Structurally uniform and atomically precise carbon nanostructures

Segawa, Y.; Ito, Hideto; Itami, Kenichiro

doi:10.1038/natrevmats.2015.2

Cited by 470 publications

(333 citation statements)

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“…stereoisomerism | macrocycles | carbon nanotubes | crystal structures | dynamic structures T he chemistry of hoop-shaped cycloarylenes (nanohoops) is being enriched by increasing variations in the molecular structures (1)(2)(3)(4). The structural diversity in the constitutional arylene panels has gradually increased by starting from cyclopara-phenylenes (CPP; Fig.…”

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confidence: 99%

“…The structural diversity in the constitutional arylene panels has gradually increased by starting from cyclopara-phenylenes (CPP; Fig. 1) with the most primordial panel being benzene (5)(6)(7), and the nanohoop chemistry is deepening our understanding of π-conjugated structures with belt-shaped, curved sp 2 -carbon networks that mimic single-wall carbon nanotubes (SWNTs) (8).…”

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confidence: 99%

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Stereoisomerism, crystal structures, and dynamics of belt-shaped cyclonaphthylenes

Sun

Suenaga

Sarkar

et al. 2016

Proc. Natl. Acad. Sci. U.S.A.

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The chemistry of a belt-shaped cyclic array of aromatic panels, a socalled "nanohoop," has increasingly attracted much interest, partly because it serves as a segmental model of single-wall carbon nanotubes with curved sp 2 -carbon networks. Although the unique molecular structure of nanohoops is expected to deepen our understanding in curved π-systems, its structural chemistry is still in its infancy despite structural variants rapidly accumulated over the past several years. For instance, structural characteristics that endow the belt shapes with rigidity, an important structural feature relevant to carbon nanotubes, have not been clarified to date. We herein report the synthesis and structures of a series of belt-shaped cyclonaphthylenes. Random synthesis methods using three precursor units with different numbers of naphthylene panels allowed us to prepare 6 congeners consisting of 6 to 11 naphthylene panels, and relationships between the rigidity and the panel numbers, i.e., molecular structures, were investigated. Fundamental yet complicated stereoisomerism in the belt-shaped structures was disclosed by mathematical methods, and dynamics in the panel rotation was revealed by dynamic NMR studies with the aid of theoretical calculations.T he chemistry of hoop-shaped cycloarylenes (nanohoops) is being enriched by increasing variations in the molecular structures (1-4). The structural diversity in the constitutional arylene panels has gradually increased by starting from cyclopara-phenylenes (CPP; Fig. 1) with the most primordial panel being benzene (5-7), and the nanohoop chemistry is deepening our understanding of π-conjugated structures with belt-shaped, curved sp 2 -carbon networks that mimic single-wall carbon nanotubes (SWNTs) (8).Composed of arylene panels connected via multiple singlebond linkages, the belt-shaped nanohoop structures pose a fundamental and important question related to the isomerism and persistency of the curved sp 2 -carbon networks (8). Previously, we synthesized the first, to our knowledge, belt-persistent nanohoops to demonstrate that large arylene panels, such as chrysene and anthanthrene, endowed the nanohoop molecules with belt persistency. The belt-shaped atropisomers of [4]cyclochrysenylenes ([4]CC) (9, 10) and [4]cycloanthanthrenylenes ([4]CA) (11) were separated and identified as discrete molecular entities (Fig. 1), and the atropisomerism uniquely originated from restricted sp 2 -sp 2 rotations due to macrocyclic ring strain (12). However, the experimental relationship between the structure and dynamics of the arylene rotations in the nanohoops remains unclear (13-16) and will add novel insight to biaryl atropisomerism with structural and historical importance (17-20). We herein report our first attempt to reveal the structure-dynamics relationship in belt-shaped nanohoop molecules via the synthesis of a series of [n]cyclo-amphi-naphthylenes ([n]CaNAP, n = 6-11; Fig. 1) (21). Albeit simple at first glance, the molecular structures were rich in structural chemistry including ...

