摘要/Abstract
以“马鞍型”环八四噻吩（COTh）与1，3，5-三嗪为构筑模块，通过Kumada类型反应有效地制备了三种分别含有1～3个COTh结构单元的环八四噻吩-三嗪衍生物，即2，4-二甲氧基-6-（5，8，11-三甲基硅基）-环八[1，2-b：4，3-b'：5，6-b"：8，7-b'"]四噻吩-1，3，5-三嗪（1），2-甲氧基-4，6-二{（5，8，11-三甲基硅基）-环八[1，2-b：4，3-b'：5，6-b"：8，7-b'"]四噻吩}-1，3，5-三嗪（2）和2，4，6-三{（5，8，11-三甲基硅基）-环八[1，2-b：4，3-b'：5，6-b"：8，7-b'"]四噻吩}-1，3，5-三嗪（3）.理论计算表明了该类化合物的长波长的两个吸收峰来自于分子内的电荷转移（CT）吸收.在溶液相它们发射分子内电荷转移（ICT）态荧光，峰位在560～570 nm.而在冻结态下呈双荧光发射，即短波长的环八四噻吩本征态发光（400 nm）与长波长的ICT发光（480～500 nm）.在四氢呋喃（THF）-H2O二元溶剂体系中，该类化合物产生聚集诱导发光（AIE）现象，可能与化合物分子同时受分子内旋转受阻（RIR）与分子内振动受阻（RIV）机制控制有关.单晶数据表明，化合物1分子内噻吩环与三嗪环之间呈现近平面构象.相邻分子之间噻吩环上的碳原子与三嗪环上的碳原子存在C-C相互作用，制约着连接分子内噻吩环与三嗪环之间单键的自由旋转，从而一定程度上制约了非辐射失活过程，有利于AIE现象的产生.
关键词: 环八四噻吩, 1,3,5-三嗪, 晶体结构, 聚集诱导发光
With saddle-shaped cyclooctatetrathiophene (COTh) and 1, 3, 5-triazine as building blocks, three derivatives bearing one, two and three COTh units are synthesized via Kumada-typed reaction. Theoretical calculations indicate that the two absorption peaks in long wavelength region are derived from intramolecular charge transfer (CT) absorption. 2, 4- Di(methoxyl)-6-(5, 8, 11-tris(trimethylsilyl)cycloocta [1, 2-b:4, 3-b':5, 6-b":8, 7-b'"]tetrathiophen-2-yl)-1, 3, 5-triazine (1), 2-meth- oxyl-4, 6-di(5, 8, 11-tris(trimethyl-silyl)cycloocta [1, 2-b:4, 3-b':5, 6-b":8, 7-b'"]tetrathiophen-2-yl)-1, 3, 5-triazine (2) and 2, 4, 6-tris- (5, 8, 11-tris(trimethylsilyl)cycloocta [1, 2-b:4, 3-b':5, 6-b":8, 7-b'"]tetrathiophen-2-yl)-1, 3, 5-triazine (3) exhibit intramolecular charge transfer (ICT) state emission peaked in region of 560～570 nm in solution at room temperature, and give both local emission of COTh peaked at 400 nm and ICT state emission peaked in region of 480～500 nm in rigid solution at 77 K. In tetrahydrofuran (THF)-H2O binary solvent system, compounds 1, 2 and 3 show typical aggregation induced emissions (AIE), which may be controlled by mechanism of restriction of intramolecular rotations (RIR) and restriction of intramolecular vibration (RIV). Crystal structure of 1 shows that intramolecular two rings of triazine and its linked thiophene are planar. There are strong C-C interactions between intermolecular rings of triazine and thiophene, which restrict the intramolecular rotation between triazine and thiophene rings. Such intermolecular C-C interactions are helpful to decrease the process of non-irradiative decay and increase AIE emission.
Key words: cyclooctatetrathiophene, 1, 3, 5-triazine, crystal structure, aggregation induced emission
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