A Highly Warped Heptagon‐Containing sp2 Carbon Scaffold via Vinylnaphthyl π‐Extension

A new strategy is demonstrated for the synthesis of warped, negatively curved, all‐sp²‐carbon π‐scaffolds. Multifold C?C coupling reactions are used to transform a polyaromatic borinic acid into a saddle‐shaped polyaromatic hydrocarbon ( 2 ) bearing two heptagonal rings. Notably, this Schwarzite substructure is synthesized in only two steps from an unfunctionalized alkene. A highly warped structure of 2 was revealed by X‐ray crystallographic studies and pronounced flexibility of this π‐scaffold was ascertained by experimental and computational studies. Compound 2 exhibits excellent solubility, visible range absorption and fluorescence, and readily undergoes two reversible one‐electron oxidations at mild potentials.     

A Hydrogen‐Bonded Hexagonal Buckybowl Framework

A hydrogen‐bonded two‐dimensionally networked buckybowl architecture is presented. Two types of hexagonal network (HexNet) structures ( CPSM‐1 and CPSM‐2 ) have been achieved based on a sumanene derivative ( CPSM ) possessing 4,4′‐dicarboxy‐o ‐terphenyl groups in the periphery. CPSM‐1 has a waved HexNet structure with an alternate alignment of upward and downward bowls. CPSM‐2 has a bilayered HexNet structure composed of hamburger‐shaped dimers of the bowls. This demonstrates that non‐planar π‐systems can be networked two‐dimensionally by an appropriate supramolecular synthon to achieve structurally well‐defined unique bumpy π‐sheets. Furthermore, we revealed that CPSM‐2 undergoes anisotropic shrinking along the c axis by 11 % under high pressure conditions (970 MPa). The shrinkage is brought about by offset sliding between bumpy π‐surfaces of the bilayered HexNet sheets.     

Cyclic Alkyne Approach to Heteroatom‐Containing Polycyclic Aromatic Hydrocarbon Scaffolds

We report a modular synthetic strategy for accessing heteroatom‐containing polycyclic aromatic hydrocarbons (PAHs). Our approach relies on the controlled generation of transient heterocyclic alkynes and arynes. The strained intermediates undergo in situ trapping with readily accessible oxadiazinones. Four sequential pericyclic reactions occur, namely two Diels–Alder/retro‐Diels–Alder sequences, which can be performed in a stepwise or one‐pot fashion to assemble four new carbon–carbon (C?C) bonds. These studies underscore how the use of heterocyclic strained intermediates can be harnessed for the preparation of new organic materials.     

Synthesis of Rationally Halogenated Buckybowls by Chemoselective Aromatic C−F Bond Activation

Halogenated buckybowls or bowl‐shaped polycyclic aromatic hydrocarbons (BS‐PAHs) are key building blocks for the “bottom‐up” synthesis of various carbon‐based nanomaterials with outstanding potential in different fields of technology. The current state of the art provides quite a limited number of synthetic pathways to BS‐PAHs; moreover, none of these approaches show high selectivity and tolerance of functional groups. Herein we demonstrate an effective route to BS‐PAHs that includes directed intramolecular aryl–aryl coupling through C−F bond activation. The coupling conditions were found to be completely tolerant toward aromatic C−Br and C−Cl bonds, thus allowing the facile synthesis of rationally halogenated buckybowls with an unprecedented level of selectivity. This finding opens the way to functionalized BS‐PAH systems that cannot be obtained by alternative methods.     

Synthesis of Pyrrole‐Fused Corannulenes: 1,3‐Dipolar Cycloaddition of Azomethine Ylides to Corannulene

In the long history of corannulene chemistry, the 1,3‐dipolar cycloaddition to corannulene is unprecedented. Reported herein is the 1,3‐dipolar cycloaddition of a polycyclic aromatic azomethine ylide to corannulene, a reaction which occurs exclusively at the rim bond of corannulene, from the convex side in an exo fashion. The cycloadducts were successfully converted, by successive oxidative dehydrogenation, into pyrrole‐fused corannulenes, which exhibited pronounced solvatofluorochromism.     

Synthesis of Nitrogen‐Containing Rubicene and Tetrabenzopentacene Derivatives

Carbon‐based materials, such as acenes, fullerenes, and graphene nanoribbons, are viewed as the potential successors to silicon in the next generation of electronics. Although a number of methodologies provide access to these materials’ all‐carbon variants, relatively fewer strategies readily furnish their nitrogen‐doped analogues. Herein, we report the rational design, preparation, and characterization of nitrogen‐containing rubicenes and tetrabenzopentacenes, which can be viewed either as acene derivatives or as molecular fragments of fullerenes and graphene nanoribbons. The reported findings may prove valuable for the development of electron transporting organic semiconductors and for the eventual construction of larger carbonaceous systems.     

Redox‐Active Corannulene Buckybowls in a Crystalline Hybrid Scaffold

A porous crystalline corannulene‐containing scaffold, which combines the periodicity, dimensionality, and structural modularity of hybrid frameworks with the intrinsic properties of redox‐active π‐bowls, has been prepared. Single‐crystal and powder X‐ray diffraction, ab initio density functional theory computations, gas sorption analysis, fluorescence spectroscopy, and cyclic voltammetry were employed to study the properties of the novel corannulene derivatives and the buckybowl‐based hybrid materials. X‐ray diffraction studies revealed the preservation of the corannulene bowl inside the prepared rigid matrix, which offers the unique opportunity to extend the scaffold dimensionality through the buckybowl curvature. Merging the inherent properties of hybrid frameworks with the intrinsic properties of π‐bowls opens a new avenue for preparing redox‐active materials and potentially improving charge transport in the scaffold.     

Synthesis of a Configurationally Stable Three‐Legged Piano‐Stool Complex

A transition metal Lewis acid with metal‐centered chirality is obtained by η⁶:η¹:η¹ coordination of a 1,3‐disubstituted arene with a phosphane and a pyrazole tether (PArN) to ruthenium. The three‐legged piano‐stool complex [{η⁶:η¹:η¹‐(PArN)}Ru(H₂O)]²⁺ (structure depicted) displays remarkable configurational stability. Its planar chiral, neutral precursor [{η⁶:η¹‐(PArN)}RuCl₂] can be resolved by preparative HPLC.