Synthesis and Characterization of Cyclooctatetrathiophenes with Different Connection Sequences

Based on the selectivity of deprotonation
of 5,5′-bistrimethylsilyl-2,3′-bithiophene
(4) in the presence of n-BuLi, three
new cyclooctatetrathiophenes (COThs), COTh-1, COTh-2, and COTh-3 have been efficiently
developed via intermolecular or intramolecular cyclizations. Their
crystal structures clearly show that the different connectivity sequence
of the thiophene rings in the molecules. The CV data and UV–vis
absorbance spectra of COThs are also described. In addition,
the time-dependent density functional theory (TDDFT) calculations
accurately reproduce experimental observations and afford band assignment.

基于5,5'-双三甲基硅基-2,3'-联噻吩（5,5′-bistrimethylsilyl-2,3′-bithiophene，化合物4）在正丁基锂（n-BuLi）作用下的去质子化选择性，研究人员通过分子间或分子内环化反应高效合成了三种新型环八四噻吩（cyclooctatetrathiophenes, COThs）：COTh-1、COTh-2与COTh-3。该系列化合物的晶体结构清晰揭示了分子内噻吩环的不同连接序列。此外，本文还报道了COThs的循环伏安法（CV）数据及紫外-可见吸收光谱。进一步通过含时密度泛函理论（time-dependent density functional theory, TDDFT）计算，准确复现了实验观测结果，并完成了能带归属。