Synthesis, Properties, and Packing Structures of Corannulene‐Based π‐Systems Containing Heptagons

Abstract

Introduction of heptagons into hexagonal carbon lattices can generate negatively curved polycyclic aromatic hydrocarbons, which are of significant interest in the field of exotic molecular nanocarbons. We have successfully synthesized and characterized corannulene-based π-systems containing heptagons (4 and 5) as new negatively curved polycyclic aromatic hydrocarbons as well as possible intermediates in the synthesis of warped nanographene 1. The formation of 4 and 5 represents the first example for which a heptagon is formed under Scholl reaction conditions before all hexagons are formed. Even more interestingly, we discovered that the mode and degree of solid-phase intermolecular π-π interaction can be altered significantly by the degree of ring closure.

Synthetic Applications of Oxidative Aromatic Coupling—From Biphenols to Nanographenes

“…An oxidative closure of five seven‐membered rings around a corannulene core yields the large asymmetric saddle‐shaped PAHs 196 a – c , as reported by Itami, Scott, and co‐workers (Figure ) . The authors demonstrated two different oxidative coupling strategies to construct the curved skeleton of these compounds.…”

“…The authors demonstrated two different oxidative coupling strategies to construct the curved skeleton of these compounds. Oxidation of deca(4‐ tert ‐butylphenyl)corannulene with FeCl 3 afforded the product 196 a in 62 % yield, whereas penta(biphenyl)‐substituted corannulenes yielded the corresponding curved PAHs 196 b and 196 c upon treatment with DDQ/TfOH (40 and 50 % yield, respectively) . The ease of closure of the seven‐membered rings is noteworthy, since an analogous reaction failed for the model compound [6]helicene .…”

“…[211] An oxidative closure of five seven-membered rings around ac orannulene core yields the large asymmetric saddle-shaped PA Hs 196 a-c,a sr eported by Itami, Scott, and co-workers ( Figure 15). [212][213][214] Theauthors demonstrated two different oxidative coupling strategies to construct the curved skeleton of these compounds.O xidation of deca(4tert-butylphenyl)corannulene with FeCl 3 afforded the product 196 a in 62 %y ield, [212] whereas penta(biphenyl)-substituted corannulenes yielded the corresponding curved PA Hs 196 b and 196 c upon treatment with DDQ/TfOH (40 and 50 % yield, respectively). [212][213][214] Thee ase of closure of the sevenmembered rings is noteworthy,s ince an analogous reaction failed for the model compound [6]helicene.…”

Versatile synthesis and enlargement of functionalized distorted heptagon-containing nanographenes

“…9 The X-ray crystal structure confirmed the distortion caused by the odd-membered rings, drastically enhancing solubility in organic solvents. Comparison with a purely hexagonal nanographene shows that the distortion of the planar sheet affects its electronic and optical properties.…”

A Water‐Soluble Warped Nanographene: Synthesis and Applications for Photoinduced Cell Death

“…[1,[14][15][16][17][18][19][20][21][22][23] Due to their saddle-shaped skeletons,n egatively curved nanographenes exhibit relatively weak inter- molecular p-p interactions and good solubility in organic solvents;t hey also possess interesting nonlinear optical and electrochemical properties.R ecently,w er eported aw arped nanographene (WNG) with one five-membered ring and five seven-membered rings in the hexagonal lattice ( Figure 1b). [1,[14][15][16][17][18][19][20][21][22][23] Due to their saddle-shaped skeletons,n egatively curved nanographenes exhibit relatively weak inter- molecular p-p interactions and good solubility in organic solvents;t hey also possess interesting nonlinear optical and electrochemical properties.R ecently,w er eported aw arped nanographene (WNG) with one five-membered ring and five seven-membered rings in the hexagonal lattice ( Figure 1b).…”