α-Cyanostyrenes with Pyrene Scaffold: Unique Emission through Aggregation

α-cyanostyrenes bearing a pyrene scaffold are synthesized and characterized using spectroscopic techniques. The pyrenyl styrenes are weakly emissive in solution state but show enhanced emission in water due to the formation of aggregates. The restrictions of intramolecular rotations, increased π-π interactions contribute to the strong emission of the dye molecules in the aggregated state. The formation of the aggregates, its size and morphological changes was investigated by using scanning electron microscopy (SEM) and dynamic light scattering (DLS) studies. Time-dependent density-functional theory (TDDFT) studies were also carried out and the results correlate with the experimental observations.