Theoretical studies on DNA-photocleavage efficiency and mechanism of functionalized Ru(II) polypyridyl complexes.

Theoretical studies on the DNA-photocleavage mechanism and efficiency of some Ru(II) polypyridyl complexes as novel reagents have been carried out using the density functional theory (DFT) method. Stable DNA-docking models of Ru(II) polypyridyl complexes were obtained using the docking and DFT methods. The excited-state reduction potentials, electron-transfer (ET) activation energies, and intramolecular reorganization energies were theoretically calculated, and the corresponding frontier molecular orbitals of complexes were also presented. Based on these properties of excited states, the essential component of two different DNA-photocleavage mechanisms, i.e., the photoinduced oxidation-reduction mechanism and the singlet oxygen photosensitization mechanism, has been revealed, and the DNA-photocleavage efficiencies were reasonably explained, and hereby a complex with excellent DNA-photocleavage ability was also designed. This work offers valuable theoretical insight into the property of excited-states and the DNA-photocleavage mechanism of Ru(II) polypyridyl complexes as novel reagents.