Helicene-based π-conjugated macrocycles: their synthesis, properties, chirality and self-assembly into molecular stripes on a graphite surface

Result code in IS VaVaI

<a href="https://www.isvavai.cz/riv?ss=detail&h=RIV%2F61388963%3A_____%2F23%3A00564865" target="_blank" >RIV/61388963:_____/23:00564865 - isvavai.cz</a>

Alternative codes found

RIV/68378271:_____/23:00564865 RIV/68407700:21230/23:00361348 RIV/00216208:11310/23:10470089

Result on the web

<a href="https://doi.org/10.1039/D2NR04209F" target="_blank" >https://doi.org/10.1039/D2NR04209F</a>

DOI - Digital Object Identifier

<a href="http://dx.doi.org/10.1039/d2nr04209f" target="_blank" >10.1039/d2nr04209f</a>

Result language

angličtina

Original language name

Helicene-based π-conjugated macrocycles: their synthesis, properties, chirality and self-assembly into molecular stripes on a graphite surface

Original language description

Fully aromatic helicenes are attractive building blocks for the construction of inherently chiral π-conjugated macrocyclic nanocarbons. These hitherto rare molecular architectures are envisaged to exhibit remarkable (chir)optical properties, self-assembly, charge/spin transport, induced ring current or a fascinating Möbius topology. Here the synthesis of helically chiral macrocycles that combine angular dibenzo[5]helicene units as corners and linear trans-stilbene-4,4′-diyl linkers as edges is reported. By subjecting a racemic or enantiopure divinyl derivative of dibenzo[5]helicene to olefin metathesis, which was catalysed by a 2nd generation Piers catalyst under kinetic control, a π-conjugated helicene cyclic trimer (33%) and a tetramer (22%) were obtained, which were separated by GPC. Combining racemic/asymmetric synthesis with the resolution of enantiomers/diastereomers by SFC/HPLC on a chiral column, both homochiral (+)-(M,M,M)/(−)-(P,P,P) and heterochiral (+)-(M,M,P)/(−)-(M,P,P) stereoisomers of the helicene cyclic trimer could be obtained in an enantio- and diastereomerically enriched form. The complete energy profile of their interconversion was compiled on the basis of kinetic measurements and numerical solution of the proposed kinetic model. In equilibrium, the heterochiral diastereomer predominates over the homochiral one (ca. 75 : 25 at 76 °C). π-Conjugation along a large, twisted circuit in the helicene cyclic trimer is rather disrupted, stabilising this formally antiaromatic molecule. Using an optimised PeakForce mode of ambient AFM, the self-assembly of otherwise highly mobile stereoisomers of the helicene cyclic trimer on the HOPG surface could be studied. Irrespective of the stereochemistry, strong preferences for the edge-to-edge interaction of these macrocycles were found to form very long parallel 1D molecular stripes in ordered 2D nanocrystals, a result also supported by molecular dynamics simulations. Six trityl groups, initially introduced to the macrocycle to enhance solubility, serve as a key “molecular Velcro” system in the self-assembly of macrocycles to maximise their mutual van der Waals interactions.

Czech name

—

Czech description

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Type

J_imp - Article in a specialist periodical, which is included in the Web of Science database

CEP classification

—

OECD FORD branch

10401 - Organic chemistry

Project

Result was created during the realization of more than one project. More information in the Projects tab.

Continuities

I - Institucionalni podpora na dlouhodoby koncepcni rozvoj vyzkumne organizace

Publication year

2023

Confidentiality

S - Úplné a pravdivé údaje o projektu nepodléhají ochraně podle zvláštních právních předpisů

Name of the periodical

Nanoscale

ISSN

2040-3364

e-ISSN

2040-3372

Volume of the periodical

15

Issue of the periodical within the volume

4

Country of publishing house

GB - UNITED KINGDOM

Number of pages

12

Pages from-to

1542-1553

UT code for WoS article

000885656700001

EID of the result in the Scopus database

2-s2.0-85142525577