Copper cluster complex-catalyzed C–S bond formation†

Three distinct copper cluster complexes (A–C) containing Cu–O ligated Schiff-base ligands were synthesized and their bonding was investigated by single-crystal X-ray crystallographic studies. These complexes effectively catalyze the C–S cross coupling reaction of less reactive aliphatic thiols to synthesize thioether derivatives. This coupling reaction also tolerates well and is compatible with aryl thiols. The peculiar C(sp²)–SC(sp³) bond formation distinctly took place with high efficiency using low loading of copper cluster complex catalysts. The present report describes an alternative protocol to construct active copper cluster complexes from readily accessible, cheap and efficient ligands. These complexes are air stable, practical, easy to handle and catalyze C–S coupling reactions with good yields.