates at least four times higher than standard m-TiO(2) and P25. Among these, the photocatalyst m-TiO(2)-7 (7 = [Cu(2)(μ-SO(4))(2)L(2)]) exhibited the highest hydrogen production, reaching approximately 7800 μmol/g over a 6-h experiment-nearly 26 times greater than pure m-TiO(2) (300 μmol/g). These findings highlight the potential of organoselenium metal complexes for the development of novel photocatalytic materials based on nonprecious metals.