Synthesis and crystal structures of cobalt(III), copper(II), nickel(II) and zinc(II) complexes derived from 4-methoxy-N′-(pyridin-2-ylmethylene)benzohydrazide with urease inhibitory activity

Urease catalyzes the decomposition of urea into ammonia, which has harmful effects on both human health and fertile soil. Aiming at exploring novel urease inhibitors, a series of hydrazone compounds and their Co-III, Cu-II, Ni-II, and Zn-II complexes were prepared from 4-methoxy-N'-(pyridin-2-ylmethylene)benzohydrazide (HL). They are [CoClL(NCS)] (1), [CoL2]center dot Cl center dot CH3OH center dot H2O (2), [CuL(NCNCN)](n)center dot nCH(3)OH (3), [NiL(HL)]center dot ClO4 center dot CH3OH (4) and [ZnClL(OH2)]center dot CH3OH (5). The compounds were characterized by physico-chemical methods. Structures of the complexes were further confirmed by single crystal X-ray diffraction. The metal ions in 1, 3, and 5 display square pyramidal coordination and 2 and 4 display octahedral coordination. The inhibitory effects of the compounds on Jack bean urease were evaluated. The results showed that 3 has effective urease inhibitory activity, with IC50 value of (7.3 +/- 1.0) mu mol L-1.