Synthesis, structure and DNA binding studies of 9-phenyldibenzo[a,c] phenazin-9-ium†
Abstract
The reaction of phenanthrene-9,10-dione with N-phenylbenzene-1,2-diamine in methanol in the presence of anhydrous CuCl2 and HCl affords a 9-phenyldibenzo[a,c]phenazin-9-ium cation, [1]+, as in [1][CuCl2], in good yields. The reaction of [1][CuCl2] in methanol with excess iodide salt affords [1][I]. The formations of [1][CuCl2] and [1][I] have been confirmed by elemental analyses, mass, IR, UV-vis and 1H NMR spectra including the single crystal X-ray structure determination of [1][CuCl2]. DNA binding studies by UV-vis spectra, fluorescence spectra, circular dichroism spectra, hydrodynamic, isothermal titration calorimetric (ITC), UV optical melting and gel electrophoresis experiments have substantiated that [1]+, like ethidium bromide, is a strong DNA intercalator.