exo-6b2-Methyl-Substituted Pentabenzocorannulene: Synthesis, Structural Analysis, and Properties.
Angew Chem Int Ed Engl
; : e202408321, 2024 Jun 26.
Article
em En
| MEDLINE
| ID: mdl-38926096
ABSTRACT
exo-6b2-Methyl-substituted pentabenzocorannulene (exo-PBC-Me) was synthesized by the palladium-catalyzed cyclization of 1,2,3-triaryl-1H-cyclopenta[l]phenanthrene. Its bowl-shaped geometry with an sp3 carbon atom in the backbone and a methyl group located at the convex (exo) face was verified by X-ray crystallography. According to DFT calculations, the observed conformer is energetically more favorable than the endo one by 39.9â
kcal/mol. Compared to the nitrogen-doped analogs with intact π-conjugated backbones (see the main text), exo-PBC-Me displayed a deeper bowl depth (avg. 1.93â
Å), redshifted and broader absorption (250-620â
nm) and emission (from 585 to more than 850â
nm) bands and a smaller optical HOMO-LUMO gap (2.01â
eV). exo-PBC-Me formed polar crystals where all bowl-in-bowl stacking with close π â
â
â
π contacts is arranged unidirectionally, providing the potential for applications as organic semiconductors and pyroelectric materials. This unusual structural feature, molecular packing, and properties are most likely associated with the assistance of the methyl group and the sp3 carbon atom in the backbone.
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MEDLINE
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En
Ano de publicação:
2024
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Article