Five‐Fold Symmetric Pentaindolo‐ and Pentakis(benzoindolo)Corannulenes: Unique Structural Dynamics Derived from the Combination of Helical and Bowl Inversions

Abstract

Peripherally p-extended corannulenes bearing quintuple azahelicene units, 10 and 11,w ere prepared and their dynamic behaviors were studied experimentally and theoretically.T he fused corannulenes were synthesized from sympentabromocorannulene in three steps.X -Rayd iffraction analysis for 10 displayed aconformer possessing aP(M) bowl chirality and aP PMPM (PMPMM) helical chirality,w hich was found to be the most stable conformer(s). Variabletemperature NMR measurements of 10 and 11 revealed that their structural isomers can be interconvertible in solution, depending on the steric congestion around the helical scaffolds. Automated search for conformers in the equilibrium and transition states by Artificial Force Induced Reaction (AFIR) method revealed their interconversion networks,i ncluding bowl-inversion and helical-inversion. This analysis indicated that the co-existing corannulene and azahelicene moieties influence the conformational dynamics,w hich leads to mitigation of the activation energy barriers for isomerization.

Pushing Up the Size Limit of Boron‐doped peri‐Acenes: Modular Synthesis and Characterizations

“…In their solid states, the unit cell of 1 a‐1 contains two enantiomers with helical chirality ( M : green color; P : orange color) and they pack into an ordered head‐to‐tail columnar arrangement along the c ‐axis, where the distances between two enantiomers are in the range of 3.41 to 3.67 Å (Figure 3d). Interestingly, 1 a‐2 displays unique bowl chirality due to its reflection asymmetric feature and the steric repulsion caused by the substituents along the zigzag edges [29–32] . To the best of our knowledge, this is the first example of tricoordinate B‐doped polycyclic aromatic hydrocarbons (PAHs) with bowl chirality (Figure 3e).…”

“…Interestingly, 1 a-2 displays unique bowl chirality due to its reflection asymmetric feature and the steric repulsion caused by the substituents along the zigzag edges. [29][30][31][32] To the best of our knowledge, this is the first example of tricoordinate B-doped polycyclic aromatic hydrocarbons (PAHs) with bowl chirality (Figure 3e). In the crystal packing, two enantiomers (M and P) of 1 a-2 form the face-to-face π-stacked dimer structure in its unit cell with a distance of 3.24 Å, and the unit cell is further arranged into an ordered columnar superstructure.…”

Multiple [n]helicenes with various aromatic cores

“…As shown in Fig. 15, Tanaka et al 42 synthesized two nitrogen-doped quintuple helicenes, 42 and 43 , in three key steps. Firstly, a five-fold Buchwald–Hartwig reaction between pentabromocorannulene and aromatic amines afforded precursors 40 and 41 .…”

Extended Quinolizinium-Fused Corannulene Derivatives: Synthesis and Properties

“…The most commonly found examples are those with nitrogen atoms at the peripheral positions or within the polycyclic skeleton (Figure ). − …”