The influence of loops on the binding of the [Ru(phen)2dppz]2+ Light-Switch Compound to i motif DNA Structures revealed by Time-resolved Spectroscopy

Ultrafast time resolved infrared (TRIR) is used to report on the binding site of the [Ru(phen)2(dppz)]2+ 1 “light-switch” complex to i-motif structures in solution. Detailed information is provided due to perturbation of the local base vibrations by a ‘Stark-like’ effect which is used to establish the contribution of thymine base loop interactions to the binding site of 1 in this increasingly relevant DNA structure.