2,4,7‐Triaminofluorenone as a Multi‐Analyte Colorimetric Sensor of Fluoride, Acetone Vapor, and Other Harmful Compounds

Abstract

Abstract2,4,7‐Triaminofluorenone, a fluorenone derived multi‐analyte colorimetric chemosensor, has been synthesized via an extremely cost‐effective synthetic pathway. The sensor molecule can detect various analytes such as fluoride ion, acetone vapor, and picric acid. The violet solution of the sensor molecule becomes deep blue in the presence of fluoride ion. It can detect fluoride down to 120 ppb level. The compound in the solid state shows vapochromism only in the presence of acetone. The grey colored solid coating of the sensor molecule becomes blue in the presence of acetone vapor. This property was utilized to sense acetone vapor. Color Grab, an android based app, was utilized to detect acetone in real time down to 10 ppm level. Apart from that, the same sensor molecule was also tested for sensing different electron deficient nitro aromatic compounds due to its electron rich framework. The sensor was found to detect picric acid selectively. The sensor compound also shows acid‐base induced color change. The violet solution of the sensor molecule becomes brown in the presence of carboxylic as well as mineral acid. This reaction is reversible. Hence, the brown solution becomes violet again in the presence of aliphatic amines as well as ammonia. Utilizing this property, a method has been described to detect two widely used highly volatile chemicals HCl and NH3 in different industries.