Properties of Sizeable [<i>n</i>]Cycloparaphenylenes as Molecular Models of Single‐Wall Carbon Nanotubes Elucidated by Raman Spectroscopy: Structural and Electron‐Transfer Responses under Mechanical Stress

Peña-Álvarez, Miriam; Burrezo, Paula Mayorga; Kertész, Miklós; Iwamoto, Takahiro; Yamago, Shigeru; Xia, Jianlong; Jasti, Ramesh; Navarrete, Juan T. López; Taravillo, Mercedes; Baonza, Valentı́n G.; Casado, Juan

doi:10.1002/ange.201400719

Cited by 26 publications

(4 citation statements)

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“…Several bands in this region are assigned either as CCC bending modes or radial flexural modes, in addition to the typical pseudo radial breathing modes and the radial breathing modes, p-RBM and RBM, respectively). 43,44 In line with the findings in CNTs, the p-RBM intensity decays with increasing pressure for all [n]CPPs. The new information here is that since in [n]CPPs the p-RBM bands are measured in out-of-resonant conditions, their intensity decays as the result of an intrinsic increase of fluorescence/reabsorption during compression, and not due to resonance effects.…”

Section: Resultssupporting

confidence: 85%

“…Similarly to the G bands, these trends also display an approximately linear relationship between upshift and increasing pressure with the rates changing at around the same values for each n. These Raman bands are the combination of CC and CH bending modes, and consequently, the change in the rate might be ascribed to changes in torsions as ovalization develops. 43,44 In addition, as shown in Figure 3, Table S1, and Figure S1, the S1,i and S2,i coefficients of the five 1250 cm -1 bands depend on the nanohoop size n, unlike those for linear oligo-paraphenylenes which are nearly independent from n. 47 The pressure coefficients for the low frequency modes are detailed in the supplementary material file.…”

Section: Resultsmentioning

confidence: 99%

“…We mainly focus the discussion on the GA1g and GE2g bands around 1580 cm − related to the collective CC stretching modes. 43,44 These modes provide information on -electron delocalization and aromaticity. A general observation is that all Raman bands upshift with increasing pressure.…”

Section: Resultsmentioning

confidence: 99%

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Molecules under Pressure: The Case of [n]Cycloparaphenylenes

et al. 2018

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High pressures in the 0-10 GPa range cause molecules to deform in unusual ways. A series of precisely defined carbon nanohoops consisting of n para-linked phenyl groups, [n]cycloparaphenylenes ([n]CPPs, n=7, 8, 9, 10, and 12) were studied in this pressure range using Raman spectroscopy and Density Functional Theory (DFT), and compared with more rigid smaller 5-and [6]CPPs and with the longer carbon nanotubes. The presented analysis sheds light on the different responses to pressure depending on the nanohoop size. Surprisingly, the pressure coefficients, the rate of the Raman shifts as a function of pressure, change at a particular pressure which is characteristic of each [n]CPP. We identified this pressure as the beginning of ovalization of the nanohoops in analogy to carbon nanotubes. This pressure induced ovalization is reversible in the range of pressure studied for [n]CPPs with n=7, 9, 10, and 12. In the case of [8]CPP, we find a metastable conformation at 8 GPa with significantly changed dihedral angles of adjacent phenyls. This high pressure molecular phase of [8]CPP provides an example for a new mechanism of irreversibility involving different conformations upon high pressure treatment. Modeling provided atomic level insights into the changes of conformations and the development of aromatic vs quinonoid structures as a function of pressure.

