Energy transfer in dendritic macromolecules: Molecular size effects and the role of an energy gradient
Energy transfer in dendritic macromolecules: Molecular size effects and the role of an energy gradient
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DOI：
10.1021/ja961418t
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发表时间：
1996-10-09
影响因子：
15
通讯作者：
Moore, JS
中科院分区：
文献类型：
--
作者：
Devadoss, C;Bharathi, P;Moore, JS
合成了二萘嵌苯封端的单枝分子1-7和苯基封端的参比单枝分子8-14，并使用稳态和时间分辨荧光光谱研究了分子内能量转移。在系列2-7中，由于摩尔消光系数的增加，这些化合物的捕光能力随着代的增加而增加。然而，在该系列中，能量传递的效率随着发电量的增加而降低。随着生成的增加，来自二萘嵌苯核的光致发光强度仍然增加，并且在这一系列化合物中尚未达到光致发光强度的预期平稳。树枝状聚合物1的独特之处在于该分子中的能量转移速度非常快。1中的能量转移速率常数比2-7中的至少大2个数量级。与monodendron 2-7相反，1在每一代都具有可变的单体类型，这产生了能量漏斗。在这个系统中的超快能量转移是最好的解释，这种能量梯度的存在。
Perylene-terminated monodendrons 1-7 and phenyl-terminated reference monodendrons 8-14 have been synthesized, and the intramolecular energy transfer has been studied using steady-state as well as time-resolved fluorescence spectroscopy. In the series 2-7, the light-harvesting ability of these compounds increases with increasing generation due to the increase in molar extinction coefficient. However, the efficiency of the energy transfer decreases with increasing generation in this series. With increasing generation, the photoluminescence intensity from the perylene core still increases and the expected level-off in the photoluminescence intensity has not been reached in this series of compounds. Dendrimer 1 is unique in that the energy transfer in this molecule occurs at a very fast rate. The rate constant for energy transfer in 1 is at least 2 orders of magnitude larger than in 2-7. In contrast to monodendrons 2-7, 1 possesses a variable monomer type at each generation that creates an energy funnel. The ultrafast energy transfer in this system is best explained by the presence of this energy gradient.