Synthesis, Optical, and Mesomorphic Properties of Self-Assembled Organogels Featuring Phenylethynyl Framework with Elaborated Long-Chain Pyridine-2,6-Dicarboxamides

Abstract

A series of new organogelators with pi-conjugated phenylethynyl framework featuring long-chain carboxamides have been synthesized. These organgelators have shown great ability to gel a variety of organic solvents to form stable organogels with the minimum gelation concentration as low as 0.1 wt %. Gelation is completely thermoreversible, and it occurs due to the aggregation of the organogelators resulting in the formation of a fibrous network via a combination of intermolecular hydrogen bonding, pi-pi stacking, and van der Waals interactions that is observed for the xerogels by TEM. The influence of sol-to-gel transition has been explored in detail by variable-temperature 1H NMR, UV-vis absorption, and fluorescence spectroscopy. Aggregation-induced enhanced emission has been observed in these organogelator molecules with an order of higher fluorescence quantum yields from solution to gels. In addition, some molecules also exhibit unique liquid crystalline properties over a large temperature range as revealed by DSC and POM studies.

Transcription of Chirality in the Organogel Systems Dictates the Enantiodifferentiating Photodimerization of Substituted Anthracene

“…The origin of the unique wide‐angle diffraction peak for the G ‐Hx system for a distance approximately 3.2 Å can be attributed to the intracolumnar spacing between two stacked molecular planes. This distance is a little shorter than that of typical π‐stacked systems 15c,f. 16d However, in a very tightly packed gelator arrangement, the stacking distance can be shortened.…”

“…In the sol state that usually occurs at elevated temperatures, the molecularly free species of the gelator is conformationally flexible, which typically allows the faster and more efficient nonradiative decay from the excited state. Formation of the gel upon molecular association reduces the conformational flexibility and consequently slows down the nonradiative decay process, thereby resulting in enhanced emission 15f. However, the above interpretation may be applicable to all systems except G ‐Hx.…”

High‐Performance Dipolar Organic Dyes with an Electron‐Deficient Diphenylquinoxaline Moiety in the π‐Conjugation Framework for Dye‐Sensitized Solar Cells

“…Analytical instruments and measurements: Absorption and emission spectra were recorded according to previously published procedures. [68] Cyclic voltammetry experiments were carried out at room temperature with a conventional three-electrode configuration consisting of a platinum working electrode, a platinum wire auxiliary electrode, and a non-A C H T U N G T R E N N U N G aqueous Ag/AgNO 3 reference electrode. [69] The potentials were quoted against the ferrocene/ferrocenium internal standard and converted to NHE by addition of 0.63 V. The solvent contained 1.0 mm of the dye and 0.1 m tetrabutylammonium hexafluorophosphate as the supporting electrolyte in all experiments.…”

“…Analytical instruments and measurements : Absorption and emission spectra were recorded according to previously published procedures 68. Cyclic voltammetry experiments were carried out at room temperature with a conventional three‐electrode configuration consisting of a platinum working electrode, a platinum wire auxiliary electrode, and a nonaqueous Ag/AgNO 3 reference electrode 69.…”

Synthesis, mesomorphic and gelation properties of 7-alkoxycoumarin-3-carbonyl hydrazine

“…In recent years, there has been growing interest in the rational design and synthesis of some new organic molecules that can exhibit thermotropic mesomorphic behaviours (liquid crystals, LCs) and gelate with kinds of solvents (low-molecular-mass organic gelators, LMOGs) [1][2][3][4][5][6]. Both LCs and LMOGs are organised soft materials, where hydrogen bonding, π-π stacking, van der Waals interaction, coordination interaction and other weak interactions are considered as the general driving force of the mesophase and gel formation.…”