Dual-State Emissions of Dihydroquinoxaline Derivatives

Abstract

The study of dual-state emissions is an emerging field of research with tremendous potential as DSEgens overcome limitations of two mutually exclusive phenomena of aggregation-caused quenching and aggregation-induced emissions. These materials have versatile applications in optoelectronic devices, bioimaging, chemical sensors, and data encryption. In this study, a new series of dual-state emissive compounds, featuring the dihydroquinoxaline framework is introduced. These derivatives were accessed via facile synthetic routes. By leveraging on specific molecular design strategies such as donorπ-acceptor moieties, partially planar aromatic core with attached phenyl/aryl rings in a twisted molecular conformation, and varying substituents, dual-state emissions were achieved in three dihydroquinoxaline derivatives. These exhibited photoluminescent quantum yields ranging from 47% to 60% in solution, and 42% to 53% in solid states. In contrast, two derivatives showed solid state fluorescence quenching. Single crystal X-ray diffraction analyses reveal key intermolecular hydrogen bonding interactions to the imine nitrogen resulting in fluorescence quenching in these derivatives in the solid state. This study presents the first addition of the dihydroquinoxaline framework to the suite of DSE luminogens.