Uranyl-Bridged Polyoxometalate Assembled from Te-Oriented Three-Layered Cage Clusters for Photocatalytic Oxy-Thiocyanation of Alkenes.

A novel uranyl-containing tellurotungstate dimer, [(CH3)2NH]4Na2H14{(Te3W21O75)2[UO2(H2O)]2}·37H2O (U2TeW), was successfully synthesized with two prolonged lacunary Dawson-type units and systematically characterized. The dimeric architecture consists of two [Te3W21O75]12- clusters, each presenting a rare three-layered configuration with three symmetry-equivalent TeO3 heteroatoms, which intersect at an angle of 45.317° to form a well-defined cavity that encapsulates two [UO2(H2O)]2+ units serving as bridging linkers. Notably, U2TeW exhibits efficient photocatalytic activity for the oxy-thiocyanation of terminal alkenes using molecular oxygen as a green oxidant, producing valuable α-thiocyanato ketones in high yields (up to 87%) under mild conditions. The catalyst shows excellent stability and reusability over six cycles. This work not only broadens the family of actinide-incorporated polyoxometalates but also provides insights into their potential applications in organic synthesis.