Stimuli-responsive Zn(ii) complexes showing the structural conversion and on/off switching of catalytic properties†

Abstract

In this work, we report a series of dinuclear Zn(II) complexes and their corresponding catalytic properties for a transesterification reaction. We show that the structures and catalytic activity of the complexes are strongly dependent on their molecular structures surrounding the metal centres. The use of halides yields a series of [Zn₂X₄L] (X = Cl, Br, and I) complexes with low catalytic activity because of the fully saturated coordination environment, whereas Zn(ClO₄)₂ results in two isomeric [ZnL]_n 1D coordination polymers with efficient catalytic properties, despite being susceptible to structural rearrangement and consequent changes in catalytic activity over time. The response to chemical stimuli to trigger anion exchange allows for switching on/off the systems' catalytic activity, simultaneously recovering the catalytic effect upon degradation and thus reconstructing the coordination environment of the 1D polymer.