Synthesis, crystal structures, and antimicrobial activity of copper(II) complexes derived from N′ -(1-(pyridin-2-yl)ethylidene)isonicotinohydrazide

Two mononuclear copper(II) compounds, [Cu(HL)2](ClO4)2 · (H2L)ClO4 · 3H2O (1) and [CuL2] (2), where L is the monoanionic form of N′-(1-(pyridin-2-yl)ethylidene)isonicotinohydrazide (HL), have been prepared and characterized by elemental analyses, IR, and single crystal X-ray crystallographic determination. Compound 1 contains a [Cu(HL)2]2+ complex cation, a H2L+ cation, three perchlorate anions, and three water molecules of crystallization. Compound 2 contains one neutral [CuL2] complex molecule. The Cu atoms in the complexes are in octahedral coordination, with the hydrazone ligands coordinate to the Cu atoms through the pyridine N, imine N, and enolate O atoms. The effect of the compounds on the antimicrobial activity against Staphylococcus aureus, Escherichia coli, and Candida albicans was studied.