Push–pull effect on the electronic, optical and charge transport properties of the benzo[2,3-b]thiophene derivatives as efficient multifunctional materials

In the present study new derivatives have been designed by bridge elongation and push–pull strategy from 4,6-di(thiophen-2-yl)pyrimidine with the aim to enhance electronic and charge transport properties. Density Functional Theory and Time Dependent Density Functional Theory have been applied to optimize the ground and excited state geometries, respectively. The absorption and emission wavelengths have been computed at TDB3LYP/6-31G**, TDLC-BLYP/6-31G**, TDM05/6-31G** and TDM052X/6-31G** level of theories, then discussed and compared with available experimental data. The vertical and adiabatic ionization potentials (IPa/v), vertical and adiabatic electron affinities (EAa/v), hole and electron reorganization energies (λ (h)/(e)) have been calculated. The effect of bridge, electron activating groups and electron deactivating groups has been studied. The B3LYP functional is better to reproduce the experimental data than the LC-BLYP, M05 and M052X. The substituent effect has also been investigated on the IP, EA, λ (h) and λ (e) by plotting these values as a function of Hammett constants. The structure–property relationship has been discussed intensively.