Polymerization of 3-Methyl-2,5-Dibromothiophene Utilizing n-Butyl Lithium and Copper(II) Chloride.

In recent years, there have been extensive research activities focussed on macromolecules with extended pi-electron system. Among the many macromolecules studied, conjugated olefinic compounds polyenes, have been given much attention. Various methods for their synthesis have been reported. In the heterocyclic category, there are four reports on the synthesis of poly3-substituted-2,5-thienylene substituent H, CH3 via coupling of 3-substituted-2,5-dibromothienylmagnesium by nickel salt promoters. Recently Afanasev, et al. reported also about the preparation of poly2,5-thienylene by an electrochemical method. The ability for charge transport through the thiophene polymer chain is an important criterion for achieving high conductivity. For that reason the synthesis of polyenes was studied. The present investigation was undertaken to improve the synthesis of poly3-methyl-2,5-thienylene and to obtain a magnesium free material. n-Butyl lithium was used as dehaloginating agent. CuII chloride was utilized to serve as catalyst.