Speaker
Description
The design of advanced luminescent materials increasingly relies on heteroatom-containing aromatic systems with finely tunable optical properties. Among these, pyrene derivatives and their isosteres, particularly azapyrenes, offer promising structural motifs for applications in organic electronics. This study presents the development of a synthetic strategy and the comprehensive characterisation of 2,7-diazapyrene and related derivatives. Target compounds were obtained, including unsubstituted 2,7-diazapyrene, non-K substituted pyrenes and non-K and K-region substituted diazapyrenes. Efficient synthetic routes were established using microwave-assisted procedures affording the desired products in satisfactory yields. The compounds were characterized by 1H and 13C NMR and FTIR spectroscopy, while their thermal behavior was investigated using TGA and DSC. Particular emphasis was placed on photophysical studies, including UV–Vis absorption and emission spectroscopy under varying solvent polarity. Experimental observations were supported by DFT and TD-DFT calculations, providing insights into molecular geometries, frontier orbital distributions, and electronic transitions. The results reveal that nitrogen incorporation into the pyrene scaffold significantly alters electronic structure and emissive properties, while substitution patterns in the non-K versus K regions modulate band gaps, dipole moments, and molecular planarity. These findings highlight diazapyrenes as a versatile platform for the development of next-generation luminescent materials.
This research was funded by the National Science Centre, Poland, under the SONATA programme, grant no. 2023/51/D/ST5/00369.
