Design and Evaluation of Copper-Based Coordination Polymers for Enhanced Urease Inhibition in Agricultural Systems

Abstract

Efficient nitrogen utilization remains a critical challenge in modern agriculture due to rapid urea hydrolysis catalyzed by urease, which results in nitrogen loss and environmental pollution. The development of stable and environmentally friendly urease inhibitors is therefore essential. In this study, a series of copper-based coordination polymers (Cu-CPs) were designed and synthesized to evaluate their potential as novel urease inhibitors. The Cu-CPs were characterized using X-ray diffraction (XRD), Fourier-transform infrared spectroscopy (FTIR), and UV–Vis spectroscopy, confirming the formation of stable three-dimensional coordination networks. In vitro assays demonstrated that the Cu-CPs effectively inhibited urease activity in a dose-dependent manner, with some compounds exhibiting non-competitive inhibition and lower IC50 values compared to conventional small-molecule inhibitors. Soil incubation experiments further revealed that Cu-CPs significantly delayed urea hydrolysis, resulting in more gradual nitrogen release and improved nitrogen use efficiency. Importantly, their application showed minimal disturbance to soil microbial communities, suggesting potential safety for agricultural use. Mechanistic analysis indicated that the inhibitory effect arises from the coordination of copper ions with the urease active site, while the polymeric network allows controlled release, maintaining sustained enzyme inhibition. Compared to traditional urease inhibitors, Cu-CPs provide enhanced stability, prolonged activity, and reduced environmental risk, making them promising candidates for practical agricultural applications. This study highlights the potential of metal-based coordination polymers as efficient, stable, and environmentally compatible urease inhibitors, offering a new strategy to optimize nitrogen fertilizer utilization and mitigate environmental nitrogen loss in agricultural systems.