A tetranuclear diphenyltin(IV) complex and its catalytic activity in the aerobic Baeyer-Villiger oxidation of cyclohexanone

The synthesis and crystal structure of the new tetranuclear diphenyltin(IV) compound [{SnPh2}{SnPh2(OCOMe)}(μ2-OMe)(μ3-O)]2 (1), generated from the reaction of [SnPh2Cl2] and NaOCOMe, are described. Single crystal X-ray diffraction revealed that 1 is a tetranuclear complex with four diphenyltin(IV) units which are inter-connected by μ3-oxido and μ2-methoxido bridges leading to a ladder-like Sn4O4 cluster. Structural comparison with related compounds found in crystallographic data base (CSD) attests that such tetranuclear systems are more abundant than related oxido bridged dimers or trimers. Complex 1 efficiently catalyzes the aerobic Baeyer-Villiger oxidation of cyclohexanone to ε-caprolactone, under mild conditions. With the sacrificial benzaldehyde method, quantitative conversion was observed in just 30 min with a remarkable selectivity. © 2018 Elsevier B.V.