Influence of bridging atoms in copper-based coordination polymers for enhancing urease inhibition activity

Urease may rapidly hydrolyze urea, causing a significant amount of ammonia to be released and decreasing the efficacy of urea fertilizers. However, urease inhibitors (UIs) can prevent the interaction between urease and urea, allowing crops to absorb ammonium nitrogen for an extended period of time. In this paper, by using different O-donor second auxiliary ligands, we have designed and synthesized two Cu-based coordination polymers (Cu-CPs) to operate as UIs by combining two aromatic carboxylic acids and a bis-pyridine-bis-amide ligand, which show excellent urease inhibitory activity. Cu-CP-1 has an obvious inhibitory effect on the inhibitory activity against jack bean urease, with the IC50 of 1 being 0.83 +/- 0.01 mu M while the IC50 value for Cu-CP-2 was 2.53 +/- 0.01 mu M, respectively. Furthermore, inhibitory activity against urease, kinetics, molecular docking, and comparisons of the title Cu-CPs and other complex-based materials have been comprehensively investigated. More importantly, the bridging atoms of mu 2-OH and mu 2-Cl play important roles in urease inhibition activity. The structure-function relationships were further discussed and indicate that Cu-CPs can be used as a kind of UI. By using different O-donor second auxiliary ligands, we have designed and synthesized two Cu-based CPs with different bridging atoms to operate as urease inhibitors which show excellent urease inhibitory activity.