Abstract
A pyridine-fused triazapentalene shows weak fluorescence in solution and is readily accessible via nitrene-mediated cyclization. In this study, a modified Cadogan reaction was used to synthesize HetATAP 1. Palladium-catalyzed reactions have been used as post-functionalization methods. Interestingly, modified Suzuki cross-couplings with various boronic acids resulted in poor to moderate yields of HetATAPs 2-5 which were arylated at the azole moiety. Direct CH arylation of HetATAP 1 gave the products with the same regiochemistry in satisfactory yields. The structures of HetATAPs 2-5 were confirmed using NMR analysis. In addition, the photophysical properties of HetATAPs 1-5 were studied under various conditions. Particularly, the emission of HetATAPs 2-5 is enhanced in the solid and aggregate state.