This study reports the facile syntheses of tetra‐boron difluoride (tetra‐BF2) complexes, flag‐hinge‐like molecules that exhibit intense green‐to‐orange luminescence in solution and yellow‐to‐red emission in the solid states. Single‐crystal structure analysis and density functional theory calculations suggested a bent structure of this series of compounds. The complexes also exhibited excellent optical properties, with quantum yields reaching 100 % and a large Stokes shift. These properties were attributed to the altered bending angle of the molecule in the S1 excited state. As the rotational motion was suppressed around the 2,2′‐bipyrrole axis, atropisomers with axial chirality were formed, which are optically resolvable into (R) and (S)‐enantiomers through a chiral column. The atropisomers thus function as circularly polarized luminescent (CPL) materials, in which the color (green, green‐yellow, and yellow) can be varied by controlling the aggregation state. This rational design of multi‐BF2 complexes can potentially realize novel photofunctional materials.

The design and synthesis of novel circularly polarized luminescence (CPL) molecular emitters exhibiting photophysical modulation and high CPL efficiency have become an attractive research topic in synthetic and material chemistry....

This study reports the facile syntheses of tetra‐boron difluoride (tetra‐BF2) complexes, flag‐hinge‐like molecules that exhibit intense green‐to‐orange luminescence in solution and yellow‐to‐red emission in the solid states. Single‐crystal structure analysis and density functional theory calculations suggested a bent structure of this series of compounds. The complexes also exhibited excellent optical properties, with quantum yields reaching 100 % and a large Stokes shift. These properties were attributed to the altered bending angle of the molecule in the S1 excited state. As the rotational motion was suppressed around the 2,2′‐bipyrrole axis, atropisomers with axial chirality were formed, which are optically resolvable into (R) and (S)‐enantiomers through a chiral column. The atropisomers thus function as circularly polarized luminescent (CPL) materials, in which the color (green, green‐yellow, and yellow) can be varied by controlling the aggregation state. This rational design of multi‐BF2 complexes can potentially realize novel photofunctional materials.

Advancing the construction of circularly polarized luminescence (CPL) materials by molecular design has become an important target in this research area. In their Research Article (e202204358), Yoshio Hisaeda, Toshikazu Ono, and co‐workers demonstrate a new bipyrrole‐based boron difluoride family exhibiting intense multicolor luminescence with easy synthetic access. Tuning the rotational barrier around the 2,2′‐bipyrrole affords CPL, and multicolor CPL can be achieved by controlling the aggregation state.

Die Entwicklung von Materialien mit zirkular polarisierter Lumineszenz (CPL) durch molekulares Design ist ein wichtiges Forschungsziel. In ihrem Forschungsartikel (e202204358) berichten Yoshio Hisaeda, Toshikazu Ono und Mitarbeiter über neue Bordifluoride auf Bipyrrol‐Basis mit intensiver mehrfarbiger Lumineszenz. Die gezielte Abstimmung der Rotationsbarriere um das 2,2′‐Bipyrrol führte zu einem CPL‐Material, und über die Kontrolle des Aggregatzustands ließ sich eine mehrfarbige CPL herstellen.