CuNiO2 nano catalyst for efficient Csp2–S bond formation in water: toward green synthesis of bioactive molecules

Abstract

A green and efficient method for Migita-type Csp²–S cross-coupling of aryl halides with thiols has been developed using a heterogeneous CuNiO₂ bimetallic nanocatalyst. This low-cost, easily synthesized catalyst operates under ligand-free conditions in water, enabling the coupling of heterocyclic thiols such as benzothiazole-2-thiol, benzooxa-zole-2-thiol, 1,3,4-thiadiazole-2-thiol, and thiazole-2-thiol with challenging electrophiles like 3-bromopyridine, 2-bromoquinoline, and 5-bromo-1H-indole. The methodology demonstrates broad scope and practicality, including gram-scale synthesis of diverse aryl, heteroaryl, and alkyl thioethers bearing bioactive motifs. Compared to existing systems, this catalyst exhibits greater sustainability and catalytic performance. Control experiments confirm a synergistic effect between Cu and Ni, while DFT calculations indicate that the reaction preferentially occurs at the Ni center, with an overall Gibbs free energy change of −102.7 kcal mol⁻¹.