Synthesis, structural and spectral properties of Au complexes: luminescence properties and their non-covalent DNA binding studies

Gold complexes of 1,3- bis-pyridylimidazolium chloride (L1), 1,3-bis-[2,6-diisopropylphenyl]imidazolium chloride (L2) and 1,3-bis-[benzyl]benzimidazolium chloride (L3) were synthesized and characterized by analytical methods. For the complexes, electronic spectral results show that there is a marked difference in the band feature observed in the spectra, ascribed to the greater relativistic effect of gold. In fluorescence studies, the complexes develop emission bands in the visible region (400-600nm) after excitation at around 350nm. Au complex-DNA binding was studied, and it was observed that genomic DNA isolated from the U373-GB cell line was fragmented and in some cases degraded by the Au complexes. Furthermore, the intensity of the DNA band increased when concentration of the metal complex was augmented. This study shows that the DNA cleavage is mediated by the Au complex. Copyright (c) 2013 John Wiley & Sons, Ltd.