SYNTHESIS AND CHARACTERIZATION OF TELECHELIC REGIOREGULAR HEAD-TO-TAIL POLY(3-ALKYLTHIOPHENES)

An investigation into the Stille cross-coupling reaction as an alterna tive synthetic route to regioregular head-to-tail poly(3-alkylthiophen es) is presented. 2-Iodo-3-alkyl-5-tri-n-butylstannylthiophene derivat ives were made, isolated and characterised and subsequently used in Pd -0 catalysed cross-coupling reactions in different solvents. Short and long chain regioregular poly(3-hexylthiophenes) with over 96% head-to -tail coupling ratios between adjacent thiophene rings were obtained. The materials were analysed by gel permeation chromatography and NMR s pectroscopy. Polymers with varying degrees of polymerisation were obta ined depending on the conditions used. End group analysis has shown th at polymers, functionalised with both iodo and tri-n-butyltin end grou ps can be obtained under certain reaction conditions. Preliminary homo coupling reactions were also conducted.