Synthesis, structure, and urease inhibitory activities of three binuclear copper(II) complexes with protocatechuic acid derivative

Abstract

Three Cu(II) complexes, [Cu^II₂(L₁)₄(L₂)₂] (1), [Cu^II₂(L₁)₄(H₂O)₂]·HL (2), and [Cu^II₂(L₁)₃(L₃)₂]ClO₄ (3), with a ligand derived from protocatechuic acid (HL₁ = C₉H₈O₄=2,3-dihydrobenzo[b][1,4]dioxine-6-carboxylic acid, L₂ = C₇H₉N=o-toluidine, L₃ = C₆H₁₆N₂=N,N-diethylethylenediamine) were synthesized and characterized by C, H, and N elemental analysis and single-crystal X-ray diffraction, which revealed that the three complexes have similar binuclear structures. Complexes 1 and 3 crystallized in triclinic space group P-1 and 2 in orthorhombic space group P2₁2₁2₁. The urease inhibitory activities of the three complexes were tested. All three complexes showed strong inhibitory activity against jack bean urease with an IC₅₀ value of 6.8, 5.5, and 3.5 μM compared with the acetohydroxamic acid (IC₅₀ = 7.5 μM), which was a positive control.

Graphical Abstract

Keywords:

• Copper(II) complex
• Crystal structure
• Urease inhibitors
• Protocatechuic acid

Funding

We thank the financial support from National Natural Science Foundation of China [grant number 31200090]; Scientific Research Foundation for Returned Scholars, Ministry of Education of China and China Postdoctoral Science Foundation National [grant number 1302006A].