Development of a Fluorescent Nanofibrous Template by In Situ SNAr Polymerization of Fluorine-Containing Terphenyls with Aliphatic Diols: Self-Assembly and Optical and Liquid Crystal Properties

Sara A Alqarni; Salhah D Al-Qahtani; Ahmad A Alluhaybi; Rua B Alnoman; Amerah Alsoliemy; Shams H Abdel-Hafez; Nashwa M El-Metwaly

doi:10.1021/acsomega.1c05690

Development of a Fluorescent Nanofibrous Template by In Situ S_NAr Polymerization of Fluorine-Containing Terphenyls with Aliphatic Diols: Self-Assembly and Optical and Liquid Crystal Properties

ACS Omega. 2021 Dec 8;6(50):35030-35038. doi: 10.1021/acsomega.1c05690. eCollection 2021 Dec 21.

Authors

Sara A Alqarni¹, Salhah D Al-Qahtani², Ahmad A Alluhaybi³, Rua B Alnoman⁴, Amerah Alsoliemy⁵, Shams H Abdel-Hafez⁶, Nashwa M El-Metwaly^{5

7}

Affiliations

¹ Department of Chemistry, College of Science, University of Jeddah, Jeddah 22441, Saudi Arabia.
² Department of Chemistry, College of Science, Princess Nourah bint Abdulrahman University, Riyadh 11671, Saudi Arabia.
³ Department of Chemistry, Rabigh College of Science and Arts, King Abdulaziz University, Rabigh 21911, Saudi Arabia.
⁴ Department of Chemistry, College of Science, Taibah University, P.O. Box 344, Madinah 344, Saudi Arabia.
⁵ Department of Chemistry, Faculty of Applied Science, Umm-Al-Qura University, Makkah 24230, Saudi Arabia.
⁶ Department of Chemistry, College of Science, Taif University, P.O. Box 11099, Taif 21944, Saudi Arabia.
⁷ Department of Chemistry, Faculty of Science, Mansoura University, El-Gomhoria Street, Mansoura 35516, Egypt.

Abstract

Stimulus-responsive supramolecular organogels have been broadly studied, but the assembly of a liquid crystalline organogel with a thermoreversible response remains a challenge. This could be attributed to the difficulty of designing organogelators with liquid crystalline properties. Nucleophilic aromatic substitution (S_NAr) has been utilized to produce a diversity of pentafluorobenzene-containing aromatics, which are very regioselective to para positions. Those pentafluorobenzene-functionalized aromatics have been ideal compounds for the preparation of calamitic liquid crystals. In this context, novel fluoroterphenyl-containing main-chain polyether (FTP@PE) was synthesized using in situ S_NAr polymerization as a convenient and effective synthetic strategy toward the development of fluorescent liquid crystals bearing fluoroterphenyl and ether groups. The fluoroterphenyl unit was synthesized by Cu(I)-supported decarboxylation cross-coupling of potassium pentafluorobenzoate and 1,4-diiodobenzene. The chemical structures of FTP@PE were studied with ¹H/¹³C/¹⁹F nuclear magnetic resonance and infrared spectra. The liquid crystal mesophases were determined with differential scanning calorimetry and polarizing optical microscopy. Ultraviolet-visible absorbance and emission spectral profiles showed solvatochromic activity. The nanofibrous morphologies were studied with a scanning electron microscope. The organogels of FTP@PE were developed in a number of solvents via van der Waals attraction forces of aliphatic moieties and π stacking of fluoroterphenyl groups. They demonstrated thermoreversible responsiveness.