Syntheses, Crystal Structures and DNA-Binding Properties of Cu(II)/Ni(II) Complexes with Acylhydrazone Ligand Bearing Pyrazine Unit

Two complexes, namely [Ni(L)(HL)](SO4)(05)center dot 3CH(3)OH (1) and [Cu-2(L)(2)SO4]center dot 1.5CH(3)OH (2) (HL=3-methyl-2-acetylpyrazine benzoylhydrazone) have been synthesized and characterized by single crystal X-ray diffraction, elemental analysis and IR spectroscopy. X-ray diffraction analysis results showed that in complex 1, the center Ni (II) ion with a distorted octahedron geometry is surrounded by two acylhydrazones with [ONN] donor set. However, complex 2 contains one discrete dimeric Cu(II) molecule in the unit cell, in which two Cu(II) ions were doubly bridged by two O atoms from two independent acylhydrazone ligands. Each of the Cu(II) ions is also coordinated by two N atoms from one ligand and one O atom from the eta(2)-SO42- anion, thus giving a distorted square pyramid coordination geometry. Moreover, the fluorescence spectra indicated that the interaction of the complexes to DNA is stronger than that of the ligand HL. CCDC 1876785: 1; 1876789: 2.