Control of conjugation in poly(arylenevinylene)s

Poly(1,4-phenylenevinylene) (PPV) and derivatives have been studied extensively for use in polymer based LEDs. It has been shown that the introduction of low levels of saturated units into the polymer backbone can give LEDs with improved efficiency. We have developed a new route to partially conjugated PPV derivatives enabling the final polymer to be formed with ethylene links bearing no leaving groups. This was achieved by the treatment of the chloro precursor to poly{2-(2'-ethyl)hexyloxy-5-methoxy-1,4-phenylenevinylene} (MEHPPV) with different amounts of tri-n-butyltin hydride to form copolymers which contain selected proportions of unsubstituted and chlorine substituted ethylene linkages. The subsequent thermal conversion gave rise to conjugated copolymers containing ethylene and vinylene linkages.