Synthesis, structural characterization and DNA-binding studies of a new cobalt (II) complex: (HAcr)4[Co(Sal)3

Abstract

A new cobalt (II) coordination compound was synthesized using proton transfer mechanism. The reaction between CoCl2·2H2O, Salicylic acid (H2Sal) and acridine (Acr) gave a new coordination compound formulated as (HAcr)4[Co(Sal)3], which was characterized by elemental analysis, NMR, IR and UV/Vis spectroscopies. The interaction of this complex with DNA has been investigated in vitro using UV absorption, fluorescence spectroscopy, viscosity measurements and gel electrophoresis methods. The intrinsic binding constant has been estimated to be 5.8 × 105 M−1 using UV absorption. The interaction of DNA–Co (II) complex caused quenching in fluorescence. The binding constant, the number of binding site and Stern–Volmer quenching constant have been calculated to be 7.7 × 104 M−1, 1.143 and 1.5 × 104 Lmol−1, respectively. The increase in the viscosity of DNA with increasing the concentration of the Co (II) complex and the observations of other experiments suggest that the cobalt (II) complex binds to DNA by partial intercalation binding mode. Furthermore, the interaction of DNA–Co (II) complex was confirmed using gel electrophoresis studies. Moreover, molecular docking technique predicted partial intercalation binding mode for the complex.