Semitubular Aromatic Fragment of Schwarzite P192: A Conserved Structural Motif with Two Embedded Octagons
Mingwei Wang, Jiangtao Chan, Qirui Long, Yvonne Vonhausen, Frank Würthner, Wei Jiang, Zhaohui Wang
Abstract
High Resolution Image Download MS PowerPoint Slide Molecular carbons with negative curvature constitute the foundation for the precise synthesis of schwarzite carbon. Herein, we report the successful synthesis of a distinctive semitubular molecule comprising two [8]circulene moieties, achieved through Scholl oxidation of a twisted bismacrocyclic precursor. Notably, the two octagonal motifs enforce a nearly 180° bend of the π-system. The highly warped structure of the semitube was revealed by X-ray crystallographic studies, and the flexibility of the π skeleton was illustrated by experimental and theoretical investigation. The structure exhibits an excellent match to the substructure of Schwarzite P192 confirmed by root-mean-square deviation (RMSD) analysis. Furthermore, the large negatively curved π-surface of the saddle allows interactions with multiple C 60 molecules, yielding a well-defined cocrystalline assembly. This study opens a promising avenue to the rational design and synthesis of negatively curved molecular carbon materials that combine π-conjugation with high porosity.