One-Step Access to New Polycyclic Aromatic Hydrocarbons via Pd-Catalysed CH Bond Functionalization

The cycloheptene and cycloheptatriene coupling with polycyclic aromatic hydrocarbons proved to be promising as it allowed isolating new compounds, which is scientifically significant in terms of its potential application in various chemical fields. These compounds were synthesized relying on a new methodology where some principles of green chemistry were adopted. Thus, the reaction occurring in one step via a C–H bond functionalization was catalyzed by a small amount of palladium acetate associated with potassium acetate as an inexpensive base under ultrasonic activation in two-phase medium using water (green solvent) in the presence of an organic solvent, where significant yields were obtained remarkably without using any additive. In addition, we managed to reduce the reaction time from 16 h during thermal activation to 7–10 min under ultrasonic irradiation to isolate six novel fluorescent semiconductor compounds whose CIE chromaticity coordinates displayed different colors.