Dinuclear cobalt and nickel complexes of a mercaptoacetic acid substituted 1,2,4-triazole ligand: syntheses, structures and urease inhibitory studies.

Because of its versatile coordination modes and strong coordination ability, the mercaptoacetic acid substituted 1,2,4-triazole 2-{[5-(pyridin-2-yl)-4H-1,2,4-triazol-3-yl]sulfanyl}acetic acid (HL) was synthesized and characterized. Treatment of HL with cobalt and nickel acetate afforded the dinuclear complexes {μ-3-[(carboxylatomethyl)sulfanyl]-5-(pyridin-2-yl)-4H-1,2,4-triazol-4-ido-κN,N:N,O}bis[aqua(methanol-κO)cobalt(II)] methanol disolvate, [Co(CHNOS)(CHOH)(HO)]·2CHOH (1), and {μ-3-[(carboxylatomethyl)sulfanyl]-5-(pyridin-2-yl)-4H-1,2,4-triazol-4-ido-κN,N:N,O}bis[diaquanickel(II)] methanol disolvate dihydrate, [Ni(CHNOS)(HO)]·2CHOH·2HO (2), respectively. Complex 1 crystallized in the monoclinic space group P2/c, while 2 crystallized in the tetragonal space group I4/a. Single-crystal X-ray diffraction studies revealed that HL is doubly deprotonated and acts as a tetradentate bridging ligand in complexes 1 and 2. For both of the obtained complexes, extensive hydrogen-bond interactions contribute to the formation of their three-dimensional supermolecular structures. Hirshfeld surface analysis was used to illustrate the intermolecular interactions. Additionally, the urease inhibitory activities of 1, 2 and HL were investigated against jack bean urease, where the two complexes revealed strong urease inhibition activities.