The interaction of the excited states of safranine-O with low generation carboxyl terminated PAMAM dendrimers in an aqueous medium,Photochemical & Photobiological Sciences

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The interaction of the excited states of safranine-O with low generation carboxyl terminated PAMAM dendrimers in an aqueous medium
Photochemical & Photobiological Sciences ( IF 2.7 ) Pub Date : 2018-04-11 00:00:00 , DOI: 10.1039/c8pp00039e
M. Paula Militello _{1,

2,

3,

4} , Marcela S. Altamirano _{1,

2,

3,

4} , Sonia G. Bertolotti _{1,

2,

3,

4} , Carlos M. Previtali _{1,

2,

3,

4}

Affiliation

The interaction of the singlet and triplet excited states of the synthetic dye safranine-O with carboxyl-terminated poly(amidoamine) (PAMAM) dendrimers was investigated in a buffer solution at pH 8. Low half-generation PAMAM dendrimers (G −0.5; G +0.5: G 1.5) were employed. The UV-vis absorption spectrum of the dye presents only a very small red shift in the presence of dendrimers. Fluorescence quenching was detected and it was interpreted by a static mechanism in terms of the association of the dye with the dendrimer. Laser flash photolysis experiments were carried out and transient absorption spectra of the triplet and radicals were obtained. The triplet state is quenched by the dendrimers with rate constants well below the diffusional limit. The quenching process was characterized as an electron transfer process and the quantum yield of radicals was estimated. It was found that radicals are formed with a high efficiency in the triplet quenching reaction.

中文翻译：

藏红素-O的激发态与低级羧基封端的PAMAM树状大分子在水性介质中的相互作用

在pH值为8的缓冲溶液中研究了合成染料藏红花O的单重态和三重态激发态与羧基端接的聚（酰胺基胺）（PAMAM）树枝状聚合物的相互作用。 +0.5：G 1.5）。在存在树枝状聚合物的情况下，染料的UV-vis吸收光谱仅表现出很小的红移。检测到荧光猝灭，并通过静态机理将其解释为染料与树枝状聚合物的缔合。进行了激光闪光光解实验，获得了三重态和自由基的瞬态吸收光谱。三重态被树枝状聚合物淬灭，其速率常数远低于扩散极限。淬灭过程的特征是电子转移过程，并估计了自由基的量子产率。发现在三重态猝灭反应中高效形成自由基。

更新日期：2018-04-11

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