A simple synthetic route for neutral and ionic non-conjugated phosphorescent iridium-containing copolymers

Series of neutral and ionic non-conjugated metal-containing copolymers are readily prepared via the free-radical copolymerization of benzyl methacrylate (BzMA) with two phosphorescent Ir(III) complexes, [Ir(ppy)2(AIm)Cl](1) and [Ir(ppy)2(AIm)2]PF6 (2PF6), respectively. The copolymers are soluble in polar organic solvents, easily forming a film on glass, aluminum foil or plastic materials. The neutral copolymers have weight-average molecular weights (Mw) of ca. 30,000–60,000 g/mol. Although the thermal stabilities of the neutral and ionic copolymers both increase with increasing amount of Ir(III) complex, the ionic copolymers are more thermally stable than their neutral analogs. With a suitable amount of Ir(III)-complex content, the neutral non-conjugated copolymerization between the Ir complex and BzMA can induce a blue shift in the max value of copolymer relative to that observed for complex 1. For the neutral and ionic copolymers, the observed max value in the film are red-shifted to those observed in solution.

► One and two allyl groups in phosphorescent complexes allow the copolymerization of the complexes with benzyl methacrylate (BzMA).
► The copolymers are soluble in many organic solvents, forming a film with good thermal stability.
► The neutral non-conjugated copolymerization between the Ir complex and BzMA can induce a blue shift in the λmax value of the copolymer.