Theoretical studies on DNA-photocleavage efficiencies of Ru(ii) polypyridyl complexes

Abstract

Theoretical studies on the DNA-photocleavage efficiencies of Ru(II) polypyridyl complexes 1–4 have been carried out using density functional theory (DFT). First, an evaluation of the computational accuracy of the redox potentials for [Ru(bpy)₃]²⁺ in the ground state and the excited state was tested by different computational methods. Secondly, the redox potentials of complexes 1–4 in the excited state were accurately computed. Finally, the trend in the DNA-photocleavage efficiencies (ϕ) of complexes 1–4, i.e., ϕ(4) > ϕ(3) > ϕ(2) > ϕ(1), were reasonably explained by the excited-state reduction potentials and the electron-transfer activation energies. In particular, the DNA-photocleavage efficiencies of two new Ru(II) complexes 3 and 4 were predicted.