Coumarin-based emissive hexacatenars: synthesis, 2D and 3D self-assembly and photodimerization. Issue 40 (26th September 2018)

• Record Type: Journal Article
• Authors: Xiao, Yulong; Tan, Xiaoping; Xing, Wei; Zhao, Kai; Zhang, Bei; Cheng, Xiaohong
• Is Part Of: Journal of materials chemistry. Volume 6:Issue 40(2018)
• Page Start: 10782
• Page End: 10792
• Publication Date: 2018-09-26
• Subjects: Materials -- Periodicals; Chemistry, Analytic -- Periodicals; Optical materials -- Research -- Periodicals; Electronics -- Materials -- Research -- Periodicals; 543.0284
• DOI: 10.1039/c8tc04040k
• Languages: English
• ISSNs: 2050-7526

Abstract

Abstract : Various 2D columnar LC phases and gels with abnormal morphologies as well as reversible LC–LC and gel–gel phase transitions caused by photodimerization were observed in novel unsymmetric coumarin polycatenars. Abstract : The first examples of unsymmetric coumarin polycatenar liquid crystals consisting of a coumarin central core with 1, 2, 3-triazole dendritic wings on both sides were synthesized via click reaction. Their properties were investigated using POM, DSC, XRD, SEM, IR, UV-vis spectra and photoluminescence measurements. Such polycatenars can self-assemble into different columnar liquid crystalline phases ranging from p 4 mm via p 2 mm to p 6 mm in their bulk states and into organogels with nanobelt or porous morphologies in different solvents. These polycatenars can exhibit highly fluorescent emission with large Stokes shifts (90–118 nm) in solution and as films. Most interestingly, the photodimerization in both LC and non-LC phases led to the formation of absolutely hexagonal columnar LC phases, while photodimerization in gel states led to the formation of flowerlike or 3D porous morphologies. Either columnar phases or gels with flowerlike or ordered porous morphologies were first observed in coumarin based derivatives.