Premium
A Metallogel Based on a Zwitterionic Spirocyclic Meisenheimer Complex: Sensing of Fluoride Ions in Water and Moisture Content in Organic Solvents
Author(s) -
Mohar Mrittika
Publication year - 2019
Publication title -
chemistryselect
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.437
H-Index - 34
ISSN - 2365-6549
DOI - 10.1002/slct.201900939
Subject(s) - fluoride , dichloromethane , chemistry , aqueous solution , chloroform , picric acid , fluorescence , solvent , detection limit , ion , water content , inorganic chemistry , photochemistry , organic chemistry , chromatography , physics , geotechnical engineering , quantum mechanics , engineering
Design and synthesis of stimuli‐responsive materials are highly desired for various practical applications. For this purpose, a picric acid and N,N′‐dicyclohexylcarbodiimide based highly rigid zwitterionic spirocyclic Meisenheimer complex has been applied to produce a metallogel. The Meisenheimer complex does not undergo self‐gelation under any condition. But it forms a stable gel only with Fe 3+ ion in a 2:1 ratio in chloroform. Interestingly, the Meisenheimer complex shows bright yellow emission under 366 nm UV light. But the Fe 3+ based metallogel does not show any emission under UV irradiation. However, in the presence of fluoride contaminated water, the metallogel surface shows bright yellow emission while checking inside a UV chamber. Thus the non‐fluorescent metallogel was utilized as a sensor of aqueous fluoride ion. The sensor is able to detect aqueous fluoride down to 156 ppb concentration. Like the gel, the dried metallogel solution is also non‐fluorescent in different polar as well as nonpolar organic solvent. But the same solution shows bright yellow emission in the presence of water. The fluorescence intensity was found to increase with an increase in the percentage of water. In this way, the xerogel was utilized as a sensor of undesired water content present in different organic solvents which can detect moisture content with a minimum detection limit of 0.04% for dichloromethane.