Fluorescence and photochromic properties of a series of new Zn(ii)/Cd(ii) coordination compounds with a flexible semi-rigid tetrazole–viologen derivative

Abstract

Photoluminescent coordination compounds have appealing applications in light-emitting and photoactive materials, but there exist some difficulties in the tuning and domination of luminescence by changing the structures. In this work, diverse luminescence was realized by the rational design and controllable construction of a series of Zn(II)/Cd(II) coordination compounds from an isolated binuclear moiety, a 1D zigzag chain, a 1D ladder-like chain and a 3D 3,4-connected topology network based on a flexible semi-rigid tetrazole–viologen ligand. Especially, the isolated binuclear compound shows an interesting photochromic molecular system that involves electron transfer from the N₃⁻ ions and Cl atoms to the tetrazole–viologen ligand and exhibits fluorescence and second-order nonlinear optical property variation upon ultraviolet light irradiation.