[Ru(MeIm)4L]2+ (L=iip, tip, 2ntz)的电子结构、DNA-键合、构效关系及光谱特征

采用密度泛函的方法，结合导体极化连续模型研究了水溶性二价钌-甲基咪唑类配合物Ru(MeIm)₄iip]²⁺ (1)、Ru(MeIm)₄tip]²⁺(2)和Ru(MeIm)₄2ntz]²⁺ (3)的电子结构、DNA的键合倾向及构效关系．在水溶液中几何优化的基础上分析了配合物的电子结构特征，并合理解释了配合物与DNA的键合倾向．计算结果表明，在主配体上用噻吩代替咪唑取代基可以有效提高配合物与DNA的键合力；同时，在主配体的骨架上引入强电负性的N原子及NO₂基团可以明显降低配合物最低未占据分子轨道能量及前沿分子轨道能量差．基于以上计算结果，预测所设计的配合物3具有最大的DNA键合力常数．另外，详细分析了配合物1、2的构效关系及抗肿瘤作用机理，并预测了配合物3的抗肿瘤活性．最后，用含时密度泛函方法对配合物的电子吸收光谱进行了计算和模拟，并与实验结果进行了对比分析.

Electronic Structures, DNA-binding, SAR, and Spectral Properties of Ruthenium Methylimidazole Complexes [Ru(MeIm)4L]2+ (L=iip, tip, 2ntz)

Theoretical studies on the electronic and geometric structures, the trend in DNA-binding affinities as well as the the structure-activity relationship (SAR) of a series of water-soluble Ru(II) methylimidazole complexes, i.e. Ru(MeIm)₄iip]²⁺ (1) (MeIm=1-methylimidazole, iip=2-(1H-imidazo-4-group)-1H-imidazo4,5-f]1,10]phenanthroline), Ru(MeIm)₄tip]²⁺ (2) (tip=2-(thiophene-2-group)-1H-imidazo4,5-f]1,10]phenanthroline), and Ru(MeIm)₄2ntz]²⁺ (3) (2ntz=2-(2-nitro-1,3-thiazole-5-group)-1H-imidazo4,5-f]1,10]phenanthroline), were car-ried out using the density functional theory (DFT). The electronic structures of these Ru(II) complexes were analyzed on the basis of their geometric structures optimized in aqueous solution, and the trend in the DNA-binding constants (K_b) was reasonably explained. The results show that the replacement of imidazole ligand by thiophene ligand can effectively improve the DNA-binding affinity of the complex. Meanwhile, it was found that introduc-ing the stronger electronegative N atom and NO₂ group on terminal loop of intercalative ligand can obviously reduce the complex's LUMO and HOMO-LUMO gap energies. Based on these findings, the designed complex Ru(MeIm)₄2ntz]²⁺ (3) can be expected to have the greatest K_b value in complexes 1-3. In addition, the structure-activity relationships and antitumor mechanism were also carefully discussed, and the antimetastatic activity of the designed complex 3 was predicted. Finally, the electronic absorption spectra of this series of complexes in aqueous solution were calculated, simulated and assigned using DFT/TDDFT methods as well as conductor-like polarizable continuum model (CPCM), and were in good agreement with the experimental results.