Porous 3d-4f Coordination Clusters for Selective Visible-Light Photocatalytic CO2 Reduction to CO.

We report herein two families of porous coordination clusters (PCCs) with 216 nuclearity (M120RE96 or PCC-216MR) and 300 nuclearity (Co144Gd156 or PCC-300CG). For the first family M could be either nickel or cobalt, and RE = Pr, Nd, Sm, Eu, and Gd; while the latter features the highest nuclearity of transition-rare earth metal clusters. Characterized by their cube-like, hollow structures, these clusters exhibit the ability to absorb N2 and CO2. Besides, these clusters can be dissolved in both aqueous and acetonitrile/methanol solutions, and capable of acting as homogeneous catalysts for converting CO2 to CO under visible light. The gadolinium analogues of these clusters all show turnover numbers over 10000 and turnover frequencies over 1 s-1. In particular, the nickel based bimetallic cluster (PCC-216NG) demonstrates near ly 100% selectivity for the reduction product, which may open a new direction for the design and development of PCCs based catalysts.