Department of Chemistry, University of North Carolina at Charlotte , Charlotte, North Carolina 28223, United States.
J Am Chem Soc. 2017 Jun 28;139(25):8467-8473. doi: 10.1021/jacs.7b01005. Epub 2017 Jun 2.
The synthesis, electrochemical, and photophysical characterization of N,N'-dialkylated and N,N'-dibenzylated dipyridinium thiazolo[5,4-d]thiazole derivatives are reported. The thiazolothiazole viologens exhibit strong blue fluorescence with high quantum yields between 0.8-0.96. The dioctyl, dimethyl, and dibenzyl derivatives also show distinctive and reversible yellow to dark blue electrochromism at low reduction potentials. The fused bicyclic thiazolo[5,4-d]thiazole heterocycle allows the alkylated pyridinium groups to remain planar, strongly affecting their electrochemical properties. The singlet quantum yield is greatly enhanced with quaternarization of the peripheral 4-pyridyl groups (Φ increases from 0.22 to 0.96) while long-lived fluorescence lifetimes were observed between 1.8-2.4 ns. The thiazolothiazole viologens have been characterized using cyclic voltammetry, UV-visible absorbance and fluorescence spectroscopy, spectroelectrochemistry, and time-resolved photoluminescence. The electrochromic properties observed in solution, in addition to their strong fluorescent emission properties, which can be suppressed upon 2 e reduction, make these materials attractive for multifunctional optoelectronic, electron transfer sensing, and other photochemical applications.
本文报道了 N,N'-二烷基化和 N,N'-二苄基化二吡啶并噻唑[5,4-d]噻唑衍生物的合成、电化学和光物理特性。噻唑并噻唑紫精表现出强的蓝色荧光，量子产率在 0.8-0.96 之间。二辛基、二甲基和二苄基衍生物在低还原电位下也表现出独特且可逆的黄色到深蓝色电致变色。稠合的双环噻唑[5,4-d]噻唑杂环使烷基化的吡啶鎓基团保持平面，强烈影响其电化学性质。卟啉化的外围 4-吡啶基基团的单线态量子产率大大提高（从 0.22 增加到 0.96），同时观察到 1.8-2.4 ns 之间的长寿命荧光寿命。噻唑并噻唑紫精已通过循环伏安法、紫外-可见吸收和荧光光谱法、光谱电化学和时间分辨光致发光进行了表征。在溶液中观察到的电致变色性质，以及其强烈的荧光发射性质（可通过 2e 还原抑制），使这些材料在多功能光电、电子转移传感和其他光化学应用中具有吸引力。
