Synthesis, optical and redox properties of novel segmented cyano-PPV derivatives

We report the detailed synthesis and physical characterization of two novel segmented PPV derivatives 6 and 7, that contain cyano-modified DSB-segment s covalently linked with different ether groups. The polymers were synthesi zed by step growth polymerization via the KNOEVENAGEL reaction. They exhibi t high molecular weights (Mn similar to 20,000 VPO) and can be cast from so lution to give transparent, orange films with high PL quantum efficiencies (40 %). In comparison to the cyano-free polymers the electrochemical reduct ion potential is remarkably low (E-Red -1.30 V vs. Ag/AgCl in solid state), indicating a high electron affinity. Thus, the new polymers offer promise as electron transporting materials for photoconductive or light-emitting de vices and as novel materials for X-(3) NLO applications.