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首页> 外文会议>Conference on reporters, markers, dyes, nanoparticles, and molecular probes for biomedical applications >Aggregation induced enhanced emission in Dimethyl-2,5-bis(4-methoxyphenylamino)terephthalate
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Aggregation induced enhanced emission in Dimethyl-2,5-bis(4-methoxyphenylamino)terephthalate

机译：聚集诱导二甲基-2,5-双（4-甲氧基苯基氨基）对苯二甲酸酯的增强发射

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Dimethyl-2,5-bis(4-methoxyphenylamino)terephthalate (1) exhibits very feeble emission in acetone solution, but is strongly emissive in the solid state. In order to develop an understanding of the processes responsible for such behavior, fluorescence studies have been performed on solutions of 1 in acetone-water mixtures. Increase in water content of these solutions is found to result in broadening of the absorption spectra along with red shift of the absorption maximum, suggesting the formation of aggregates. The process of aggregation is associated with a significant enhancement of the emission intensity. This is a manifestation of the aggregation induced enhanced emission (AIEE) phenomenon. Quantum chemical calculations reveal a propeller-like shape of the molecule, which is an essential criterion for AIEE-active molecules. The major nonradiative relaxation of the excited state of this molecule is likely to involve the rotation of the molecular segments with respect to each other. X-ray diffraction studies reveal a stacking pattern, which is likely to hinder such nonradiative decativation of the excited state, leading to the enhanced emission in solid state and aggregated state of the molecule. The trend of variation of emission intensity, as a function of water content of the mixture, is in line with the size of aggregates formed in these mixtures, as is brought out by light scattering studies. Electron microscopy reveals that the microstructure of the aggregates as well as the solid powder of 1 consists of nanorods. Fluorescence lifetimes indicate that the nature of the emissive species in the aggregates and the solid is the same. Thus, a systematic understanding of the structure and photoprocesses in the aggregates is developed.
机译：二甲基-2,5-双（4-甲氧基苯基氨基）对苯二甲酸酯（1）在丙酮溶液中表现出非常微弱的发射，但在固态中强烈发射。为了制定对负责这种行为的过程的理解，已经对丙酮 - 水混合物中的1溶液进行了荧光研究。发现这些溶液的含水量的增加导致吸收光谱随着吸收最大的红色转变而导致吸收光谱，表明聚集体的形成。聚集过程与发射强度的显着增强相关。这是聚集诱导增强发射（AIEE）现象的表现形式。量子化学计算揭示了分子的螺旋桨形状，这是AIEE-活性分子的必要标准。该分子的激发态的主要非辐射弛豫可能涉及分子段相对于彼此的旋转。 X射线衍射研究揭示了一种堆叠图案，其可能阻碍激发态的这种非抗想，导致固态和分子聚集状态的增强发射。发射强度变化的趋势，作为混合物的水含量的函数，符合这些混合物中形成的聚集体的尺寸，如光散射研究所带来的那样。电子显微镜揭示了聚集体的微观结构以及1的固体粉末由纳米棒组成。荧光寿命表明聚集体中发光物种的性质和固体是相同的。因此，开发了对聚集体中结构和光处理的系统理解。

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