Theoretical predictions for occurrence of charge transfer complex within the two synthesized bichromophores considering the role of their spacers in interactions with the π-orbitals of the redox centers

Computational work has been done for the bichromophores comprising a donor molecule 4 methoxy-benzo[b]thiophene (4MBT) and an acceptor molecule p-chloro-acetophenone (PCA) linked together by unsaturated and saturated olefinic spacers, HCCH and H2CCH2. The difference between the ground and excited singlet state dipole moments confirmed the electron transfer probability. The possibility of formation of ground state charge transfer complex in case of the bichromophoric systems is indicated by time dependent density functional theory (TD-DFT) with B3LYP/6-311G(d,p) theoretical and semi-empirical RHF-SCF-PM3 calculation and confirmed experimentally by electronic absorption (UV–Vis) spectroscopic measurements.