Experimental and DFT studies on the DNA-binding trend and spectral properties of complexes [Ru(bpy)₂L]²⁺ (L = dmdpq, dpq, and dcdpq)

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• 作者：Xue W. Liu ; Jun Li ; Hong Deng ; Kang C. Zheng ; Zong W. Mao and Liang N. Ji
• 关键词：Ru(II) complex ; DNA-binding ; Spectral property ; Intercalation mode ; DFT calculation
• 刊名：Inorganica Chimica Acta
• 出版年：2005
• 出版时间：2005
• 年：2005
• 卷：358
• 期：12
• 页码：3311-3319
• 全文大小：356 K

文摘

The trend in DNA-binding affinities and the spectral properties of a series of Ru(II) polypyridyl complexes, [Ru(bpy)₂(dmdpq)]²⁺ (1), [Ru(bpy)₂(dpq)]²⁺ (2), [Ru(bpy)₂(cndpq)]²⁺ (3) (bpy = 2,2′-bipyridine; dpq = dipyrido[3,2-d:2′,3′-f]quinoxaline; dmdpq = di-methyl-dpq; dcdpq = di-cyano-dpq), have been experimentally and theoretically investigated. The DNA-binding constants K_b of the complexes were determined systematically with spectrophotometric titration. The density functional theory (DFT) and time-dependent DFT (TDDFT) calculations were carried out for these complexes. The experimental results show that these complexes bind to DNA in intercalation mode, and the order of their intrinsic DNA-binding constants K_b is K_b(1) < K_b(2) K_b(3). The substituents on the intercalative ligands of the complexes play a very important role in the control of DNA-binding affinities of the complexes, in particular, the stronger electron-withdrawing substituent (–CN) on the intercalative ligand can greatly improve the DNA-binding property of the derivative complex. The trend in DNA-binding affinities as well as the spectral properties of metal–ligand charge-transition (¹MLCT) of this series of complexes can be reasonably explained by applying the DFT and TDDFT calculations and the frontier molecular orbital theory.