Synthesis and characterisation of functionalised thiophene copolymers with electron donor and acceptor substituents

The synthesis of new donor/acceptor 3-substituted thiophene copolymers with two different alkyl substituents is presented. The new alternating (3-alkyl/3-cyano)thiophene copolymers were prepared via the Stille coupling reaction involving 2,5-bis-tri(n-butyl)tin-3-cyanothiophene and 2,5-dibromo-3-alkylthiophenes in the presence of catalytic amounts of palladium tetrakistriphenylphosphine. The new materials were characterised by NMR and UV-Vis spectroscopy and their molecular weights determined by gel permeation chromatography. The physical properties of the different copolymers are discussed in relation with their different alkyl group substituents (R = n-decyl and cyclohexyl).