Diarylethene-based xerogels: the fabrication of more entangled networks driven by isomerization and acidofluorochromism. Issue 12 (7th March 2018)

• Record Type: Journal Article
• Authors: Wang, Haoran; Zhao, Jinyu; Yang, Guojian; Zhang, Fushuang; Sun, Jingbo; Lu, Ran
• Is Part Of: Organic & biomolecular chemistry. Volume 16:Issue 12(2018)
• Page Start: 2114
• Page End: 2124
• Publication Date: 2018-03-07
• Subjects: Chemistry, Organic -- Periodicals; Bioorganic chemistry -- Periodicals; Chemistry, Physical organic -- Periodicals; 547
• DOI: 10.1039/c8ob00113h
• Languages: English
• ISSNs: 1477-0520

Abstract

Abstract : The organogels were formed from fully-conjugated styrylbenzoxazoles and styrylbenzothiazoles without traditional gelation groups. Abstract : Fully-conjugated styrylbenzoxazoles and styrylbenzothiazoles ofBOAF24, BOACl24, BOACl35, BOABr24, BOABr35, BTAF24, BTACl24 andBTABr24 without traditional gelation groups could form organogels. It was found that introduction of chlorine atoms in the 2, 4-positions of the phenyl group would improve gelation abilities, and benzothiazole derivatives exhibited better gelation abilities than benzoxazoles with a similar π-skeleton due to better π-electron delocalization. Interestingly, the organogel ofBTACl24 could change into solution by UV light due to trans – cis isomerization, which could also induce morphological changes in xerogels. The smooth organogel nanofibers stretched out lots of thin 'arms' to hold together or to catch other nanofibers upon UV irradiation, so more entangled networks were generated. Moreover, TFA (trifluoroacetic acid) could induce a gel–sol transformation on account of the protonation of the benzoxazole or benzothiazole unit, accompanied by emission quenching.BTACl24 exhibited higher performance thanBOACl24 in the detection of TFA because of its strong basicity. The decay time and the detection limit ofBTACl24 in xerogel-based film towards TFA vapor were of 0.7 s and 0.3 ppm, respectively. Therefore, organogelation of non-traditional organogelators is a powerful approach to the fabrication of multi-stimuli-responsive soft materials, and provides a new method to generate more entangled 3D networks through photochemical reactions in xerogels.