Optically active BINOL core-based phenyleneethynylene dendrimers for the enantioselective fluorescent recognition of amino alcohols.
Optically active BINOL core-based phenyleneethynylene dendrimers for the enantioselective fluorescent recognition of amino alcohols.
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DOI：
10.1021/jo010479t
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发表时间：
2001-08
期刊：
影响因子：
--
通讯作者：
V. J. Pugh;Q. Hu;X. Zuo;F. Lewis;L. Pu
中科院分区：
文献类型：
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作者：
V. J. Pugh;Q. Hu;X. Zuo;F. Lewis;L. Pu
观察到从1,1'-双-2-萘酚（BINOL）到含有BINOL核心的树突状苯乙烯的荧光强度显著增强。树状大分子的强荧光使得极少量的手性材料可以用于传感。树状分子的光收集天线将能量漏斗到中心BINOL单元，BINOL单元的羟基与猝灭分子相互作用导致荧光猝灭。这种机制使得树状大分子比相应的小分子传感器具有更灵敏的荧光响应。这些树状大分子的荧光可被手性氨基醇对映选择性猝灭。观察到，在不同浓度的2-氨基-3-苯基-1-丙醇存在下，第二代树状大分子的荧光寿命没有变化。这表明荧光猝灭完全是由于静态猝灭。因此，树状大分子和氨基醇之间的非荧光基态氢键配合物的形成被提出来解释荧光猝灭。第二代树状大分子的Stern-Völmer常数与2-氨基-3-苯基-1-丙醇的对映体组成之间建立了线性关系。这种对映体选择性荧光传感器可以快速测定手性分子的对映体组成，并且在不对称催化剂和试剂的组合搜索中具有潜在的用途。
A dramatic enhancement in fluorescence intensity from 1,1'-bi-2-naphthol (BINOL) to dendritic phenyleneethynylenes containing the BINOL core was observed. The strong fluorescence of the dendrimers allows a very small amount of the chiral materials to be used for sensing. The light harvesting antennas of the dendrimer funnel energy to the center BINOL unit, whose hydroxyl groups upon interaction with a quencher molecule lead to fluorescence quenching. This mechanism makes the dendrimers have much more sensitive fluorescence responses than corresponding small molecule sensors. The fluorescence of these dendrimers can be enantioselectively quenched by chiral amino alcohols. It is observed that the fluorescence lifetime of the generation two dendrimer does not change in the presence of various concentrations of 2-amino-3-phenyl-1-propanol. This demonstrates that the fluorescence quenching is entirely due to static quenching. Thus, formation of nonfluorescent ground-state hydrogen-bond complexes between the dendrimers and amino alcohols is proposed to account for the fluorescent quenching. A linear relationship has been established between the Stern-Völmer constant of the generation two dendrimer and the enantiomeric composition of 2-amino-3-phenyl-1-propanol. Such enantioselective fluorescent sensors may allow a rapid determination of the enantiomeric composition of chiral molecules and are potentially useful in the combinatorial search of asymmetric catalysts and reagents.