Zinc(II) and copper(II) complexes with N-substituted imines derived from 4-amino-1,2,4-triazole: Synthesis, crystal structure, and biological activity

Abstract

Reactions of copper(II) and zinc(II) acetates with polynitrogen Schiff bases, namely 4-(pyridin-2-yl)methyleneamino-1,2,4-triazole (L1), 4-(pyridin-3-yl)methyleneamino-1,2,4-triazole (L2) and 4-(pyridin-4-yl)methyleneamino-1,2,4-triazole (L3), were studied. The reaction of Zn(OAc)2·2H2O and L1 gave crystals of trinuclear complex [Zn3(OAc)6(L1)2] (1). A similar reaction of Zn(OAc)2·2H2O and L2 resulted in 1D coordination polymer [Zn(OAc)2(L2)]n (2). The reactions of Cu(OAc)2·H2O with L2 or L3 gave crystals of 1D coordination polymer {[Cu2(OAc)4(L2)]·2MeCN}n (3) and binuclear complex [Cu2(OAc)2(L3)2]·2MeCN (4), respectively. The structures of the coordination compounds thus obtained were determined by single-crystal X-ray diffraction analysis. Complexes 1–4 demonstrated better antibacterial and antifungal activities in comparison with free L1, L2, and L3 ligands: the strongest antimicrobial activity was observed against E. coli for 2 and 3, and the highest antifungal activity was found for 1 and 2.