SYNTHESIS AND CHARACTERIZATION OF NEW DONOR-ACCEPTOR CYANOARENE PHOTOCATALYSTS

In a study on Ni-catalyzed visible light-promoted C–N cross-coupling,[1] we found that the commercially available donor–acceptor cyanoarene photocatalyst 3DPA2FBN generated two by-products under blue light irradiation, identified by HPLC–MS as mono- and bis-cyclized products generated following the loss of one or two molecules of HF. Considering that PC photodegradation products can often retain a photochemical activity,[2] we decided to develop a synthetic protocol to prepare these 3DPA2FBN cyclization products, which were fully characterized and tested as PCs. 1D/2D NMR and XRD were exploited to fully elucidate the structures of the isolated regioisomers. The photophysical properties of 1 and 2 were determined by electrochemical and spectroscopic techniques. Their catalytic activity was finally assessed in several types of reactivity. Furthermore, a regioisomeric mono-cyclized product 3 was successfully isolated and characterized, which proved to be the effective precursor of 2.