Lead-Decorated Titanium Oxide Compound with a High Performance in Catalytic CO 2 Insertion to Epoxides.

The CO cycloaddition to epoxides is an efficient method for CO capture and storage, important not only for reducing greenhouse gas emission but also for producing cyclic carbonates, which are valuable industrial materials. In this study, we report a novel high-nuclearity titanium oxide cluster (TOC) inlayed with main-group element Pb, HTiPbO(SA)(DMF)(OH) (denoted as ; SA = salicylate; DMF = ,-dimethylformamide), which has the property of visible-light absorption and has shown high catalytic activities for cycloadditions of CO under visible-light irradiation. The cluster was synthesized in a high yield in a facial solvothermal process. Its structure and electronic structure were characterized by single-crystal X-ray diffraction, density functional theory calculations, and complementary techniques. The cycloaddition reactions were performed under solvent-free conditions. While the catalytic activity due to the Lewis acidity was moderate, visible-light irradiation further folded the reaction rates. The turnover number reached 3400 with a turnover frequency of 120 h. Mechanism studies indicated a synergistic effect of the Lewis acidity and photogenerated charge carriers. The performance of in reversible I uptake was also investigated. This study demonstrates the high potential of heterometal-decorated TOCs in the cost-effective and efficient CO cycloaddition reaction under mild conditions.