Theoretical study on the photophysical properties of chiral mononuclear and dinuclear zinc complexes

The chiroptical, linear, and second-order nonlinear optical (NLO) properties of chiral mononuclear and dinuclear zinc complexes have been investigated for the first time at density functional theory level. The calculated electron absorption energies and oscillator strengths are in reasonable agreement with the experimental ones. The good agreement between the experimental and the simulated CD spectra shows that TDDFT calculations can be used to assign the absolute configurations (ACs) of chiral zinc complexes with high confidence. Based on these calculated results, the electron transition property and chiroptical origin have been analyzed and assigned. The results show that the coordinated Zn atoms have certain effects on the chiroptical property. The larger nonlinear optical response mainly results from interligand and intraligand charge transfer. The studied complexes have a possibility to be excellent second-order nonlinear optical material from the standpoint of first hyperpolarizability value, transparency and intrinsic non-centrosymmetric electronic structure.