Self-assembly and luminescence of pyrazole supergelators

Abstract

Functional supramolecular organogelators containing a luminescent 4-arylpyrazole unit are described. Moreover, the compounds show supergelator behaviour. The synthesised molecules combine a 1H-pyrazole ring, an amide group and a trialkoxyphenyl group. The study of the gelation process and the structure–property relationship reveals that both the pyrazole and the amide groups are essential for the H-bonding driven gelation process. Chiral derivatives with a similar chemical structure are able to amplify molecular chirality through the formation of aggregates and gel fibers with supramolecular chirality by a cooperative self-assembly mechanism which follows a nucleation–elongation model. The compounds are luminescent in solution and they are able to enhance this property in the gel, exhibiting a remarkable aggregation-induced enhancement of emission (AIEE effect). Therefore, these novel molecules are able to efficiently amplify properties such as chirality and luminescence from the molecular level to the macroscopic level.