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confidence: 85%

Section: Resultsmentioning

confidence: 99%

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Molecules under Pressure: The Case of [n]Cycloparaphenylenes

et al. 2018

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“…Inspired by the structural unit of SWCNTs, organic molecules with hoop‐shaped π‐conjugated systems, such as cycloparaphenylenes (CPPs), have attracted a great attention due to their interesting curved structures and physical properties, which were envisioned as precursors for the bottom‐up synthesis of SWCNTs with desired chirality. [ 151,162‐180 ] Isobe et al . synthesized the finite units of (12,8), (11,9), and (10,10) SWCNTs from [4]phenacene.…”

Section: Templated Synthesis Of Carbon Nanotubes From Carbon Segmentsmentioning

confidence: 99%

Precise Synthesis of Carbon Nanotubes and One‐Dimensional Hybrids from Templates^†

et al. 2021

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Carbon nanotubes (CNTs) present unique properties determined by their chiral structure. The main hurdle towards the wide applications is the difficulty to control the structure of CNTs and their hybrids that determines the properties. Precise synthesis with well-defined templates is a promising approach to control the identical structure of carbon nanomaterials. In this review, we summarize main achievements on controlled synthesis of CNTs and hybrids on two aspects: chirality-specific growth of CNTs from well-defined catalysts and nanocarbon templates, atomically precise synthesis of one-dimensional (1D) materials with the templates of CNTs. In the chirality-controlled growth part, we focus on the design of structural templates and growth mechanisms. In the synthesis of CNT hybrids part, we organize the existing strategies based on types of 1D hybrids templated by CNTs, including confined nanotubes, linear carbon chains, nanowires, quasi-1D van der-Waals materials. The main advantages, challenges, and perspectives in further development are discussed.Xusheng Yang (top left) received his B.S. degree at Lanzhou University in 2019 and now is a M.S. candidate under Prof.

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Open‐Shell Characters, Aromaticities and Third‐Order Nonlinear Optical Properties of Carbon Nanobelts Composed of Five‐ and Six‐Membered Rings

et al. 2018

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Geometric features, electronic structures and third‐order nonlinear optical (NLO) properties of belt‐shaped hydrocarbons, namely, carbon nanobelts, are investigated by using the density functional theory (DFT) methods. A carbon nanobelt composed of five‐ and six‐membered rings (IF‐CNB, 42π), which involves repeating indenofluorene (IF) units, is expected to exhibit both open‐shell multiradical character and relatively strong aromatic nature in the singlet state, while that composed only of six‐membered rings (CNB, 48π) is shown to be a closed‐shell weak antiaromatic species. These features of electronic structure of IF‐CNB are shown to be closely related to its p‐quinodimethane (pQM)‐like substructures and several geometric features (bond‐length alternations and symmetry) of the system. Third‐order NLO properties of open‐shell IF‐CNB is expected to be enhanced more than three times as large as those of the closed‐shell CNB. These results indicate the possibility of further multi‐functionalizations of belt‐shaped hydrocarbons by fusing five‐membered rings.

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Properties of Sizeable [n]Cycloparaphenylenes as Molecular Models of Single‐Wall Carbon Nanotubes Elucidated by Raman Spectroscopy: Structural and Electron‐Transfer Responses under Mechanical Stress

Cited by 26 publications

References 57 publications

Molecules under Pressure: The Case of [n]Cycloparaphenylenes

Molecules under Pressure: The Case of [n]Cycloparaphenylenes

Precise Synthesis of Carbon Nanotubes and One‐Dimensional Hybrids from Templates^†

Open‐Shell Characters, Aromaticities and Third‐Order Nonlinear Optical Properties of Carbon Nanobelts Composed of Five‐ and Six‐Membered Rings

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Properties of Sizeable [n]Cycloparaphenylenes as Molecular Models of Single‐Wall Carbon Nanotubes Elucidated by Raman Spectroscopy: Structural and Electron‐Transfer Responses under Mechanical Stress

Cited by 26 publications

References 57 publications

Molecules under Pressure: The Case of [n]Cycloparaphenylenes

Molecules under Pressure: The Case of [n]Cycloparaphenylenes

Precise Synthesis of Carbon Nanotubes and One‐Dimensional Hybrids from Templates†

Open‐Shell Characters, Aromaticities and Third‐Order Nonlinear Optical Properties of Carbon Nanobelts Composed of Five‐ and Six‐Membered Rings

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Product

Resources

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Precise Synthesis of Carbon Nanotubes and One‐Dimensional Hybrids from Templates^†