关于钌（II）多吡啶配合物[Ru(bpy)₂(L)]²⁺（L = pip、o - mopip和p - mopip）的DNA光裂解的计算与实验相结合的研究

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).

作者信息

Xu Lian-Cai, Shi Shuo, Li Jun, Liao Si-Yan, Zheng Kang-Cheng, Ji Liang-Nian

机构信息

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.

出版信息

Dalton Trans. 2008 Jan 14(2):291-301. doi: 10.1039/b710546k. Epub 2007 Oct 26.

DOI:10.1039/b710546k

PMID:18097496

Abstract

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 (Ered) 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 Ered (1) < Ered (2) < Ered (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.

摘要

对钌（II）多吡啶配合物[Ru(bpy)2(L)]2+ 1 - 3（bpy = 2,2 - 联吡啶；L：pip = 2 - 苯基咪唑并[4,5 - f]1,10 - 菲咯啉，o - mopip = 2 - (2 - 甲氧基苯基)咪唑并[4,5 - f]1,10 - 菲咯啉，p - mopip = 2 - (4 - 甲氧基苯基)咪唑并[4,5 - f]1,10 - 菲咯啉）的DNA光裂解进行了一项计算与实验相结合的研究。通过凝胶电泳实验对这些配合物的DNA光裂解行为进行了比较测量。实验结果表明，它们能够诱导可观的DNA光裂解，并且具有不同的DNA光裂解效率（φ），顺序为φ(1) < φ(2) < φ(3)。为了理解它们的DNA光裂解机制和趋势，使用密度泛函理论（DFT/TD - DFT）、哈特里 - 福克（HF）和单激发组态相互作用（CIS）方法，对这些配合物在基态（S0）、第一单重激发态（S1）和三重激发态（T1）的几何和电子结构进行了理论研究。特别地，计算出激发态配合物在水溶液中的还原电位（Ered），其似乎与DNA光裂解行为密切相关，配合物1的Ered为0.966 V（相对于SCE），配合物2的为1.024 V（相对于SCE），配合物3的为1.030 V（相对于SCE）。这些计算结果表明，激发态配合物的还原电位达到了氧化一些DNA碱基的理论范围，并且顺序为Ered(1) < Ered(2) < E*red(3)。因此，在此，除了根据我们最近的报告对其DNA光裂解机制进行一般理论解释外，还基于激发态计算的电化学性质以及一般光化学见解，对它们的DNA光裂解效率趋势，即φ(1) < φ(2) < φ(3)，进行了合理的解释。