Structural studies of polythiophenes

Kilic, GB
Toppare, Levent Kamil
Yurtsever, E
A theoretical investigation of the electronic structures of the oligomers of thiophene (T) and their derivatives, namely, 2-methylthiophene (2MT), 3-methylthiophene (3MT), 2-cyanothiophene (2CT) and 3-cyanothiophene (3CT), are presented. The most stable forms of the monomer, dimer, trimer and tetramers are obtained by the semi-empirical quantum mechanical methodology using AM1 parametrization. All possible binding sites are investigated in order to understand the bonding in polythiophenes. The 3-substituted molecules form dimers which lie nearly at trans-planar positions but 2CT and 2MT favor cis conformations. The activation energies between these structures and local minima change from 0.2 to 1.8 kcal/mol. Methyl- and cyano-substituted polythiophenes favor linear growth mechanisms. The branching requires 3-6 kcal/mol per substitution. Polythiophenes seem to form fairly flexible chains as understood from the relatively low rotational barriers.

Citation Formats
G. Kilic, L. K. Toppare, and E. Yurtsever, “Structural studies of polythiophenes,” SYNTHETIC METALS, vol. 78, no. 1, pp. 19–25, 1996, Accessed: 00, 2020. [Online]. Available: