Triphenylamine derivative-based supramolecular self-assembly system for selective sensing methanol via hydrogen bonding

Abstract

A novel gelator (TAPA) based on a triphenylamine derivative containing three pyridine groups was designed and synthesized, which could self-assemble into a gel in toluene and o-dichlorobenzene with their corresponding critical gel concentration of 25.0 and 3.12 mg mL−1. Yellow light emitting gel could be obtained, and generated clusters in the micron size range and nanofiber structures. The self-assembly process of TAPA in toluene and o-dichlorobenzene was studied by multiple technologies. Interesting, solutions TAPA in different solvents exhibited different emission behavior. Especially, the emission behavior was prohibited in alcohol solution and the emission quenching performance was enhanced with the alkyl chain of alcohol shortening. In view of this peculiarity, compound TAPA could detect methanol in solution and xerogel state. The limit of detection (LOD) of solution TAPA and xerogel TAPA towards methanol was low as 2.58 mg L1 and 26.68 ppb. NMR experiments and theoretical calculations revealed that the possible detection mechanism was the molecule structure transformation from the enol form to amide structure of TAPA under the inducing of methanol by intermolecular hydrogen bonding.