title: A large dipole moment to promote gelation for 4-nitrophenylacrylonitrile derivatives with gelation-induced emission enhancement properties.
abstract: A series of 4-nitrophenylacrylonitrile and phenylacrylonitrile derivatives consisting of a carbazole moiety was synthesized. Some of these derivatives with longer alkyl chains and a nitro group could gelatinize some organic solvents, such as ethanol, n-butanol, ethyl acetate, and DMSO. By contrast, phenylacrylonitrile derivatives did not form gels in measured solvents. This result proved that the electron-withdrawing nitro moiety was important for gel formation because it conferred the molecules with large dipole moments, which enhanced the intermolecular interaction. Analyses by UV-vis absorption, X-ray diffraction, and scanning electron microscopy showed that the gelator molecules could self-assemble into one-dimensional nanofibers with layer packing, which further twisted into thicker fibers and formed three-dimensional networks in the gel phase. The single crystal structure of C4CNPA implied that the gelators might adopt an anti-parallel molecular stacking because of their larger ground-state dipole moment. Interestingly, the organogels had enhanced fluorescence relative to solutions at the same concentrations.
authors.affiliation: State Key Laboratory of Supramolecular Structure and Materials, College of Chemistry, Jilin University, Changchun, P. R. China. xuepengchong@jlu.edu.cn luran@mail.jlu.edu.cn.
authors.forename: Pengchong
authors.initials: P
authors.lastname: Xue
authors.forename: Boqi
authors.initials: B
authors.lastname: Yao
authors.forename: Yuan
authors.initials: Y
authors.lastname: Zhang
authors.forename: Peng
authors.initials: P
authors.lastname: Chen
authors.forename: Kechang
authors.initials: K
authors.lastname: Li
authors.forename: Baijun
authors.initials: B
authors.lastname: Liu
authors.forename: Ran
authors.initials: R
authors.lastname: Lu