DNA-binding and cleavage studies of novel copper(II) complex with l-phenylalaninate and 1,4,8,9-tetra-aza-triphenylene ligands

DNA-binding properties of novel copper(II) complex [Cu(l-Phe)(TATP)(H2O)]+, where l-Phe = l-phenylalaninate and TATP = 1,4,8,9-tetra-aza-triphenylene are investigated using electronic absorption spectroscopy, fluorescence spectroscopy, voltammetry and viscosity measurement. It is found that the presence of calf thymus DNA results in a hypochromism and red shift in the electronic absorption, a quenching effect on fluorescence nature of ethidium bromide–DNA system, an enhanced response on voltammograms of [Co(phen)3]3+/2+–DNA system, and an obvious change in viscosity of DNA. From absorption titration, fluorescence analysis and voltammetric measurement, the binding constant of the complex with DNA is calculated. The latter two methods reveal the stronger binding of [Cu(l-Phe)(TATP)(H2O)]+ complex to double strand DNA by the moderate intercalation than [Co(phen)3]3+. Such a binding induces the cleavage of plasmid pBR322 DNA in the presence of H2O2.