Theoretical studies on the spectral and DNA-photocleavage properties of Co(III) and Ru(II) polypyridyl complexes

Theoretical studies on the spectral and DNA-photocleavage properties of Co(III) and Ru(II) polypyridyl complexes [M(phen)2(pyip)]n+ (M = Co(III) and Ru(II), n = 3 and 2, respectively) have been carried out, using DFT, HF and CIS methods. The electronic absorption spectra of the two complexes were calculated and simulated using TDDFT and CPCM model. The calculated results show that both the geometric structure and spectra of the Co(III) complex are greatly affected by the solvent effect, whereas those of the Ru(II) complex are affected only slightly by the solvent effect. The calculated and simulated spectra of these complexes in solution are in satisfying agreement with experimental ones, and the characters of the interested spectral bands are deeply discussed. In addition, the photo-induced oxidation-reduction mechanisms on the DNA-photocleavage by Co(Ш) and Ru(II) polypyridyl complexes are also preliminarily explained in theory.