A modular approach to polycyclic N-fused heteroaromatics is described. Acid-catalyzed reactions of various 1-(2-oxo-2-arylethyl)-1H-pyrrole-2-carbaldehydes with several o-phenylenediamines provided facile access to a number of new benzo[d]imidazole-pyrrolo[1,2-a]pyrazine hybrid structures through double cyclodehydration and aromatization. Optical characterization of the synthesized compounds revealed unique emission properties, with deep blue emission in the aggregated and solid states, and a dramatic substituent effect was observed. Fusion of an additional benzene ring into the benzo[4,5]imidazo[1,2-a]pyrrolo[2,1-c]pyrazine scaffold resulted in a remarkable increase in the intensity of blue fluorescence from the solution along with good cell permeability and negligible phototoxicity, indicating the potential for bioimaging applications.
Bibliographical noteFunding Information:
This work was supported by the National Research Foundation of Korea (NRF) grant funded by the Korea government (MSIP) (NRF-2017R1A2A2A05069364 and NRF-2018R1A6A1A03023718) to I. K. and the National Research Foundation of Korea (NRF) grants funded by the Korean government (MSIP) (NRF-2018R1A2B2005535 and 2018R1A4A1021703) to J. L. We acknowledge Ounyoung Lim for contribution in Operetta High-Content imaging data.
© 2020 The Royal Society of Chemistry.
All Science Journal Classification (ASJC) codes
- Chemical Engineering(all)