Difluoromethoxyl bridged substituted 2-cyano-pyrrole based pure organic luminescent liquid crystals towards white light emitting single-molecule

Luo, Shunyin; Yang, Guoliang; Zhang, Mei; Lu, Liping; Mo, Xiaofeng; Irfan, Majeed; Zhang, Zhuo

doi:10.1080/02678292.2023.2203123

Cited by 3 publications

(1 citation statement)

References 41 publications

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“…The flexible chains introduced at the end of the peripheral ring of HAB have a significant effect on the molecular aggregated structures, contributing to dramatic alterations in solid-state luminescence properties and the emergence of liquid-crystalline states [13,14], in which luminescent liquid crystals with both properties are well recognized as one of the promising functional materials [15]. As part of our research project on partially fluorinated HAB-based fluorescent molecules, we synthesized unsymmetrical partially Research concept and chemical structures of (a-c) various hexaarylbenzenes reported in our previous studies [12] and (d) partially fluorinated hexaarylbenzenes, e.g., 1b-f and 2b-f, with a various length of alkoxy chain used in this study.…”

Section: Introductionmentioning

confidence: 99%

Unsymmetrical and C3-Symmetrical Partially Fluorinated Hexaarylbenzenes: Effect of Terminal Alkoxy Chain Length on Photophysical and Thermophysical Behavior

Wang,

Yamada,

Yasui

et al. 2024

Symmetry

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Solution-state photoluminescence (PL) is affected by the electronic state; however, solid-state PL varies widely depending on the aggregated state. Although the synthesis and photophysical properties of unsymmetrical and C3-symmetrical hexaarylbenzenes (HABs) have been reported, the influence of their terminal alkoxy chains on their physical properties remains unclear. Therefore, we synthesized a series of unsymmetrical and C3-symmetrical partially fluorinated HABs with different alkoxy chains and investigated the effects of alkoxy chain length on the thermophysical and photophysical properties. While investigating phase transition behavior, the ethoxy-substituted unsymmetrical derivative revealed a columnar liquid-crystalline phase, whereas the other derivatives only exhibited a phase transition between crystalline and isotropic phases. While evaluating PL behavior, both the unsymmetrical and C3-symmetrical analogs exhibited relatively strong blue PL, independent of the alkoxy chain length. Through-space π-conjugation caused the PL spectra of C3-symmetrical derivatives to redshift compared to those of unsymmetrical derivatives. Partially fluorinated HABs exhibited relatively strong fluorescence, even in the crystalline state, depending on the alkoxy chain length, owing to the formation of various aggregated structures. Crystalline fluorinated HABs exhibited photochromism, resulting in the appearance of long-wavelength PL bands when exposed to ultraviolet (UV) irradiation, making them promising candidates for PL sensing materials for UV detection.

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