Structural and Electronic Properties of Oligomeric Heteroarylene Vinylenes: A Theoretical Approach

Abstract

The structural and electronic properties of trans-bis (2-thienyl)ethylene, trans-bis(2-furyl)ethylene and trans-bis(2-pyrryl) ethylene have been investigated from a theoretical standpoint. Ab initio methods have been employed to calculate the geometric structures and ionization potentials. Furthermore, VEH ionization potentials and π-π* electronic transitions are reported. A progressive decrease of the ionization potential occurs when exchanging sulfur by oxygen and when replacing oxygen by a NH group. An increase of the energy of the first electronic transition is observed in going from trans-bis(2-thienyl)ethylene to trans-bis(2-furyl)ethylene but not when passing to trans-bis(2-pyrryl)ethylene. These trends are correlated with available theoretical and experimental data on polymers. The adequacy of ab initio and VEH methods to predict correctly the electronic properties of trans-bis(2-furyl)ethylene is discussed.