The present study focuses on the design and synthesis of a cage-like organic skeleton containing two triazole rings jointed via imine linkage. These molecules can act as urease inhibitors. The in-vitro urease inhibition screening results showed that the combination of the two triazole skeleton in the cage-like morphology exhibited comparable urease inhibition activity to that of the reference thiourea while the metallic complexation, especially with copper, nickel, and palladium, showed excellent activity results with IC₅₀ values of 0.94 ± 0.13, 3.71 ± 0.61, and 7.64 ± 1.21 (3a–c), and 1.20 ± 0.52, 3.93 ± 0.45, and 12.87 ± 2.11 µM (4a–c). However, the rest of compounds among the targeted series exhibited a low to moderate enzyme inhibition potential. To better understand the compounds’ underlying mechanisms of the inhibitory effect (3a and 4a) and their most active metal complexes (3b and 4b), we performed an enzymatic kinetic analysis using the Lineweaver–Burk plot in the presence of different concentrations of inhibitors to represent the non-competitive inhibition nature of the compounds, 3a, 4a, and 4b, while mixed type inhibition was represented by the compound, 3b. Moreover, molecular docking confirmed the binding interactive behavior of 3a within the active site of the target protein.

Designing and developing small organic molecules for use as urease inhibitors is challenging due to the need for ecosystem sustainability and the requirement to prevent health risks related to the human stomach and urinary tract. Moreover, imaging analysis is widely utilized for tracking infections in intracellular and in vivo systems, which requires drug molecules with emissive potential, specifically in the low-energy region. This study comprises the synthesis of a Schiff base ligand and its selected transition metals to evaluate their UV/fluorescence properties, inhibitory activity against urease, and molecular docking. Screening of the symmetrical cage-like ligand and its metal complexes with various eco-friendly transition metals revealed significant urease inhibition potential. The IC₅₀ value of the ligand for urease inhibition was 21.80 ± 1.88 µM, comparable to that of thiourea. Notably, upon coordination with transition metals, the ligand–nickel and ligand–copper complexes exhibited even greater potency than the reference compound, with IC₅₀ values of 11.8 ± 1.14 and 9.31 ± 1.31 µM, respectively. The ligand–cobalt complex exhibited an enzyme inhibitory potential comparable with thiourea, while the zinc and iron complexes demonstrated the least activity, which might be due to weaker interactions with the investigated protein. Meanwhile, all the metal complexes demonstrated a pronounced optical response, which could be utilized for fluorescence-guided targeted drug delivery applications in the future. Molecular docking analysis and IC₅₀ values from in vitro urease inhibition screening showed a trend of increasing activity from compounds 7d to 7c to 7b. Enzyme kinetics studies using the Lineweaver–Burk plot indicated mixed-type inhibition against 7c and non-competitive inhibition against 7d.