Photophysical Properties of an Azine-Linked Pyrene-Cinnamaldehyde Hybrid: Evidence of Solvent-Dependent Charge-Transfer-Coupled Excimer Emission

Abstract

We report the photophysical properties of a synthetic asymmetric azine-based compound (17Z,18E)-4′-((E)-3-phenylallylidene)-1′-(dimethylamino)-1-((pyren-8-yl)methylene)hydrazine (PYNC). The molecule PYNC shows an appreciable red shift in the emission maximum in a wide range of solvents. In water, PYNC shows the characteristic feature of excimer formation exclusively. However, in all other solvents, the excimer band is present alongside the charge transfer emission band. The assignment of charge transfer and excimer bands has been established by various steady-state emission spectral data. PYNC, owing to this novel excimer-coupled charge transfer phenomenon, can be a potential probe for studying various supramolecular assemblies of biological interest.