Axially-chiral boramidine for detailed (chir)optical studies

The inclusion of boron atoms into chiral pi-conjugated systems is an effective strategy to unlock unique chiroptical properties. Herein, the preparation and characterization of a configurationally stable axially-chiral boramidine are reported, showcasing absorption in the UV domain, deep-blue fluorescence (phi up to 94%), and ca. |10-3| gabs and glum values. Detailed photophysical studies and quantum-chemical calculations clearly elucidate the deactivation pathways of the emissive state to triplet excited states, involving increased spin-orbit coupling between the lowest singlet excited state and an upper triplet state. An axially-chiral boramidine displays UV-absorption, deep-blue fluorescence (phi up to 94%), and |10-3| gabs and glum. Deactivation pathways of the emissive state to triplet excited states, involving increased spin-orbit coupling, are identified.