LAUSR

Abstract A Cu(II) complex based on a pyrazolone derivative, 2-hydroxy-N′-((1-(4-methoxyphenyl)-3methyl-5-oxo-4,5-dihydro-1H-pyrazol-4-yl)(phenyl)methylene)benzohydrazide (H2L), has been prepared. IR spectra, UV-vis spectra, elemental analysis and single-crystal X-ray diffraction indicate that the Cu(II) complex was mononuclear with the chemical composition of [Cu(HL)Cl]·CH3OH. The Cu(II) compound presented herein exhibits interesting supramolecular characteristics and a novel 3D supramolecular architecture resulted due to the appropriate synergy of multiple intermolecular hydrogen bonds. The interaction of the Cu(II) complex with calf-thymus DNA was investigated by electronic absorption titration as well as EB-DNA competition experiment, and the results indicate that the Cu(II) compound which has a strong affinity for binding DNA is combined with DNA in an embedded manner. Furthermore, Time-Dependent Density Functional Theory calculations (TD-DFT) have been performed on optimized geometries for a better understanding of the electronic transitions in the UV-vis spectra of H2L and Cu(II) complex.