Theoretical study on structure and electronic properties of 4h-cyclopenta [2,1-b,3;4-b’]dithiopene s-oxide and its Ccl2 and Cf2 bridged derivatives

Abstract EN

Quantum chemical calculations using semi-empirical, ab initio, density functional theory (DFT) and Møller plesset (MP2) methods were performed on 4H-Cyclopenta[2,1-b,3;4-b’]dithiopene S-oxide derivatives (i.e.

bridged dithiophene S-oxides, BTOs).

The geometries, stabilities, electronic and thermodynamic properties of the compounds were studied.

The thermodynamic parameters calculated at PM3 were in good agreement with those calculated at B3LYP/6-31G(d) level.

The band gap energies calculated at B3LYP/6-31G(d) level for the BTOs were lower than the un-substituted trithiophene but higher than 4H-Cyclopenta[2,1-b,3;4-b’]dithiopene (Bouzzine, 2005).

The absorption λmax calculated using TD-DFT was shifted to longer wavelength by successive replacement of methylene hydrogens of BTO by chlorine and fluorine atoms.-