ESR spectroscopy of the elimination of sulfinyl precursor polymers towards PPV

We investigated the elimination of the sulfinyl precursor polymer towards poly(p-phenylene vinylene), PPV, by means of ESR spectroscopy. In this technique the radicals formed during and after elimination can be detected. A comparison with the Wessling, route i.e. sulfonium groups eliminating towards PPV, a larger signal during and a smaller signal after elimination was recorded when elimination was performed under nitrogen flow. These observations indicate that during elimination radicals are formed which can be assigned to the elimination products which undergo sequential reactions after formation of the sulfenic acid upon elimination. The smaller signal after elimination which is in general subscribed to defects or endgroups, indicates a more pure PPV with less defects obtained from the sulfinyl precursor route in comparison with PPV obtained from the sulfonium precursor route.