Theoretical insights and design of Ru(II)-based complexes with DNA-photocleavage properties

A theoretical research on the properties of Ru(II)-based complexes 1–5 with polypyridyl ligands damaging DNA with the help of light has been carried out. Firstly, the redox potential, electrons-transfer (ET) activation energy, and intra-molecular reorganization energy were computed using DFT (density functional theory), and the results can be used to explain the DNA-photocleavage efficiencies of complexes. Secondly, the effect of ligands on the reduction potentials of complexes in the excited state was elucidated, and the reason of complexes cleaving DNA by the oxidation-reduction reaction and the produced singlet oxygen was explained. Finally, the frontier orbitals of complexes were computed, which was used to qualitatively explain the reason of complexes with high reduction potentials in the excited state.