Xue Pengchong, Sun Jiabao, Yao Boqi, Gong Peng, Zhang Zhenqi, Qian Chong, Zhang Yuan, Lu Ran
State Key Laboratory of Supramolecular, Structure and Materials, College of Chemistry, Jilin University, No. 2699 Qianjin Street, Changchun (China).
Chemistry. 2015 Mar 16;21(12):4712-20. doi: 10.1002/chem.201405074. Epub 2014 Nov 13.
Two L-phenylalanine derivatives with 5,8-bis(2-(carbazol-3-yl)vinyl)quinoxaline (PCQ) and 5,8-bis[2-(carbazol-3-yl)]-2,3-dimethylquinoxaline (DCQ) as fluorophores were synthesized, and their photophysical properties were measured and compared. The two compounds were found to gelate some organic solvents and self-assemble into 1D nanofibers in gels. The wet gel of PCQ emitted a weak orange fluorescence, but the DCQ gel had a strong green one. This result can be due to the presence of two methyl groups and the nonplanar conformation of fluorophore in DCQ. The gel film of DCQ also showed significantly stronger fluorescence than that of PCQ. Thus, the wet gel and xerogel film of DCQ were selected to study their sensing properties to acids. The yellow wet gel of DCQ transformed into a brown sol upon the addition of 0.2 equiv trifluoroacetic acid (TFA), accompanied by emission quenching. The xerogel film of DCQ rapidly responded to volatile acids, such as TFA, HCl, and HOAc. The fluorescence of the xerogel film was gradually quenched with increased concentration of volatile acid vapors. The fibrous film exhibited low detection limits for volatile acid. The detection limits of the thin films for TFA, HCl, and HOAc reached 43, 122, and 950 ppb, respectively.
合成了两种以5,8-双(2-(咔唑-3-基)乙烯基)喹喔啉(PCQ)和5,8-双[2-(咔唑-3-基)]-2,3-二甲基喹喔啉(DCQ)为荧光团的L-苯丙氨酸衍生物，并对其光物理性质进行了测量和比较。发现这两种化合物能使一些有机溶剂凝胶化，并在凝胶中自组装成一维纳米纤维。PCQ的湿凝胶发出微弱的橙色荧光，但DCQ凝胶发出强烈的绿色荧光。这一结果可能是由于DCQ中存在两个甲基以及荧光团的非平面构象。DCQ的凝胶膜也显示出比PCQ的凝胶膜更强的荧光。因此，选择DCQ的湿凝胶和干凝胶膜来研究它们对酸的传感特性。加入0.2当量的三氟乙酸(TFA)后，DCQ的黄色湿凝胶转变为棕色溶胶，同时伴随着发射猝灭。DCQ的干凝胶膜对挥发性酸，如TFA、HCl和HOAc有快速响应。随着挥发性酸蒸汽浓度增加，干凝胶膜的荧光逐渐猝灭。纤维膜对挥发性酸表现出低检测限。薄膜对TFA、HCl和HOAc的检测限分别达到43、122和950 ppb。
