Planar Anthracene–Acetylene Frameworks as a Stereogenic Motif

Abstract

Planar and rigid frameworks that consist of two 1,8‐substituted anthracene units and two acetylene linkers were utilized as key structures for the generation of stereoisomers through the introduction of extra substituents. These compounds were synthesized from 1,8‐substituted anthracene building units by a combination of coupling reactions. We designed diastereomers, enantiomers, and topomers by modifying the combination of the two linkers and the number of substituents at sterically crowded intraannular positions. The molecular structures, stereochemistry, and properties of these compounds were investigated by means of spectroscopic techniques and theoretical calculations. A prochiral cyclic dimer with one extraannular substituent was designed to generate a stereochemical phenomenon in two dimensions. Scanning tunneling microscopy measurements revealed that the molecules formed a self‐assembled monolayer at the liquid–solid interface in a conglomerate‐type manner. The scope and potential of the macrocyclic frameworks in studies of π‐conjugated compounds are presented.

Triple and Quadruple Triptycene Gears in Rigid Macrocyclic Frameworks

“…For calculations of molecules involving π‐electron interactions, the choice of the calculation level is essential. Systematic theoretical studies by Truhlar's group as well as our previous studies on the calculations of anthracene macrocyclic compounds and the gear system of 6 [5d] suggested that some Minnesota family functionals reasonably reproduced the experimental data by considering the π ··· π and related interactions suitably within acceptable computational times. In contrast, the B3LYP functional, one of the most common functionals, considerably underestimated such interactions without dispersion terms.…”

“…To evaluate the overall interactions between the Tp units in the macrocyclic compounds, we calculated thermochemical data by using homodesmotic (HD) reactions , . We designed the HD reactions shown in Scheme , for which the reactants were a macrocyclic compound (or its model) and ethyne ( 20 ), and the products were 9,10‐diethynyl‐Tp and 1,2‐diethynylbenzene ( 21 ).…”

π‐Conjugated Macrocycles Bearing Angle‐Strained Alkynes

“…The selected examples of strained macrocycles are depicted in Figure . Fan‐blade‐shaped macrocycle 187 was synthesized as a racemic mixture by Eglinton coupling . The pure enantiomer could be resolved by using chiral high‐performance liquid chromatography.…”

“…Fan-blade-shaped macrocycle 187 was synthesized as ar acemic mixture by Eglinton coupling. [305][306][307][308] The pure enantiomer could be resolved by using chiral high-performance liquid chromatography. DFT calculations pointed out that the macrocyclic structure is slightly distorted because of the stericr epulsion between ah ydrogen atom and am ethoxy group inside the macrocyclic ring.…”

N-Cyanomethylmethanimine tethered anthracene dimer: concise synthesis, conformational properties and photoinduced configurational isomerization

“…16 So far, tethered anthracene dimers reported in the literature contain diverse linker groups, ranging from p-conjugated bridges (e.g., phenylenes, phenylacetylenes, oligoynes) to non-conjugated ethers, urea, ester, and sulfur groups. Depending on the shape and number of linker groups, the structures of tethered anthracene dimers can be divided into three types, namely linear, 17,18 bent, [19][20][21] and macrocyclic [22][23][24][25] (see Fig. 1A).…”