A Tris(triphenylphosphine)ruthenium(II) Complex as a UV Photoinitiator for Free-Radical Polymerization and in Situ Silver Nanoparticle Formation in Cationic Films

Abstract

The characterization and the photochemical investigation of a RuII complex (Ru(PPh3)3Cl2) having phosphine ligands are reported. DFT calculations and ESR spin trapping experiments revealed for the first time that the photodecomposition of the complex is governed by a homolytic cleavage of the P–(C6H5) bond generating phenyl radicals Ph• which are able to initiate the free radical polymerization of acrylate monomers. The addition of a H-donor HD plays a key role in the cationic photopolymerization of epoxides: (i) the reaction efficiency is enhanced using [Ru(PPh3)3Cl2]/HD and (ii) the in situ formation of Ag nanoparticles is observed in the presence of Ru(PPh3)3Cl2/HD/AgSbF6 according to the following reactions: Ph•/DH hydrogen abstraction yielding a D• radical and oxidation of D• by the silver salt.