A combined computational and experimental study on DNA-photocleavage of Ru(II) polypyridyl complexes [Ru(bpy)2(L)]2+ (L = pip, o-mopip and p-mopip).
A combined computational and experimental study on DNA-photocleavage by Ru(II) polypyridyl complexes [Ru(bpy)2(L)]2+ 1-3 (bpy = 2,2-bipyridine; L: pip = 2-phenylimidazo[4,5-f]1,10-phenanthroline, o-mopip = 2-(2-methoxyphenyl)imidazo[4,5-f]1,10-phenanthroline and p-mopip = 2-(4-methoxyphenyl)imidazo[4,5-f]1,10-phenanthroline) has been carried out. The DNA-photocleavage behavior of these complexes was comparably measured by the gel electrophoresis experiments. The experimental results show that they can induce considerable DNA-photocleavage, and have different DNA-photocleavage efficiencies (phi) following the order phi (1) < phi (2) < phi (3). In order to understand their DNA-photocleavage mechanism and trend, the theoretical studies on the geometric and electronic structures of these complexes in the ground state (S0), the first singlet excited state (S1) and triplet excited states (T1), have been carried out using the density functional theory (DFT/TD-DFT), Hartree-Fock (HF) and configuration interaction singles (CIS) methods. In particular, the reduction potentials (E*red) of the excited complexes in aqueous solution, which seem to be closely responsible for the DNA-photocleavage behavior, were calculated to be 0.966 V (vs. SCE) for complex , 1.024 V (vs. SCE) for complex and 1.030 V (vs. SCE) for complex , respectively. Such computational results show that the reduction potentials of the excited complexes reach the theoretical range for oxidizing some DNA-bases, and follow the order E*red (1) < E*red (2) < E*red (3). Therefore, here, in addition to the general theoretical explanation of their DNA-photocleavage mechanism according to our recent report, a further explanation on the trend of their DNA-photocleavage efficiencies, i.e., phi (1) < phi (2) < phi (3), was reasonably carried out, on the basis of the calculated electrochemical properties in the excited states as well as general photochemical insights.
Xu
Lian-Cai
LC
The Key Laboratory of Bioinorganic and Synthetic Chemistry of Ministry of Education, School of Chemistry and Chemical Engineering, Sun Yat-Sen University, Guangzhou, 510275, PR China.
Shi
Shuo
S
Li
Jun
J
Liao
Si-Yan
SY
Zheng
Kang-Cheng
KC
Ji
Liang-Nian
LN
D015082:2,2'-Dipyridyl / Q000737:chemistry*; D020650:Combinatorial Chemistry Techniques; D004247:DNA / Q000737:chemistry*; D004563:Electrochemistry; D007202:Indicators and Reagents; D008958:Models, Molecular; D008968:Molecular Conformation; D009942:Organometallic Compounds / Q000737:chemistry*; D010084:Oxidation-Reduction; D010618:Phenanthrolines / Q000737:chemistry*; D010777:Photochemistry; D012413:Rubidium / Q000737:chemistry*; D012996:Solutions; D013816:Thermodynamics
D007202:Indicators and Reagents; D009942:Organometallic Compounds; D010618:Phenanthrolines; D012996:Solutions; C526881:phenylimidazo(4,5-f)1,10-phenanthroline; C474863:ruthenium(bipyridyl)(2)-2-(2-hydroxyphenyl)imidazo(4,5-f)(1,10)phenanthroline; D015082:2,2'-Dipyridyl; D004247:DNA; D012413:Rubidium