Amplifying Emission Enhancement and Proton Response in a Two-Component Gel

Abstract

A glutamide gelator, 1, was synthesized, and a weak emission enhancement was observed during its gelation. In addition, 1 could be an excellent scaffold for successfully embedding an energy acceptor, 2, into its aggregate to obtain highly efficient energy transfer. An amplification of the emission enhancement was observed in the two-component gels compared to that of the neat gel of 1 during gel formation. For example, 1 induced only a 2.5-fold increase in emission intensity, whereas a 23-fold enhanced emission could be observed in the two-component gel with only 1.6 mol % 2. Furthermore, two-component gels had an excited proton response. In systems with low acceptor concentrations, the hot solution red-shifted the fluorescence from blue to yellow upon the addition of a proton, which continuously blue-shifted with decreasing temperature to form the gel given that the binding of the gelator to the proton is weakened during coassembly. Moreover, the casting film formed by the two-component wet gel had an excellent response to volatile acids such as hydrochloric acid, trifluoroacetic acid, and so on and could be reversibly recovered by exposure to NH(3).

pH sensitive smart gels of cetylpyridinium chloride in binary solvent mixtures: phase behaviour, structure and composition

“…25 Recently, crown ether based bolaamphiphilic low-molecular weight gelator which could form gels both in organic and aqueous media was reported by Zheng et al 26 Recent developments have also employed various triggers which include solvent composition, 27 magnetic elds, addition of salts 28 and photoresponsive UV light. 34 Stimuli-responsive gels have received increased attention where the guest molecules can be entrapped or released by stimulating external factors such as pH or temperature, responsible for the supramolecular network. 32 Bhuniya and Kim 33 synthesized novel and highly efficient uorescent hydrogelators that showed the ability to sense biological entities, such as, glucose and insulin at very low concentrations.…”

Luminescent Nanofibers Fabricated from Phenanthroimidazole Derivatives by Organogelation: Fluorescence Response towards Acid with High Performance

“…Although acid‐mediated gel–sol transition has been studied in LMOG, the sensing properties of the luminescent nanofibers fabricated from π‐gelators to detect acid vapors were seldom reported . We have found that the xerogel‐based film formed from cyanostilbene derivatives with an imidazole unit exhibited a rapid fluorescence response towards acid vapors . Therefore, we reasoned that phenanthroimidazole derivatives bearing an extended π‐conjugated unit of fused imidazole could also sense acids.…”

“…[10] We have found that the xerogel-based film formed from cyanostilbene derivatives with an imidazole unit exhibited ar apid fluorescencer esponse towards acid vapors. [11] Therefore, we reasoned that phenanthroimidazole derivatives bearing an extended p-conjugated unit of fused imidazole could also sense acids. To the best of our knowledge,a no rganogelator based on ap henanthroimidazole derivativeh as not been reported.…”

Halogen Atom and Position Dependent Strong Enhancement of Solid‐State Fluorescence and Stimuli Responsive Reversible Fluorescence Switching

“…Organic solid state fluorescent materials have received strong interest over few decades because of their potential applications ranging from materials technology to biological science . In particular, switchable and tunable solid state fluorescent materials are highly desirable for optical switches, data recording, sensors, displays and security devices .…”