کد مقاله | کد نشریه | سال انتشار | مقاله انگلیسی | نسخه تمام متن |
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1316699 | 976474 | 2010 | 9 صفحه PDF | دانلود رایگان |
The photophysical and photochemical properties of the cationic ZnII complex of 5-triethyl ammonium methyl salicylidene ortho-phenylendiimine (ZnL2+) interacting with native DNA were investigated by steady state and time-resolved fluorescence spectroscopies. Experimental results indicate that, in the presence of DNA, ZnL2+ is efficiently protected from a photochemical process, which occurs when it is in the free state dispersed in aqueous solution. The analysis of the absorption and emission spectra of ZnL2+, both stored in the dark and after exposure to tungsten lamp light for 24 h, corroborated by quantum chemical calculations, allowed us to point out that ZnL2+ undergoes a photoinduced two-electron oxidation process. According to this picture, the protective action of DNA toward the intercalated ZnL2+ was attributed to an effective inhibition of the ZnL2+ photooxidation. In this context, it can be considered that DNA-intercalated ZnL2+ is located in a region more hydrophobic than that sensed in the bulk water solvent. Moreover, by a thorough analysis of steady state and time-resolved fluorescence spectra, the interaction process can be consistently explained in terms of a complete intercalation of the complex molecules and that the polarity of the environment sensed by intercalated ZnL2+ is comprised between that of methanol and ethanol.
Graphical AbstractNative DNA prevents the enhancement of the fluorescence intensity of a cationic zinc(II) Salen-type complex exposed to tungsten lamp light. Spectroscopic measurements and quantum chemical calculations point out that DNA protects the intercalated zinc complex from a photoinduced oxidation process.Figure optionsDownload as PowerPoint slide
Journal: Journal of Inorganic Biochemistry - Volume 104, Issue 7, July 2010, Pages 765–773