Synthesis, DNA-binding, and Photocleavage of 2,3-Di-2-pyridylquinoxaline-silver(I) Complex

A new dinuclear complex, [Ag(L)(CH3CN)]2(ClO4)2 2H2O(L=2,3-di-2-pyridylquinoxaline), was prepared and characterized by elemental analyses, IR spectroscopy, and single-crystal X-ray diffraction analyses. The interaction of the complex with calf thymus DNA(CT-DNA) was investigated by absorption, fluorescence spectroscopies, and viscosity measurement. The results suggested that the complex was bound to DNA via an intercalative mode. The intrinsic binding constant value Kb was found to be approximately 1.48×103 L·mol−1. Moreover, the Ag(I) complex could cleave the plasmid pUC19 DNA from the supercoiled Form I to the nicked Form II under irradiation at 365 nm.