Improved DNA equilibrium binding affinity determinations of platinum(ii) complexes using synchrotron radiation circular dichroismElectronic supplementary information (ESI) available. See DOI: 10.1039/c5an00066a

The binding affinity of a series of square planar platinum( ii ) compounds of the type [Pt(A L )(I L )] 2+ , where A L is 1,2-diaminoethane and I L are 1,10-phenanthroline (phen), 4-methyl-1,10-phenanthroline (4Mephen), 5-methyl-1,10-phenanthroline (5Mephen), 4,7-dimethyl-1,10-phenanthroline (47Me 2 phen), 5,6-dimethyl-1,10-phenanthroline (56Me 2 phen) or 3,4,7,8-tetramethyl-1,10-phenanthroline (3478Me 4 phen) has been reinvestigated using Synchrotron Radiation Circular Dichroism (SRCD) spectroscopy. The additional peaks exhibited considerably greater intensity than those observed between 200 and 400 nm affording additional binding affinity determinations. In addition, the authors have reviewed the various mathematical approaches used to estimate equilibrium binding constants and thereby demonstrate that their mathematical approach, implemented with Wolfram Mathematica , has merit over other methods. The DNA binding affinity of a range of Pt( ii ) complexes was reinvestigated using SRCD and a new method was implemented for determining the binding constant, saving time and minimising data collection.