Zn-triazole coordination polymers: Bioinspired carbonic anhydrase mimics for hydration and sequestration of CO2

Abstract

Artificial enzyme mimics have recently emerged as alternative biocatalysts for overcoming the intrinsic fragility of natural enzyme in practical applications. However, current researches regarding mimetic enzymes are still confined to very few reaction types, with artificial oxidoreductases as dominance. Herein, inspired by nature, we designed and fabricated a range of Zn-Triazole coordination polymers (ZnTazs) that presented similar coordination structures with the active site of natural carbonic anhydrase Ⅱ (CA Ⅱ). These synthesized compounds exhibited inherently mimetic function with natural CA for catalyzing the hydrolysis of p-nitrophenyl acetate (p-NPA). Especially, the initial hydrolysis rate (V0) of p-NPA catalyzed by ZnTaz-1 (Zn5(bta)6(NO3)4 · H2O) and ZnTaz-2 (Zn3(OH)2(btca)2 · DMF · 4 H2O) reached 42.1 and 73.8 nM · s−1, respectively. Meanwhile, ZnTaz-1 and ZnTaz-2 showed favorable recyclability, and excellent stability towards various pH values and organic solvents, which are of great significance for practical employment. Moreover, they could also promote the efficient hydration and sequestration of greenhouse gas CO2 in aqueous medium. Based on this work, we aim to provide more theoretical and practical basis for rational design of CA mimics from the inspiration of natural enzyme, as well as propose a potential strategy for tackling the CO2 crisis.