Oxidative Coupling of Poly (2-Vinylthiophene) Chains by FeCl3

Summary Poly(2-vinylthiophene) (PVT) can be cross linked with FeCl₃ either in dichloromethane solution or when immobilized on silica particles. Extend of cross linking is strongly dependent on the FeCI₃/PVT ratio used for the reaction as shown by GPC plots and gravimetric analyses of the formed insoluble polymer fraction. A stoichiometric FeCl₃/PVT ratio of about four is necessary to achieve complete conversion, because consecutive formations of thiophene H⁺FeCl₄ ^- and bisthiophene H⁺FeCl₄ ^- sigma complexes take place. PVT can be also cross linked when adsorbed on silica using the same procedure. The cross-linking is proved by IR and ¹³C CPiMAS NMR spectroscopy.