The nonlinear optical properties and noncovalent interactions of supramolecular Donor-acceptor-donor assemblies between molecular tweezers and fullerenes

The supramolecular donor-acceptor-donor (D-A-D) system were formed between the tweezer and C-60 with strong intermolecular charge transfer interactions, which enhance the two-photon absorption (TPA) cross-section. Here, we would use density functional theory method to investigate three effects of molecular structures on the intermolecular interactions and the second order NLO properties of supramolecular complexes, including: (1) the effects of N atom substitution in tweezer (2) the effects of four extra benzene rings in tweezer (3) the effect of fullerene size. It was found that the substitution of N atoms and the addition of the four extra benzene rings to tweezer weakened the intermolecule interactions between fullerene and tweezer, suggesting that they did not enhance the electron-giving capacities of tweezers. While the fullerenes of larger size can form the stronger intermolecule interaction with tweezers.