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 [Cu 2 (L a ) 2 ]2NO 3 ∙2MeOH ( 1 ) and [CuL b (CH 3 OH) 2 ]NO 3 ∙CH 3 OH ( 2 ), derived from the aroylhydrazones 4-hydroxy- N’ -(2-hydroxy-5-methylbenzylidene)-3-methoxybenzohydrazide (HL a ) and 4-hydroxy- N’ -(2-hydroxy-3-methoxybenzylidene) benzohydrazide (HL b ), 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 .