Improved DNA equilibrium binding affinity determinations of platinum(ii) complexes using synchrotron radiation circular dichroism

Abstract

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 (47Me₂phen), 5,6-dimethyl-1,10-phenanthroline (56Me₂phen) or 3,4,7,8-tetramethyl-1,10-phenanthroline (3478Me₄phen) 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.