Narrowband Blue Circularly Polarized Luminescence Emitter Based on BN‐Doped Benzo[6]helicene with Stimuli‐Responsive Properties

Abstract

AbstractBoron‐doped helicenes, known for their unique electronic and photophysical properties, are of great interest for numerous applications. This research introduces two new azabora[6]helicenes, H[6]BN1 and H[6]BN2, synthesized through an efficient method. These molecules have boron and nitrogen atoms in opposing positions, enhancing their distinctive attributes. Both helicenes show excellent emission properties, with H[6]BN1 and H[6]BN2 exhibiting narrowband blue fluorescence and circularly polarized luminescence (CPL), achieving glum values of 4~5×10−4 which is beneficial for chiroptical applications. The addition of a donor group, 3, 6‐di‐tert‐butyl‐9H‐carbazole, in H[6]BN2 improves luminescence, likely due to enhanced molecular orbital overlap and electron delocalization. H[6]BN1′s needle‐like single crystals exhibit mechanochromism, changing luminescent color from yellow to green under mechanical stress, which is promising for stimulus‐responsive materials. In conclusion, this study presents a novel class of BN[6]helicenes with superior chiroptical properties. Their combination of electronic features and mechanochromism makes them ideal for advanced chiroptical materials, expanding the potential of helicene‐based compounds and offering new directions for the synthesis of molecules with specific chiroptical characteristics.