Ionic Cu18-methylsilsesquioxane/dppm complex: synthesis, structure, and catalytic activity

Interaction of copper methylsilsesquioxane and dppm (1,1-bis(diphenylphosphino)methane) causes an intriguing redistribution of copper ions between O- and P,P-ligands. This “ligands competition” provides an unprecedented ionic complex 1 with dianionic Si16CuII12-methylsilsesquioxane cage and two external CuI3(dppm)3Cl2-cations. Cage component exhibits an unusual ability to encapsulate two species of different nature (chloride and hydroxyl). Complex 1 catalyses the one-pot peroxidative oxidation of cyclohexane to ε-caprolactone using m-chloroperoxybenzoic acid (mCPBA) as the oxidant, without the need for an acid promoter and under mild conditions. © 2025 Elsevier B.V.