Bismesitoylphosphinic Acid (BAPO-OH): A Ligand for Copper Complexes and Four-Electron Photoreductant for the Preparation of Copper Nanomaterials

Bismesitoylphosphinic acid, (HO)PO(COMes)(2)(BAPO-OH), is an efficient photoinitiator for free-radical polymerizations of olefins in aqueous phase. Described here are the structures of various copper(II) and copper(I) complexes with BAPO-OH as the figura The complex Cu-II-(BAPO-O)(2)(H2O)(2) is photoactive, and under irradiation with UV light in aqueous phase, it serves as a source of metallic copper in high purity and yield (> 80%). Simultaneously, the radical polymerization of acrylates can be initiated and allows the preparation of nanoparticle/polymer nanocomposites in which the metallic Cu nanoparticles are protected against oxidation. The determination of the stoichiometry of the photoreductions suggests an almost quantitative conversion from Cu-II into Cu-0 with half an equivalent of BAPO-OH, which serves as a four-electron photoreductant.