Three-Fold Scholl-Type Cycloheptatriene Ring Formation around a Tribenzotriquinacene Core: Toward Warped Graphenes

Abstract

A nonplanar polycyclic aromatic compound 6 bearing a tribenzotriquinacene (TBTQ) core merged with an o,p,o,p,o,p-hexaphenylene belt was prepared and characterized by NMR spectroscopy and X-ray crystallography. The key synthesis step involves three Scholl-type cycloheptatriene ring formation steps of the 1,4,8-tris(3',4'-dimethoxyphenyl)-TBTQ derivative 5. The bridging of each of the three TBTQ bays by 1,2-phenylene units in compound 6 gives rise to an unusual wizard hat shaped structure, which represents a promising key intermediate for the construction of nonplanar nanographene molecules bearing a TBTQ core.

Construction of Polycyclic π‐Conjugated Systems Incorporating an Azulene Unit Following the Oxidation of 1,8‐Diphenyl‐9,10‐bis(phenylethynyl)phenanthrene

“…Unlike alternant π‐conjugated systems, the non‐alternant structure of azulene contributes to the construction of peculiar π‐conjugated systems . In addition to the electronic perturbations of the alternant π‐conjugated systems, many three‐dimensional nanocarbon structures with curvature have been proposed by embedding pentagons or heptagons in the hexagonal honeycomb lattice . Thus, the embedding of an azulene core into alternant PAHs could change both the molecular geometry and the electronic properties of the original PAHs.…”

“…[19][20][21][22][23][24][25][26] In addition to the electronic perturbations of the alternant p-conjugated systems, many three-dimensional nanocarbon structuresw ith curvature have been proposed by embedding pentagons or heptagonsi nt he hexagonal honeycomb lattice. [5,[27][28][29][30][31] Thus, the embedding of an azulenec ore into alternant PAHs could change both the molecular geometry and the electronicp roperties of the originalP AHs. Despite recenti nterest in the structural and electronic perturbations from the incorporationo fo ne or more azuleneu nit(s)i nto pconjugated systems, [32][33][34] the development of ar elatively simple and efficient method to construct azulene-embedded PAHs remains av ery challenging issue due to the limited number of synthetic methodologies.…”

Synthetic Applications of Oxidative Aromatic Coupling—From Biphenols to Nanographenes

“…Attempts to synthesize a C 3 -symmetric analogue of 198 containing three HBC moieties failed. [218] Kuck, Chow,and co-workers have,however,reported the syntheses of other bowl-shaped derivatives of tribenzotriquinacene bearing threefold symmetry:c ompounds 199 [219,220] and 200 [221] (Figure 16). Tr iquinacene 199 was obtained in 37 %y ield from an unsymmetric triaryltribenzotriquinacene precursor by oxidative closure of three seven-membered rings upon treatment with DDQ/TfOH.…”

An Elusive Nonaromatic Goal behind the Centropolyindanes: Aufbau of Veratrolo‐Annelated Centropolyquinanes and Ozonolytic Abbau

“…This indicates that a number of further electron‐rich (multiply methoxylated) centropolyindane‐type polycyclic aromatic compounds may become accessible in the not‐too‐distant future. A very recent example is noteworthy in this context …”