Elucidating the Mechanism of Polymerization using Synchrotron X-Ray Absorption Spectroscopy

Polymerization of 3-hexylthiophene (3HT) with FeCb is simple, efficient, and has been widely adopted for both laboratory and industrial scale production purpose. However, there remains considerable debate regarding the polymerization mechanism. We have used partial fluorescence yield X-ray absorption fine structure (XAFS) techniques to monitor the change in valence state of the solid FeCb particles in CHCh and hexane. The FeCb acts as a catalyst when the reaction is performed in CHCb. but behaves as an oxidant in hexane. The catalytic behavior is attributed to the decomposition of CHCfo. which has been previously reported to oxidize Fe2+ to Fe3+. This is the first report on the catalytic role of FeCb during the polymerization of 3HT in CHCI3.