N'-(2-Hydroxy-4-methoxybenzylidene)-4-methylbenzohydrazide and its dinuclear nickel(II) and cadmium(II) complexes: Synthesis, crystal structures and urease inhibition.

Hydrazone compounds and their nickel(II) and cadmium(II) complexes have interesting biological activities. To explore new and efficient urease inhibitors, in this work an aroylhydrazone compound N'-(2-Hydroxy-4-methoxybenzylidene)-4-methylbenzohydrazide (HL) and two complexes [Ni2L2(CH3OH)2(OH2)2]Cl2·2CH3OH (1) and [Cd2L2(CH3COO)2] (2) have been prepared and characterized by elemental analysis, infrared and electronic spectroscopy, as well as single crystal X-ray determination. In addition, 1H and 13C NMR spectroscopy was used for HL. Both complexes are dinuclear compounds. The Ni atoms in complex 1 are in octahedral coordination, and the Cd atoms in complex 2 are in square pyramidal coordination. The Cl- in 1 acts as a counter anion, while the NO3- in 2 coordinates to the metal atoms with bidentate form. The urease inhibitory assay reveals that HL has weak activity, while complexes 1 and 2 have IC50 values of 18.2 ± 1.1 μmol L-1 and 0.38 ± 0.12 μmol L-1, respectively. Both complexes have higher activity than the standard drug acetohydroxamic acid (IC50 = 28.1 μmol L-1).