Enhancement of energy utilization in light-harvesting dendrimers by the pseudorotaxane formation at periphery.
Enhancement of energy utilization in light-harvesting dendrimers by the pseudorotaxane formation at periphery.
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DOI：
10.1021/ja902998g
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发表时间：
2009-05
影响因子：
15
通讯作者：
Yi Zeng;Yingying Li;Ming Li;Guoqiang Yang;Yi Li
中科院分区：
文献类型：
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作者：
Yi Zeng;Yingying Li;Ming Li;Guoqiang Yang;Yi Li
合成了一系列水溶性萘末端修饰树状大分子G0-3NapH。荧光研究表明，在这些树突状分子中，外围发色团之间发生了强相互作用，这是因为它们具有强烈的准分子发射和低荧光量子产率（G0-3NapH的Phi(f)分别为0.12、0.097、0.065和0.062）。通过树突状分子与葫芦[7]uril （CB[7]）的组装，形成了定义良好的伪烷组装体GnNapH x xCB[7] (n = 0-3时分别为x = 4,8,16,32)，并完全抑制了能量耗散，导致树突状分子的荧光量子产率急剧增加（0-3代时分别为Phi(f) = 0.18, 0.19, 0.19和0.20）。非共价修饰是一个可逆过程，加入1-氨基金刚烷可以使CB[7]脱离树突外周，与CB[7]形成更稳定的配合物。在此基础上，将能量受体9-蒽甲酸（AN）引入树突体系，研究其能量利用情况。稳态荧光研究表明，在G3NapH x 32 CB[7]-AN和G2NapH x 16 CB[7]-AN中，萘基到AN的能量转移效率比没有CB[7]络合的情况下分别提高了100%和70%。该研究为开发可控的光收集或发光树突系统提供了一种新的策略。
A series of water-soluble naphthyl terminal-decorated dendrimers G0-3NapH were synthesized. Fluorescence studies reveal that strong interactions among peripheral chromophores occur in these dendrimers according to the intensive excimer emission and the low fluorescence quantum yields (Phi(f) = 0.12, 0.097, 0.065, and 0.062 for G0-3NapH). Through assembly of dendrimer with cucurbit[7]uril (CB[7]), the well-defined pseudorotaxane assemblies GnNapH x xCB[7] (x = 4, 8, 16, 32 for n = 0-3, respectively) form and the energy dissipation is entirely suppressed, resulting in a dramatic increase of the fluorescence quantum yields of dendrimers (Phi(f) = 0.18, 0.19, 0.19, and 0.20 for 0-3 generations, respectively). The noncovalent modification is a reversible process, and CB[7] can be unthreaded from the dendrimer periphery by adding 1-amimoadamantane, which can form a more stable complex with CB[7]. Furthermore, 9-anthracenecarboxylic acid (AN), an energy acceptor, was introduced into the dendritic system to investigate the harvested energy utilization. Steady-state fluorescence investigations demonstrate that the energy transfer efficiencies from naphthyl to AN in G3NapH x 32 CB[7]-AN and G2NapH x 16 CB[7]-AN are enhanced 100 and 70% compared with those without CB[7] complexation. This study provides a new strategy for developing controllable light-harvesting or -emitting dendritic systems.