Synthesis, characterization and self-assembly of new cholesteryl-substitued sym-tetrazine: Fluorescence, gelation and mesogenic properties

Fluorescent liquid crystalline organogels have been considered as proper candidates for low-energy consumption electronic displays particularly for portable flexible electronics. Herein, we synthesized novel fluorescent symmetric 3,6-bis(4-(cholesterylester)phenyl)-1,2,4,5-tetrazine (sym-Tetrazine; DCh-Tz) liquid crystalline low molecular weight organogelator (LMWO). The molecular structure of the prepared sym-Tetrazine was characterized by different spectroscopic methods, including H-1/C-13 NMR and FT-IR spectra. The new oganogelator, sym-tetrazine, was synthesized via an addition reaction of hydrazine monohydrate with 4-cyanobenzoic acid to give the corresponding dihydrotetrazine. The product of the addition reaction was subjected to an oxidation reaction to give 3,6-bis(4-carboxyphenyl)-tetrazine to interact with cholesterol affording the desired DCh-Tz. It was proved to possess fairly high gelation capability to generate nanofibers in various alcohols, such as 1,6-dihydroxyhexane, n-octanol and n-butanol. The mesogenic phases of the prepared cholesterylester s-tetrazine were studied by POM and DSC. The photophysical properties of the new fluorescent and thermoreversible low molecular weight organogelator from cholesterylester s-tetrazine were discussed. Both of UV-Vis absorption and fluorescence spectra showed a solvatochromic and solvatofluorochromic activities, respectively. The supramolecular selfassembly of the synthesized cholesterylester s-tetrazine occurred via van der Waals and pi-stack interaction forces to result in the gelation of various organic solvents. A dried xerogel of the cholesterylester stetrazine was studied by scanning electron microscopy (SEM) to show fiber-like nano-scaled scaffolds. Both of cytotoxicity and antimicrobial properties were explored to prove the use the current DCh-Tz for other potential applications, such as bioimaging and drug delivery systems. (C) 2021 Elsevier B.V. All rights reserved.

Automated summary

Fluorescent liquid crystalline organogels have been synthesized and discussed in terms of their application in low-energy consumption electronic displays. The molecular structure was characterized by various spectroscopic methods, demonstrating its good gelation capability in various organic solvents. In addition, cytotoxicity and antimicrobial properties were explored, providing data support for its potential applications in bioimaging and drug delivery systems.