Mononuclear copper(II) complexes with a tetradentate pyrazole based ligand: Syntheses, structures, DNA binding study and antimicrobial activity

摘要

A new tetradentate N_4-coordinate ligand, N,N-diethyl-N', N'-bis((3,5-dimethyl-1H-pyrazol-1-yl)methyl)ethane-1,2-diamine (dbdmp), and its mononuclear copper(II) complexes [Cu(X)(dbdmp)]Y, where X = N _3, NCS, NCO and Y = ClO_4, PF_6 and BF _4, have been synthesized and characterized by microanalysis, physico-chemical and spectroscopic methods. The crystal structures of the four complexes [Cu(N_3)(dbdmp)]ClO_4 (1) [Cu(NCS)(dbdmp)]ClO _4 (4), [Cu(NCS)(dbdmp)]PF_6 (5) and [Cu(NCO)(dbdmp)] ClO_4 (7) were solved by single crystal X-ray diffraction studies and showed that all the complexes have distorted trigonal bipyramidal geometries. Interaction of CT-DNA with complexes 1-6 were examined by spectroscopic titration and fluorescence techniques and showed that the complexes have strong interactions with CT-DNA. The antimicrobial activities of complexes 1-6 were studied by the dilution method against Gram positive (Bacillus subtilis) and Gram negative (Escherichia coli) strains and showed the complete inhibition of the tested strains by the complexes.