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Stereoisomerism, crystal structures, and dynamics of belt-shaped cyclonaphthylenes

Sun

Suenaga

Sarkar

et al. 2016

Proc. Natl. Acad. Sci. U.S.A.

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“…Two-dimensional (2D) carbon-based materials have attracted enormous interest in recent decades due to their unique structures, intriguing properties, and versatile applications, [1][2][3][4] especially after the landmark advent of graphene. 5 With the combination of sp-, sp 2 -, and sp 3 -hybridized carbon atoms, a number of 2D carbon materials with different architectures have also been synthesized and/or theoretically predicted.…”

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confidence: 99%

“…5 With the combination of sp-, sp 2 -, and sp 3 -hybridized carbon atoms, a number of 2D carbon materials with different architectures have also been synthesized and/or theoretically predicted. 2,[6][7][8][9][10][11][12][13][14][15][16][17][18] In particular, graphene has attracted major attention during the last decade, which also stimulated the studies of other 2D carbon materials such as γ-graphyne and graphdiyne ( Figure 1). 10,11,14,19,20 Atomically precise syntheses of γ-graphyne and graphdiyne remain elusive, but widely studied phenylene-ethynylene-based macrocycles can be regarded as their molecular subunits.…”

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“…Nevertheless, the number of reported examples of 2D carbon materials is still limited. 2,[6][7][8][9][10][11][12][13][14][15][16][17][18] By replacing ethynylene groups of γ-graphyne and graphdiyne with p-phenylene units, two purely sp 2 -hybridized 2D carbon structures with hexagonal symmetry can be conceived, which we name graphenylene-1 and graphenylene-2, respectively ( Figure 1). Notably, graphenylene-1 corresponds to a single-layer substructure of the hypothetical carbon allotrope "cubic graphite", 26 the synthesis of which still remains elusive.…”

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A Shape-Persistent Polyphenylene Spoked Wheel

et al. 2016

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A shape-persistent polyphenylene with a “spoked wheel” structure was synthesized as a subunit of an unprecedented two-dimensional polyphenylene that we name graphenylene. The synthesis was carried out through a sixfold intramolecular Yamamoto coupling of a dodecabromo-substituted dendritic polyphenylene precursor, which had a central hexaphenylbenzene unit as a template. Characterizations by NMR spectroscopy and matrix-assisted laser ionization time-of-flight mass spectrometry provided an unambiguous structural proof for the wheel-like molecule with a molar mass of 3815.4 g/mol. Remarkably, scanning tunneling microscopy visualization clearly revealed the defined spoked wheel structure of the molecule with six internal pores.

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Talking to Cells: Semiconductor Nanomaterials at the Cellular Interface

Rotenberg

Tian

2018

Adv. Biosys.

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The interface of biological components with semiconductors is a growing field with numerous applications. For example, the interfaces can be used to sense and modulate the electrical activity of single cells and tissues. From the materials point of view, silicon is the ideal option for such studies due to its controlled chemical synthesis, scalable lithography for functional devices, excellent electronic and optical properties, biocompatibility and biodegradability. Recent advances in this area are pushing the bio-interfaces from the tissue and organ level to the single cell and sub-cellular regimes. In this progress report, we will describe some fundamental studies focusing on miniaturizing the bioelectric and biomechanical interfaces. Additionally, many of our highlighted examples involve freestanding silicon-based nanoscale systems, in addition to substrate-bound structures or devices; the former offers new promise for basic research and clinical application. In this report, we will describe recent developments in the interfacing of neuronal and cardiac cells and their networks. Moreover, we will briefly discuss the incorporation of semiconductor nanostructures for interfacing non-excitable cells in applications such as probing intracellular force dynamics and drug delivery. Finally, we will suggest several directions for future exploration.

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Structurally uniform and atomically precise carbon nanostructures

Cited by 470 publications

References 163 publications

Stereoisomerism, crystal structures, and dynamics of belt-shaped cyclonaphthylenes

Stereoisomerism, crystal structures, and dynamics of belt-shaped cyclonaphthylenes

A Shape-Persistent Polyphenylene Spoked Wheel

Talking to Cells: Semiconductor Nanomaterials at the Cellular Interface

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