Luminescence quenching of ruthenium(II)-tris(phenanthroline) by cobalt(III)-tris(phenanthroline) bound to the surface of starburst dendrimers
Luminescence quenching of ruthenium(II)-tris(phenanthroline) by cobalt(III)-tris(phenanthroline) bound to the surface of starburst dendrimers
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DOI：
10.1021/jp980135f
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发表时间：
1998-06-25
影响因子：
3.3
通讯作者：
Turro, NJ
中科院分区：
文献类型：
--
作者：
ben-Avraham, D;Schulman, LS;Turro, NJ
统计分析了[Co(phen)(3)]（3+）对光激发敏化剂[Ru(phen)(3)]（2+）在星爆树突状多阴离子（SBD代3.5 ~ 6.5）表面的猝灭作用。我们的分析是基于之前为DNA的“一维”情况开发的随机沉积模型的扩展。我们的目标是推导出在淬火过程中光电子转移的相互作用距离(L)特征。统计分析得出了令人惊讶的结果，电子供体和受体金属配合物并不是随机结合在SBD表面上，而是倾向于彼此相邻。在所有四代被测试的树状大分子中，吸引能量epsilon近似于2.9k(B)T，几乎是相等的。我们认为这种吸引力源于疏水相互作用。敏化剂和受体的聚类导致发光猝灭的增加，在没有本分析的情况下（特别是在随机结合的假设下），这可能被错误地归因于更长的电子转移范围。
We have conducted a statistical analysis of luminescence quenching of the photoexcited sensitizer [Ru(phen)(3)](2+) by [Co(phen)(3)](3+) on the surface of starburst dendrimer polyanions (SBD generations 3.5-6.5). Our analysis is based on an extension of the random-deposition model, previously developed for the "one-dimensional" case of DNA. Our goal is to deduce the interaction distance (L) characteristic of the photoelectron transfer in the quenching process. The statistical analysis yields the surprising result that the electron donor and acceptor metal complexes do not bind randomly on the SBD's surfaces but that they tend to be found next to one another. The energy of attraction, epsilon approximate to 2.9k(B)T, is nearly equal for all four generations of dendrimers tested. We argue that the attraction stems from hydrophobic interactions. The clustering of sensitizers and accepters results in an increase of luminescence quenching which in the absence of the present analysis (and in particular with a random binding assumption) might erroneously have been attributed to a longer range of electron transfer.