Carbon Nanotube for Imaging of Single Molecules in Motion

Nakamura, Eiichi

doi:10.1002/9780470660188.ch16

Cited by 6 publications

(3 citation statements)

References 9 publications

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“…This is largely because the major source of our conformational knowledge relies on the measurement of time-and molecular-average of ensembles as demonstrated by spectroscopic and crystallographic analyses. We have expended considerable effort over a long time, 3,4 to study the structure of single molecules 5 and molecular clusters 6 and their evolution over time (conformation, reaction 7 and catalysis 8 ), by recording movies of molecules and molecular clusters in vacuum by atomic resolution transmission electron microscopy (TEM), as illustrated by a real-time movie of two wobbling hydrocarbon chains in a single molecule located in a carbon nanotube (CNT), first reported in 2007. 9 The images in this single-molecule real-time TEM (SMRT-TEM) movie were often blurred because the motion was faster than the speed of the image acquisition on the charge-coupled device (CCD) camera (0.5 s).…”

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confidence: 99%

Conformational Analysis of Single Perfluoroalkyl Chains by Single-Molecule Real-Time Transmission Electron Microscopic Imaging

et al. 2013

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Whereas a statistical average of molecular ensembles has been the conventional source of information on molecular structures, atomic resolution movies of single organic molecules obtained by single-molecule real-time transmission electron microscopy have recently emerged as a new tool to study the time evolution of the structures of individual molecules. The present work describes a proof-of-principle study of the determination of the conformation of each C-C bond in single perfluoroalkyl fullerene molecules encapsulated in a single-walled carbon nanotube (CNT) as well as those attached to the outer surface of a carbon nanohorn (CNH). Analysis of 82 individual molecules in CNTs under a 120 kV electron beam indicated that 6% of the CF2-CF2 bonds and about 20% of the CH2-CH2 bonds in the corresponding hydrocarbon analogue are in the gauche conformation. This comparison qualitatively matches the known conformational data based on time- and molecular-average as determined for ensembles. The transmission electron microscopy images also showed that the molecules entered the CNTs predominantly in one orientation. The molecules attached on a CNH surface moved more freely and exhibited more diverse conformation than those in a CNT, suggesting the potential applicability of this method for the determination of the dynamic shape of flexible molecules and of detailed conformations. We observed little sign of any decomposition of the specimen molecules, at least up to 10(7) e·nm(-2) (electrons/nm(2)) at 120 kV acceleration voltage. Decomposition of CNHs under irradiation with a 300 kV electron beam was suppressed by cooling to 77 K, suggesting that the decomposition is a chemical process. Several lines of evidence suggest that the graphitic substrate and the attached molecules are very cold.

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Section: ■ Introductionmentioning

confidence: 99%

Conformational Analysis of Single Perfluoroalkyl Chains by Single-Molecule Real-Time Transmission Electron Microscopic Imaging

et al. 2013

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“…We have so far filmed movies of hydrocarbons, amide, biotin, van der Waals molecular clusters, chemical reactions, and metal catalysis . Some of these movies were collected and published recently. , …”

Section: Introductionmentioning

confidence: 99%

“…7 Some of these movies were collected and published recently. 8,9 It is important to note at this juncture that the CNT underwent frequent and seemingly random thermal vibration of sub-nanometer magnitude like a waving pole, but these events were eliminated visually from the movies by normalization for the position of the CNT so that we can focus on the molecular motions. The motions of CNTs are an important element of the SMART-TEM studies because they cause motions of the attached molecules that occurred randomly or probabilistically.…”

Section: Introductionmentioning

confidence: 99%

Atomic-Resolution Transmission Electron Microscopic Movies for Study of Organic Molecules, Assemblies, and Reactions: The First 10 Years of Development

Nakamura

2017

Acc. Chem. Res.

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A molecule is a quantum mechanical entity. "Watching motions and reactions of a molecule with our eyes" has therefore been a dream of chemists for a century. This dream has come true with the aid of the movies of atomic-resolution transmission electron microscopic (AR-TEM) molecular images through real-time observation of dynamic motions of single organic molecules (denoted hereafter as single-molecule atomic-resolution real-time (SMART) TEM imaging). Since 2007, we have reported movies of a variety of single organic molecules, organometallic molecules, and their assemblies, which are rotating, stretching, and reacting. Like movies in the theater, the atomic-resolution molecular movies provide us information on the 3-D structures of the molecules and also their time evolution. The success of the SMART-TEM imaging crucially depends on the development of "chemical fishhooks" with which fish (organic molecules) in solution can be captured on a single-walled carbon nanotube (CNT, serving as a "fishing rod"). The captured molecules are connected to a slowly vibrating CNT, and their motions are displayed on a monitor in real time. A "fishing line" connecting the fish and the rod may be a σ-bond, a van der Waals force, or other weak connections. Here, the molecule/CNT system behaves as a coupled oscillator, where the low-frequency anisotropic vibration of the CNT is transmitted to the molecules via the weak chemical connections that act as an energy filter. Interpretation of the observed motions of the molecules at atomic resolution needs us to consider the quantum mechanical nature of electrons as well as bond rotation, letting us deviate from the conventional statistical world of chemistry. What new horizons can we explore? We have so far carried out conformational studies of individual molecules, assigning anti or gauche conformations to each C-C bond in conformers that we saw. We can also determine the structures of van der Waals assemblies of organic molecules, thereby providing mechanistic insights into crystal formation-phenomena of general significance in science, engineering, and our daily life. Whereas many of the single organic molecules in a vacuum seen by SMART-TEM are sufficiently long-lived for detailed studies, molecules with low ionization potentials (<6 eV) were found to undergo chemical reactions, for example, [60]fullerene and organometallic compounds possibly via a hole catalysis mechanism, where a radical cation of CNT generated under electron irradiation catalyzes the transformation via an electron transfer mechanism. Common organic molecules whose ionization potentials are much higher (>8 eV) than that of CNT (5 eV) remain stable for a time long enough for observation at 60-120 kV acceleration voltage, as they are not oxidized by the CNT radical cation. Alternatively, the reaction may have taken place via an excited state of a molecule produced by energy transfer from CNT possessing excess energy provided by the electron beam. SMART-TEM imaging is a simple approach to the study of the structures ...

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Conformational Analysis of Organic Molecules with Single‐Molecule Atomic‐Resolution Real‐Time Transmission Electron Microscopy ( SMART‐TEM ) Imaging

Harano

Nakamura

2019

Molecular Technology

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Carbon Nanotube for Imaging of Single Molecules in Motion

Cited by 6 publications

References 9 publications

Conformational Analysis of Single Perfluoroalkyl Chains by Single-Molecule Real-Time Transmission Electron Microscopic Imaging

Conformational Analysis of Single Perfluoroalkyl Chains by Single-Molecule Real-Time Transmission Electron Microscopic Imaging

Atomic-Resolution Transmission Electron Microscopic Movies for Study of Organic Molecules, Assemblies, and Reactions: The First 10 Years of Development

Conformational Analysis of Organic Molecules with Single‐Molecule Atomic‐Resolution Real‐Time Transmission Electron Microscopy ( SMART‐TEM ) Imaging

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