Maximizing the solar energy storage of di-substituted norbornadiene—quadricyclane system through electronic effects

The aim of this research is a determination of solar energy storage in norbornadiene (1)—quadricyclane (2) sytem by two direct attachments of substituents at both carbon atoms of double bond C2=C3 in 1 and 2 at the B3 LYP/6–311++G** level of theory. Two electron donating substituents, (pull-pull effect), X (X = -NH2, -OMe, Me, -F, -Cl, and -Br), directly attached at both carbon atoms of double bond C2=C3, increase the splitting of energy between 1 X and 2 X, inducing higher storage of solar energy in the system. Two electron withdrawing subsituents, (push-push effect) X (X = -NO2 and CF3), decrease the solar energy storage. Highest solar energy storage was devoted to pull-push substituents 1NH₂ - NO₂ .