Self-activated DNA cleavage and nitric oxide reactivity studies on mononuclear copper complexes derived from tetradentate ligands

Two new tetradentate ligands Timpy (1,2-bis((E)-(2-phenyl-2-(pyridine-2-yl)hydrozono)methyl)benzene) and Gimpy ((1Z,2Z)-1,2-bis(2-phenyl-2-(pyridine-2-yl)hydrozono)ethane) were synthesized and characterized. Mononuclear complexes [Cu(Timpy)(ClO4)](ClO4) (1) and [Cu(Gimpy)](ClO4)2 (2) were synthesized and characterized by IR, UV–visible and conductivity measurements. The molecular structure of [Cu(Timpy)(ClO4)](ClO4) (1) was determined by single crystal X-ray diffraction and structural index parameter (τ = 0.4725) supported distorted square planar geometry at the metal centre. Electrochemical studies for 1 and 2 were investigated. Two-fold applications of these complexes were examined. First, self-activated DNA cleavage activity of complexes 1 and 2 and mechanism of nuclease activity. Second, the complexes were utilized as fluorescence probe for the detection of nitric oxide in solution.