153237-51-5Relevant articles and documents
Exceptional dual fluorescent, excited-state intramolecular proton-transfer (ESIPT) columnar liquid crystals characterized by J-stacking and large Stokes shifts
Kanakala, Madhu Babu,Yelamaggad, Channabasaveshwar V.
, (2021/03/19)
Excited-State Intramolecular Proton-Transfer (ESIPT) fluorophores are emerging as promising future materials for electronic and biotechnological applications. ESIPT columnar (Col) liquid crystals (LCs) have been especially projected as the apt materials for advanced technological endeavors. But, there are hardly any explorations in this direction and thus, needing immediate attention. Herein we report on the synthesis, characterization, and ESIPT activity of a homologous series of novel phasmidic bis(N-salicylideneaniline) Col LCs. Optical microscopic, calorimetric and powder X-ray diffraction (XRD) studies evidence the occurrence of hexagonal columnar (Colh) phase having p6mm symmetry where the constituent slices result from the self-assembly of a pair of mesogens in a side-by-side manner facilitated by intense longitudinal π-π interactions. X-ray data confirm the absence of both directionally correlated tilting of the slices and transverse core-core interactions within the columns. Fluorescence probing clearly evidence the ESIPT occurring not only in DCM solution of the mesogens but also in their three-condensed states viz., solid, liquid crystal, and isotropic liquid phase; in general, two archetypal emission bands at ~430 nm (weak) and ~ 630 nm (strong) with large Stokes shifts (250–275 nm) of ESIPT phenomenon have been observed. The slow shift of emission maxima of the ESIPT fluorescence as a function of decreasing temperature without photoluminescence quenching coupled with the estimated tilt angle (?) of the slices normal to the columnar axis (37 to 42o), from the XRD data, confirm the formation of so-called Scheibe or J-aggregates. The redox activity, metal ion sensing ability, and solvatochromism of the mesogens have also been investigated. The study suggests that these ESIPT Col LCs with band-gap of about 3 eV can be regarded as wide-bandgap semiconducting materials having the electronic characteristics falling between those of conventional semiconductors and insulators.
Synthesis of triphenylene discotic liquid crystals possessing nine alkyl chains: Influence of molecular symmetry and chain length on mesomorphism
Xiao, Bo,Liu, Zhao-Jun,Wang, Bi-Qin,Hu, Ping,Redshaw, Carl,Zhao, Ke-Qing
, p. 25 - 35 (2013/08/23)
A series of new triphenylene discotic liquid crystals has been synthesized by a straightway and the influence of molecular symmetry and chain length on the mesomorphism investigated. The symmetrical compounds 1, 3,7,11- trimethoxytriphenylene-2,6,10-triyl tris(3,4,5-tris(alkyloxy)benzoate), with alkyl chain lengths of C7, C8, C10, and C12, and the unsymmetrical compounds 2 were studied by using polarized optical microscopy (POM), differential scanning calorimetry (DSC) and by wide-angle X-ray diffraction (XRD). The results showed that the symmetrical compounds 1a (C7) and 1b (C8) exhibit a plastic columnar mesophase, whereas the other compounds display a hexagonal columnar mesophase over a wide temperature range. All symmetrical compounds 1 display higher isotropization temperatures than that of the unsymmetrical 2. The clearing points are lowered as the alkyl chain lengthened.
LIQUID PORPHYRIN DERIVATIVE AND METHOD FOR PRODUCING THE SAME
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Page/Page column 12, (2010/12/17)
The present invention is to provide a liquid porphyrin derivative at 25 °C and at temperatures from 26 to 40 °C, and a method for producing the same. The liquid porphyrin derivative of the present invention is represented by the following formula (1): whe
