Improving the optical properties of [5] circulene with different electron donors and acceptor substitutions (push-pull system)

In this research, the circulene molecule was selected, and the electron donor and acceptor groups were attached to improve its optical properties. Large negative values of enthalpies, Gibbs free energies, and exothermic energies of formation for these molecules, especially for the CN-CIR-NHLi molecule, show that their formation is highly reasonable. It was illustrated that the E-g of the circulene molecule was lowered in the electron donor and acceptor groups' presence, while the CN-CIR-NHLi and CF3-CIR-NHLi molecules have the lowest values of E-g. It was observed that the optical properties of circulene molecules were improved in electron donor and acceptor groups' presence. Between these groups, the -CN and -CF3 as electron acceptors and -NHLi substituents, as electron donor groups, yield higher enhancements on the optical properties of circulene, which is in agreement with the results obtained for E-g values.