Tuning the Architectures of Copper Coordination Frameworks through Nitrogen-Containing Auxiliary Ligands and Evaluating Their Urease Inhibition Behavior

Abstract

This study systematically investigates the role of nitrogen-containing auxiliary ligands in modulating the structures of copper coordination frameworks and their effects on urease inhibitory activity. A series of copper coordination frameworks were successfully synthesized using different types of nitrogen-containing ligands. The frameworks were comprehensively characterized by X-ray diffraction, infrared spectroscopy, UV–visible spectroscopy, thermogravimetric analysis, and elemental analysis to determine their crystal structures, metal center coordination environments, pore sizes, and thermal stabilities. Experimental results indicate that the electronic effects and steric hindrance of the auxiliary ligands significantly influence the formation and stability of the frameworks, thereby affecting their overall topology and pore characteristics. In urease inhibition assays, frameworks with different structures exhibited distinct inhibitory effects, which were closely related to framework stability, metal center geometry, and pore features. Structure–activity relationship analysis further revealed that stable frameworks with favorable electronic environments enhance interactions with urease, resulting in higher inhibitory efficiency. This study not only elucidates the regulatory mechanisms of auxiliary ligands on the structure and bioactivity of copper coordination frameworks but also provides theoretical guidance for the design of novel metal-based urease inhibitors and lays a foundation for the further development of coordination frameworks in biological applications.