Enhancing Third-Order Nonlinear Optical Property by Regulating Interaction between Zr(embonate) Cage and N, N-Chelated Transition-Metal Cation.

Herein, the combination of anionic ZrL (L = embonate) cages and N, N-chelated transition-metal cations leads to a series of new cage-based architectures, including ion pair structures ( and ), dimer (), and 3D frameworks ( and ). Structural analyses show that exhibits a 2-fold interpenetrating framework with a 3,4-connected topology, and shows a 2-fold interpenetrating framework with a 4-connected network. Both and can be stable in air and other common solvents at room temperature. The investigations of third-order nonlinear optical (NLO) properties indicate that these materials show different degrees of optical limiting effects. It is surprising that increasing coordination interactions between anion and cation moieties can effectively enhance their third-order NLO properties, which can be attributed to the formation of coordination bonds that facilitate charge transfer. In addition, the phase purity, UV-vis spectra, and photocurrent properties of these materials were also studied. This work provides new ideas for the construction of third-order NLO materials.