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.

Directly investigating hydrogen bond (HB) dynamics in molecular materials is a challenging task. Here, we report a set of porphyrin isomers, porphycenes, that visualize slight changes on the order of picometers in the intramolecular HB dynamics. Intramolecular HBs of porphycenes were regulated by the systematic modification at meso positions with methyl (Me), cyclopentyl (Cy5), and cyclohexyl (Cy6) moieties. Notably, the quantum yields varied from 35 to 0.04% in chloroform, depending on a slight distortion in the porphycene framework. SC-XRD, XPS, and NMR clearly revealed that the Me and Cy6 moieties increased the nonradiative deactivation by strengthening the intramolecular NH•••N HBs whereas Cy5 retained their photoluminescence properties. This is the first example of how the distortion of planar porphyrinoids at the picometer level along with the strength of the intramolecular NH•••N HBs can drastically affect their optical properties. The results revealed new avenues of HB engineering based on porphyrinoids.

meso-Tetraalkyl porphycenes exhibit unique optical properties with wide potential applications. The very fact that incorporation of porphycenes into polymeric materials is rare, make this approach a particularly attractive one. In this work, meso-tetrakis(3-butenyl)porphycene bearing four terminal olefin groups is prepared via two synthetic strategies: 1) the McMurry reaction using 5,5′-diacyl-2,2′-bipyrroles as precursors and 2) the oxidative coupling of dipyrroethenes. The newly obtained porphycene has been characterized by single X-ray crys- [a]

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.