Immobilization of pyrene on quartz plate surface via a flexible long spacer and its sensing properties to dicarboxylic acids
Immobilization of pyrene on quartz plate surface via a flexible long spacer and its sensing properties to dicarboxylic acids
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DOI：
10.1360/03yb0072
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发表时间：
2004-03
影响因子：
9.6
通讯作者：
Lining Gao;Fang Yu;Feng-Ting Lu;Liping Ding
中科院分区：
文献类型：
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作者：
Lining Gao;Fang Yu;Feng-Ting Lu;Liping Ding
采用柔性长间隔层、1，3-丙二胺和3-环氧丙氧丙基三甲氧基硅烷将芘固定在石英片表面，制备了一种新型的光致发光薄膜。该膜显示了芘在湿态和干态下的单体和激基缔合物的组合发射。稳态和时间分辨荧光光谱的测量结果表明，激基缔合物的荧光主要来自于基态二聚体和/或聚集态单体的直接激发。经典的Birks方案在准分子的形成过程中起的作用很小。在激发过程中形成的准分子的结构是复杂的。在荧光团的激发态，既有类双链完全重叠结构的“标准激基缔合物”，又有部分重叠结构的“畸变激基缔合物”。薄膜的发光对二元酸的存在敏感，二元酸包括乙二酸、丙二酸、丁二酸等。单体和激基缔合物区的发光随二元酸浓度的增加沿着增加。排放达到平衡所需的时间取决于酸的性质。已经表明，酸的链长越长，所需的时间越长。这一观察解释考虑到固定化芘的构象重组，由于插入的二羧酸到相邻的间隔子之间的空间。使用甲酸和乙酸的类似研究的实验结果支持这一解释。此外，膜对二羧酸的响应是可逆的。
A novel photo-induced luminescence film has been prepared by immobilizing pyrene on quartz plate surface via a flexible long spacer, 1,3-diaminopropane and 3-glycidoxypropyl trimethoxysilane. The film shows combined monomer and excimer emission of pyrene in both wet and dry states. Steady-state and time-resolved fluorescence emission measurements demonstrated that the excimer emission mainly came from direct excitation of ground state dimers, and/or monomers in aggregated state. Classical Birks’ scheme plays little role in the formation of the excimers. The structures of the excimers formed during the excitation are complex. Both “standard excimer” of sandwich-like fully overlapped structure and ‘distorted excimer” of partially overlapped structure exist in the excited state of the fluorophore. The emission of the film is sensitive to the presence of dicarboxylic acids, including ethanedioic acid, malonic acid, succinic acid, etc. The emission in the monomer and excimer region increases along with increasing the concentration of the dicarboxylic acids. The time needed for the emission to reach equilibrium depends on the nature of the acids. It has been shown that the longer the chain length of the acids, the more the time needed. This observation is explained by considering the conformational reorganization of the immobilized pyrene due to insertion of the dicarboxylic acids into the space between neighboring spacers. Experimental results from similar studies using formic acid and acetic acid are in support of this explanation. Furthermore, the response of the film to dicarboxylic acids is reversible.