Construction of Heptagon‐Containing Molecular Nanocarbons

Abstract

Molecular nanocarbons containing heptagonal rings have attracted increasing interest due to their dynamic behavior, electronic properties, aromaticity, and solid‐state packing. Heptagon incorporation can not only induce negative curvature within nanocarbon scaffolds, but also confer significantly altered properties through interaction with adjacent non‐hexagonal rings. Despite the disclosure of several beautiful examples in recent years, synthetic strategies toward heptagon‐embedded molecular nanocarbons remain relatively limited due to the intrinsic challenges of heptagon formation and incorporation into polyarene frameworks. In this Review, recent advances in solution‐mediated and surface‐assisted synthesis of heptagon‐containing molecular nanocarbons, as well as the intriguing properties of these frameworks, will be discussed.

Bowl‐Shaped Pentagon‐ and Heptagon‐Embedded Nanographene Containing a Central Pyrrolo[3,2‐b]pyrrole Core

“…The smallest curved subunits of C 60 , corannulene, [8–12] and sumanene, [13, 14] have been exhaustively investigated and serve as scaffolds for the syntheses of diverse, topologically unique molecular nanocarbons [15–19] . On top of the pursuit of well‐defined carbon‐rich materials, [20–23] multifaceted research on bowl‐shaped nanographenes contributes to fundamental science, addressing questions regarding the nature of aromaticity, [24–26] strain energies, [27, 28] and metal complexation [29] . Inducing a curvature in π‐extended systems, usually requires harsh conditions which rarely tolerate electron‐rich heterocycles.…”

Visualizing electron delocalization in contorted polycyclic aromatic hydrocarbons

“…With progress of organic synthesis this paradigm has gradually shifted, and a variety of non-planar PAHs, possibly chiral and/or embedding odd-membered rings, are now available. [17][18][19][20][21][22][23][24] Contrary to what is occurring in their planar counterparts, the determination of  and  orbital blocks in nonplanar molecules and the analysis of their magnetic properties is a challenge, especially for the assessment of their local and global aromatic character. To do so, computational methods based on magnetic criteria have emerged as reliable tools and constitute the stateof-the-art approaches.…”

Scholl reaction as a powerful tool for the synthesis of nanographenes: a systematic review

“…The reaction pathway consisted of many intermediate states but the fundamental step, where the nal product combining the azulene motifs was formed, occurred on the Au(111) surface. 134 Overall, it is concluded that AuCl 3 proves to be a better oxidant due to its excellent oxidizing capacity as compared to all the abovementioned oxidants. Its reduction potential value is +1.50 V.…”