Synthesis, Characterization and Crystal Structures of Copper(II) Complexes Derived from 4-Hydroxy-N’-(2-hydroxy-5-methyl-benzylidene)-3-Methoxybenzohydrazide and 4-Hydroxy-N’-(2-hydroxy-3-methoxybenzylidene)Benzohydrazide with Antibacterial Activity

Aroylhydrazones with various substituent groups and their metal complexes have interesting biological activities. In this work, two new copper(II) complexes Cu2(La)22NO3∙2MeOH (1) and CuLb(CH3OH)2NO3∙CH3OH (2), derived from the aroylhydrazones 4-hydroxy-N’-(2-hydroxy-5-methylbenzylidene)-3-methoxybenzohydrazide (HLa) and 4-hydroxy-N’-(2-hydroxy-3-methoxybenzylidene) benzohydrazide (HLb), were synthesized and characterized by physico-chemical methods such as elemental analysis and infrared spectroscopy. Structures of the complexes were confirmed by single crystal X-ray determination. The hydrazone ligands in the complexes coordinate to Cu ions through phenolate oxygen, imino nitrogen and carbonyl oxygen atoms. The Cu ions in complex 1 are in square planar coordination, and that in complex 2 is in square pyramidal coordination. Both complexes show good antibacterial activities on the bacterial strains Bacillus subtilis, Staphylococcus aureus and Escherichia coli, while weak activity on the fungal strain Candida albicans and no activity on Aspergillus niger.