Quadruply BN‐Fused Tetrathia[8]circulenes with Flexible Frameworks: Synthesis, Structures and Properties

Abstract

Quadruply BN-fused tetrathia [8]circulenes were synthesized through four-fold electrophilic borylation. The single-crystal X-ray diffraction analysis revealed that the BNfused tetrathia[8]circulene with peripheral phenyl groups exhibits crystal polymorphism, in which the circulene core adopts both planar and saddle conformations in the solid state. The experimental and theoretical studies revealed that the weaker aromaticity of azaborine compared with benzene renders the flexibility of the BN-fused tetrathia[8]circulenes.

Theoretical study on the structures, electronic properties, and aromaticity of thia[4]circulenes

“…[42][43][44] Additionally, various thia [8]circulene derivatives are known to exhibit other unique properties such as association behavior, aggregation-induced emission, and efficient intersystem crossing. 29,[45][46][47][48][49][50][51] However, except for thia [8]circulenes, thia[n]circulenes consisting only of thiophene rings remain hypothetical molecules. To access the structures, electronic properties, and aromaticity of other thia[n]circulenes and their derivatives, there exist a vast number of theoretical studies.…”

Protonation‐Induced Antiaromaticity in Octaaza[8]circulenes: Cyclooctatetraene Scaffolds Constrained with Four Amidine Moieties

“…Hetero[8]circulenes are polycyclic heteroaromatic molecules in which the central eight‐membered ring is surrounded by eight fused benzene and heteroaromatic rings (Figure 2a) [30–63] . The aromaticity of hetero[8]circulenes has attracted considerable attention because the central eight‐membered ring can be regarded as an 8π antiaromatic planar cyclooctatetraene (COT) [64–69] .…”