Explaining the Role of Water in the “Light-Switch” Probe for DNA Intercalation; Modelling Water Loss from [Ru(phen)2(dppz)]2+•2H2O using DFT and TD-DFT Methods

作者：Aoibhín A. Cullen^*; Conor Long^*; Mary T. Pryce^*

来源：Journal of Photochemistry and Photobiology A: Chemistry , 2021, 113169.

DOI：10.1016/j.jphotochem.2021.113169

• Ruthenium
• Light-switch
• Phenanthroline
• Intercalation
• Photochemistry
• TD-DFT

The photophysics of [Ru(1,10-phenanthroline)2(dipyrido[3,2-1:2’,3’-c]phenazine)]2+ and [Ru(1,10-phenanthroline)2(dipyrido[3,2-1:2’,3’-c]phenazine)]2+•2H2O are investigated by Density Functional and Time-Dependent Density Functional methods. Evidence to support the formation of hydrogen bonds with water in the ground state is presented, and the effects of hydrogen-bonded water on the electronic structure of the complex are described. The excited-state energies were calculated along water-loss reaction coordinates in the ground state and these studies identified specific excited states, with n-to-π* character on both the singlet and triplet hypersurfaces. These are repulsive with respect to the hydrogen-bonding interaction with the phenazine nitrogen atoms. These so-called “drain-pipe” states expel water and proceed to form a “dry” state which is quenched by reaction with bulk water which of course also quenches the luminescence.