A single <i>but</i> hydrogen-bonded water molecule confined in an anisotropic subnanospace

Hashikawa, Yoshifumi; Hasegawa, Shota; Murata, Yasujiro

doi:10.1039/c8cc07339b

“…Communications 320 K. To avoid the dimerization of NO@3, the sample concentration was set to 1.0 mM in which the NO@3/ (NO@3) 2 ratio is predicted to be 98:2 from the association constant. [13] The chemical shifts of diamagnetic 3 were temperature-independent at this concentration ( Figure S5). As shown in Figure 4 a, the methine protons highlighted with red, green, and blue showed large paramagnetic shifts at 260 K when compared with those in a reference (3).…”

Section: Angewandte Chemiementioning

confidence: 94%

Precise Fixation of an NO Molecule inside Carbon Nanopores: A Long‐Range Electron–Nuclear Interaction

Hashikawa

¹

,

Hasegawa

²

,

Murata

³

2020

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[60]Fullerene‐based carbon nanopores were synthesized to enable the placement of two molecules of nitric oxide (NO) at an accurate distance from one another. A linear orientation of the two NO molecules inside the assembled nanopores was confirmed crystallographically. Theoretical studies suggested possible free rotation inside the carbon nanopore, while the two conformations of NO in which its long axis was oriented toward the orifice of the nanopore were predicted to be dominant. The paramagnetic shifts caused by NO showed a major contribution from the Fermi contact mechanism. The Solomon–Bloembergen theory was found to describe well the paramagnetic relaxation enhancement of a water molecule in a paired nanopore even under equilibrium as a result of fixing of the NO molecule with a distance of approximately 12 Å, thus demonstrating a long‐range bimolecular magnetic interaction.

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“…At this concentration, a monomer/dimer ratio is expected to be 77:23. [13] Considering the association constant and composition ratio, the H 2 Oadsorbed species are constituted of H 2 O@3, (H 2 O@3) 2 , (H 2 O@3)•(3), and (H 2 O@3)•(NO@3) with a ratio of 14:5:35:46 as being in a state of dynamic equilibrium.…”

Section: Angewandte Chemiementioning

confidence: 99%

Precise Fixation of an NO Molecule inside Carbon Nanopores: A Long‐Range Electron–Nuclear Interaction

Hashikawa

¹

,

Hasegawa

²

,

Murata

³

2020

Self Cite

View full text Add to dashboard Cite

[60]Fullerene‐based carbon nanopores were synthesized to enable the placement of two molecules of nitric oxide (NO) at an accurate distance from one another. A linear orientation of the two NO molecules inside the assembled nanopores was confirmed crystallographically. Theoretical studies suggested possible free rotation inside the carbon nanopore, while the two conformations of NO in which its long axis was oriented toward the orifice of the nanopore were predicted to be dominant. The paramagnetic shifts caused by NO showed a major contribution from the Fermi contact mechanism. The Solomon–Bloembergen theory was found to describe well the paramagnetic relaxation enhancement of a water molecule in a paired nanopore even under equilibrium as a result of fixing of the NO molecule with a distance of approximately 12 Å, thus demonstrating a long‐range bimolecular magnetic interaction.

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“…The notation indicates the modified exit ridge. NO@C60-OH1 (Hasegawa et al, 2018a) and NO@C60-OH3 were prepared by following the literature (Hasegawa et al, 2018a) and the modified procedures are described in references (Hasegawa et al, 2018a;Hashikawa et al, 2018)]. DFT optimized structures of a) NO@C60-OH1, and b) NO@C60-OH3.…”

Section: Sample Preparationmentioning

confidence: 99%

“…In a series of recent publications, the Kyoto group has shown that it is possible to encapsulate small and even reactive molecules in a modified C 60 cage with tailored entrance and exit holes (Hasegawa et al, 2018a;Futagoishi et al, 2017;Hashikawa et al, 2018). Using such designer type open cages instead of closed structures creates a new route for the preparation of interesting compounds.…”

Section: Introductionmentioning

confidence: 99%

EPR Study of NO radicals encased in modified open C60 Fullerenes

Dinse¹,

Kato²,

Hasegawa³

et al. 2020

Preprint

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Abstract. Using pulsed EPR techniques, the low temperature magnetic properties of the NO radical being confined in a C60 derived cage are determined. It is found that the smallest principal g value g3, being assigned to the axis of the radical, deviates strongly from the free electron value. This behavior results from partial compensation of the spin and orbital contributions to the g3 value. The measured value g3 = 0.77(5) yields information about the deviation of the locking potential from axial symmetry. This 17 meV asymmetry is found to be quite small compared to the situation found for the same radical in polycrystalline or amorphous matrices ranging from 300 to 500 meV. The analysis of the temperature dependence of spin relaxation times resulted in a critical temperature of about 3.5 K, assigned to temperature activated motion of the radical with coupled rotational and translational degrees of freedom in the complicated 3-dimensional potential.

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A single but hydrogen-bonded water molecule confined in an anisotropic subnanospace

Abstract: A single but H-bonded H2O was realized within an anisotropic subnanospace using an open-cage C60 derivative having hydroxy groups on the opening.

Cited by 45 publications

References 34 publications

Precise Fixation of an NO Molecule inside Carbon Nanopores: A Long‐Range Electron–Nuclear Interaction

Precise Fixation of an NO Molecule inside Carbon Nanopores: A Long‐Range Electron–Nuclear Interaction

Precise Fixation of an NO Molecule inside Carbon Nanopores: A Long‐Range Electron–Nuclear Interaction

EPR Study of NO radicals encased in modified open C60 Fullerenes

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