Synthesis of Light-Emitting Polymers via Heck coupling reactions

Conjugated polymers represent a very promising class of organic materials for photonics and electronics, which exhibits a unique combination of optical and electrical properties typical of semiconductors with processing advantages and mechanical features of polymers. Light-emitting devices (LED) were first fabricated from small organic molecule, having the main disadvantage that they can re-crystallize during device operation, leading to poor device stability. The use of conjugated polymers, potentially more stable, in such devices was first realized in the early 1990. The most efficient polymeric systems are actually based on poly(p-phenylenevinylene) (PPV) films, which emit basically green 1ight. However, there is still a big challenge in obtaining highly efficient blue-light-emitting devices. Among the several methods reported for the synthesis of PPV, the Heck coupling between an organic halide and an olefin, giving a carbon-carbon double bond, shows to have a great potential. In the present paper we reported on the palladium catalyzed synthesis of PPV starting from p-di-iodobenzene and an olefin.