Synthesis, magnetic, and optoelectronic properties of poly(triphenylamine-alt-phenylenevinylene)s

Conjugated polymers alternatively involving m-phenylenevinylene or p-phenyl enevinylene and a triphenylamine moiety in the main chain were synthesized via a Wittig-Horner-type polycondensation of 4-diformyl-4',4 " -dimethyl-tr iphenylamine or 4-diformyl-4',4 " -dimethoxy-triphenylamine with m-xylene-b is(diethylphosphonate) or p-xylene-bis(diethylphosphonate). A high glass-tr ansition temperature (ca. 120 degreesC) and thermal stability (5% weight lo ss at temperatures greater than 450 degreesC) were observed for all polymer s. These polymers, especially poly(methyltriphenylamine-alt-p-phenyleneviny lene), fluoresced a strong green color under UV irradiation, with a quantum efficiency of 50% for their chloroform solutions. Cyclic voltammetry showe d a relatively low ionization potential (5.18-5.44 eV) for the polymers. Th ese results suggest that these polymers satisfied the requisites of polymer materials for a single-layer light-emitting diode. The aminium radical der ived from the oxidation of poly(triphenylamine-alt-m-phenylenevinylene) sat isfied both non-Kekule-type pi conjugation and ferromagnetic connectivity o f the unpaired electrons and displayed a multiplet ground state. (C) 2000 J ohn Wiley & Sons, Inc.