Cramping an Alkyl Group by Rigid Macrocyclic Framework

Toyota, Shinji; Oki, Tomohiro; Inoue, Masataka; Wakamatsu, Kan; Iwanaga, Takeshi

doi:10.1246/cl.150340

Cited by 16 publications

(13 citation statements)

References 19 publications

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“…Because the rotation of the Mes groups relative to the anthracene moieties, which might lead to the site exchange, is completely frozen on the NMR time scale (ca. 200 kJ mol −1 for 9‐mesitylanthracene), the observed dynamic process is attributable to the macrocyclic framework itself.…”

Section: Figurementioning

confidence: 92%

Macrocyclic 2,7‐Anthrylene Oligomers

Yamamoto

Wakamatsu

Iwanaga

et al. 2016

Chemistry An Asian Journal

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A macrocyclic compound consisting of six 2,7-anthrylene units was successfully synthesized by Ni-mediated coupling of the corresponding dibromo precursor as a novel π-conjugated compound. This compound was sufficiently stable and soluble in organic solvents due to the presence of mesityl groups. X-ray analysis showed that the molecule had a nonplanar and hexagonal wheel-shaped framework of approximately S6 symmetry. The dynamic process between two S6 structures was observed by using the dynamic NMR technique, the barrier being 58 kJ mol(-1) . The spectroscopic properties of the hexamer were compared with those of analogous linear oligomers.

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Section: Figurementioning

confidence: 92%

Macrocyclic 2,7‐Anthrylene Oligomers

Yamamoto

Wakamatsu

Iwanaga

et al. 2016

Chemistry An Asian Journal

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“…However, because this molecule lacked a probe that would allow observation of the direction of the ethyl group by means of NMR spectroscopy, we introduced a mesityl group at the 10‐position of the anthracene unit. Because the rotation of the mesityl group in 5 b′ (Et) should be practically frozen even at a high temperature (an estimated barrier of 200 kJ mol −1 ), the equivalence of the two o ‐Me groups should give information on the direction of the ethyl group. This mesityl group is also important for the solubility and stability enhancement .…”

Section: Molecular Designs Of Stereogenic Structuresmentioning

confidence: 99%

Planar Anthracene–Acetylene Frameworks as a Stereogenic Motif

2017

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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.

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“…In a 9‐mesitylanthracene unit, the rotation of the Mes group relative to the anthracene plane is highly restricted due to severe steric hindrance (barrier ca. 200 kJ mol −1 ) . We applied this stereochemical feature to the conformational analysis of X5 and 1 , where the direction of the ethyl group was detected by NMR spectral measurements of the latter .…”

Section: Introductionmentioning

confidence: 99%

“…200 kJ mol −1 ) . We applied this stereochemical feature to the conformational analysis of X5 and 1 , where the direction of the ethyl group was detected by NMR spectral measurements of the latter . We utilized this versatile building unit, 10‐mesitylanthracene‐1,8‐diyl unit, for the construction of a series of cyclic structures.…”

Section: Introductionmentioning

confidence: 99%

“…[2,7] We applied this stereochemical feature to the conformational analysis of X5 and 1, where the direction of the ethyl group was detected by NMR spectral measurements of the latter. [1,2] We utilized this versatile building unit, 10-mesitylanthracene-1,8-diyl unit, for the construction of a series of cyclic structures. We herein report the synthesis, structures, and properties of cyclic oligomers Xn consisting of n anthracene units and n diacetylene linkers.…”

Section: Introductionmentioning

confidence: 99%

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Chemistry of Anthracene−Acetylene Oligomers XXVII. Iterative Synthesis, Structures, and Properties of Anthracene−Diacetylene Cyclic Oligomers with 10‐Mesitylanthracene‐1,8‐diyl Units

et al. 2018

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A series of cyclic oligomers consisting of 10‐mesitylanthracene‐1,8‐diyl units and diacetylene linkers were synthesized as soluble π‐conjugated compounds. Macrocyclic frameworks from dimer to octamer except heptamer were constructed from 1,8‐diethynylanthracene derivatives by iterative coupling reactions. The rigid structure of the dimer, the strained structures of the trimer and the pentamer, and the belt‐shaped structures of the other even‐numbered oligomers were revealed by X‐ray analysis and DFT calculations. The dynamic behavior of the cyclic oligomers was analyzed by observing variable‐temperature 1H NMR spectra. The UV/Vis and fluorescence spectra of these emissive cyclic compounds are discussed on the basis of the molecular structures.

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Cramping an Alkyl Group by Rigid Macrocyclic Framework

Cited by 16 publications

References 19 publications

Macrocyclic 2,7‐Anthrylene Oligomers

Macrocyclic 2,7‐Anthrylene Oligomers

Planar Anthracene–Acetylene Frameworks as a Stereogenic Motif

Chemistry of Anthracene−Acetylene Oligomers XXVII. Iterative Synthesis, Structures, and Properties of Anthracene−Diacetylene Cyclic Oligomers with 10‐Mesitylanthracene‐1,8‐diyl Units

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