Dual-linker Ir–Zr-MOF shows improved porosity to enhance aqueous sulfide photooxidation

The hetero photooxidation of sulfide under aqueous conditions is of great importance in the green synthesis of sulfoxide. This process requires a type of solid photocatalyst with the properties of high porosity and water stability, as well as photosensitivity. Herein, a stable Ir–Zr-MOF material (compound 1) with high porosity is assembled from two linear linkers of a 2-phenylquinoline-4-carboxylic acid-Ir(III) complex (Irphen) and 4,4′-stilbenedicarboxylic acid (H2SDC), and a Zr6 cluster. 1 is isostructural to JLU-Liu34 with a composition of [Zr6O4.78(OH)3.22(SDC)3.82(Irphen)0.78TFA2.8]·2.8MeOH and permanent porosity with a BET surface area of 1507 m2 g−1. 1 exhibits improved activity for the photocatalytic aerobic oxidation of sulfide to sulfoxide via blue light irradiation under aqueous conditions. Mechanism studies demonstrate that a superoxide radical is the reactive oxygen species in the sulfide photooxidation. 1 can be readily recycled and reused at least 5 times without loss of catalytic activity. This work not only provides a good strategy for the assembly of an Ir(III) complex into MOFs but also an efficient method for the green synthesis of sulfoxide.