Helically Arranged Chiral Molecular Nanographenes

Izquierdo‐García, Patricia; Fernández‐García, Jesús M.; Fernández, Israel; Perles, Josefina; Martín, Nazario

doi:10.1021/jacs.1c05977

Cited by 37 publications

(24 citation statements)

References 50 publications

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“…In addition, CNBs containing heteroatoms and nonhexagonal rings were also prepared. The second type of interesting carbon nanostructures are the helical nanographenes and graphene nanoribbons, in which one or more helicene units are fused into a contiguous polycyclic aromatic hydrocarbon framework. The chirality thus has a similar origin to that of the traditional helicenes, and the racemization energy is mainly determined by steric hindrance between the ortho -fused aromatic units.…”

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confidence: 99%

Synthesis and Chiral Resolution of Twisted Carbon Nanobelts

et al. 2021

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Twisted carbon nanobelts could display persistent chirality, which is desirable for material applications, but their synthesis is very challenging. Herein, we report the successful synthesis and chiral resolution of such a kind of molecules (1-H and 1) with a figure-eight configuration. 1-H was synthesized first by macrocyclization through Suzuki coupling reaction followed by benzannulation via Bi(OTf)3-mediated cyclization reaction of vinyl ether. Oxidative dehydrogenation of 1-H gave the fully π-conjugated 1. Their twisted structures were confirmed by X-ray crystallographic analysis and calculations, and they can be resolved by chiral high-performance liquid chromatography. The isolated enantiomers showed persistent chiroptical properties according to the circular dichroism measurements, with moderate |g abs| values (0.0016 for 1-H and 0.005–0.007 for 1). Their photophysical properties were also briefly studied.

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confidence: 99%

Synthesis and Chiral Resolution of Twisted Carbon Nanobelts

et al. 2021

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“…It is worth noting that direct dehydrocyclization of a polyphenylene analogue of precursor 79 did not result in 80 under various oxidative conditions. Unlike 78 being synthesized with formation of 12 C–C bonds, helical polycyclic arenes 81a – c were synthesized in yields of 70–80% by treatment of the corresponding substrates with DDQ/CF 3 SO 3 H at 0 °C . In this Scholl reaction, only 8 C–C bonds were formed because the central benzene ring was substituted with four fluorine atoms and thus could not undergo cyclodehydrogenation.…”

Section: Synthesis Of Curved Polycyclic Aromatics Through Scholl Reac...mentioning

confidence: 99%

The Scholl Reaction as a Powerful Tool for Synthesis of Curved Polycyclic Aromatics

2022

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The past decade has witnessed remarkable success in the synthesis of curved polycyclic aromatics through Scholl reactions which enable oxidative aryl–aryl coupling even in company with the introduction of significant steric strain. These curved polycyclic aromatics are not only unique objects of structural organic chemistry in relation to the nature of aromaticity but also play an important role in bottom-up approaches to precise synthesis of nanocarbons of unique topology. Moreover, they have received considerable attention in the fields of supramolecular chemistry and organic functional materials because of their interesting properties and promising applications. Despite the great success of Scholl reactions in synthesis of curved polycyclic aromatics, the outcome of a newly designed substrate in the Scholl reaction still cannot be predicted in a generic and precise manner largely due to limited understanding on the reaction mechanism and possible rearrangement processes. This review provides an overview of Scholl reactions with a focus on their applications in synthesis of curved polycyclic aromatics with interesting structures and properties and aims to shed light on the key factors that affect Scholl reactions in synthesizing sterically strained polycyclic aromatics.

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“…The resulting chiroptical features, such as circular dichroism and circularly polarized luminescence, are fascinating and have been studied for circularly polarized organic light-emitting diodes and chiral bioimaging applications. , Chiral molecules not only interact with photons to produce chiroptical signals but also influence the spins of the electrons passing through the structures . This phenomenon, known as the chiral-induced spin-selectivity effect, has many potential applications in, for example, biorecognition as well as spintronics. − Combinations of NGs and helicenes are therefore attracting increasing attention, and NGs can provide high hole mobility and an extra platform for chemical modifications. − The chemistry of NGs, especially the cyclodehydrogenation reaction, has played a key role in substantially extending the π-conjugated systems of helicenes. This has provided multiple helical edges in NGs, such as hexapole [9]helicene 45 and supertwistacene 46 (Figure ).…”

Section: Rising From Flatlandmentioning

confidence: 99%

Nanographenes and Graphene Nanoribbons as Multitalents of Present and Future Materials Science

2022

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As cut-outs from a graphene sheet, nanographenes (NGs) and graphene nanoribbons (GNRs) are ideal cases with which to connect the world of molecules with that of bulk carbon materials. While various top-down approaches have been developed to produce such nanostructures in high yields, in the present perspective, precision structural control is emphasized for the length, width, and edge structures of NGs and GNRs achieved by modern solution and on-surface syntheses. Their structural possibilities have been further extended from “flatland” to the three-dimensional world, where chirality and handedness are the jewels in the crown. In addition to properties exhibited at the molecular level, self-assembly and thin-film structures cannot be neglected, which emphasizes the importance of processing techniques. With the rich toolkit of chemistry in hand, NGs and GNRs can be endowed with versatile properties and functions ranging from stimulated emission to spintronics and from bioimaging to energy storage, thus demonstrating their multitalents in present and future materials science.

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Helically Arranged Chiral Molecular Nanographenes

Cited by 37 publications

References 50 publications

Synthesis and Chiral Resolution of Twisted Carbon Nanobelts

Synthesis and Chiral Resolution of Twisted Carbon Nanobelts

The Scholl Reaction as a Powerful Tool for Synthesis of Curved Polycyclic Aromatics

Nanographenes and Graphene Nanoribbons as Multitalents of Present and Future Materials Science

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