Experimental and Theoretical Studies on DNA‐Binding and Spectral Properties of ‘Light Switch’ Complexes [Ru(L)2(ppn)]2+ (L=2,2′‐Bipyridine and 1,10‐Phenanthroline; ppn=Pteridino[6,7‐f] [1,10]phenanthroline‐11,13‐diamine) |
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Authors: | Xue‐Wen Liu Jin‐Can Chen Xia Hu Hong Li Kang‐Cheng Zheng Liang‐Nian Ji |
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Institution: | 1. The Key Laboratory of Bioinorganic and Synthetic Chemistry of Ministry of Education/School of Chemistry and Chemical Engineering, Sun Yat‐Sen University, Guangzhou 510275, P.?R. China, (phone: +86‐20‐84110696;2. fax: +86‐20‐84112245 (K.‐C.?Z.), (L.‐N.?J.));3. Department of Chemistry and Chemical Engineering, Hunan University of Arts and Science, ChangDe 415000, P.?R. China;4. Department of Chemistry, Southern China Normal University, Guangzhou 510000, P.?R. China |
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Abstract: | The ligand pteridino6,7‐f] 1,10]phenanthroline‐11,13‐diamine (ppn) and its RuII complexes Ru(bpy)2(ppn)]2+ ( 1 ; bpy=2,2′‐bipyridine) and Ru(phen)2(ppn)]2+ ( 2 ; phen=1,10‐phenanthroline) were synthesized and characterized by elemental analysis, electrospray MS, 1H‐NMR, and cyclic voltammetry. The DNA‐binding behaviors of 1 and 2 were studied by spectroscopic and viscosity measurements. The results indicate that both complexes strongly bind to calf‐thymus DNA in an intercalative mode, with DNA‐binding constants Kb of (1.7±0.4)?106 M ?1 and (2.6±0.2)?106 M ?1, respectively. The complexes 1 and 2 exhibit excellent DNA‐‘light switch’ performances, i.e., they do not (or extremely weakly) show luminescence in aqueous solution at room temperature but are strongly luminescent in the presence of DNA. In particular, the experimental results suggest that the ancillary ligands bpy and phen not only have a significant effect on the DNA‐binding affinities of 1 and 2 but also have a certain effect on their spectral properties. Ru(phen)2(ppn)]2+( 2 ) might be developed into a very prospective DNA‐‘light switch’ complex. To explain the DNA‐binding and spectral properties of 1 and 2 , theoretical calculations were also carried out applying the DFT/TDDFT method. |
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Keywords: | Ruthenium complexes 2 2′ ‐Bipyridine 1 10‐Phenanthroline ‘ Light switch’ complexes DNA Binding Pteridino[6 7‐f] [1 10]phenanthroline‐11 13‐diamine |
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