Synthesis, Structure, and Properties of Novel Open‐Cage Fullerenes Having Heteroatom(s) on the Rim of the Orifice

Murata, Yasujiro; Murata, Michihisa; Komatsu, Kôichi

doi:10.1002/chem.200390184

Cited by 156 publications

(171 citation statements)

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“…5 Recently, Murata and co-workers 4,6 have achieved a very high-yield insertion of molecular hydrogen into the azo-thia-open-cage fullerene (H 2 @ATOCF), 4 shown in Figure 1.In this article we describe 1 H NMR measurements on the endohedral H 2 molecules of H 2 @ATOCF in the solid state. We observe a small anisotropy of the H 2 rotation inside the fullerene cage and estimate the correlation time of the H 2 rotation.…”

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confidence: 92%

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Solid-State NMR Spectroscopy of Molecular Hydrogen Trapped Inside an Open-Cage Fullerene

Carravetta

Murata

et al. 2004

J. Am. Chem. Soc.

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The trapping of atoms and molecules [1][2][3][4] inside fullerene cages provides a set of remarkable systems for exploring atomic interactions and molecular dynamics. 5 Recently, Murata and co-workers 4,6 have achieved a very high-yield insertion of molecular hydrogen into the azo-thia-open-cage fullerene (H 2 @ATOCF), 4 shown in Figure 1.In this article we describe 1 H NMR measurements on the endohedral H 2 molecules of H 2 @ATOCF in the solid state. We observe a small anisotropy of the H 2 rotation inside the fullerene cage and estimate the correlation time of the H 2 rotation. These studies complement the low-temperature NMR studies of H 2 molecules trapped in the interstices of solid C 60 . 7 Experimental 1 H spectra for H 2 @ATOCF obtained by magicangle spinning (MAS) solid-state NMR are shown in Figure 2. Figure 2a shows the broad 1 H spectrum in the absence of sample rotation. At a slow MAS frequency, a set of narrow sidebands appears ( Figure 2b). As the spinning frequency is increased ( Figure 2c-d), the sidebands spread out and the centerband grows larger. The narrow centerband has a line width of 0.56 ppm and an isotropic chemical shift of -7.5 ppm with respect to TMS. This unusual shift assigns the narrow peak to the endohedral H 2 and is consistent with solution NMR on the same species. 4 The broad feature is attributed to the relatively immobile exohedral protons and to the proton impurities in the Teflon probe parts. The dipole-dipole couplings involving the endohedral protons are averaged to a large extent by the rapid motion of the H 2 molecule inside the cavity. The residual dipolar couplings are eliminated by the magic-angle rotation, leading to very narrow 1 H signals from the endohedral H 2 . Similar behavior is observed for other solids displaying high molecular mobility. [8][9][10][11] If the rotational motion in the cavity is assumed to be uniaxial, the motionally averaged dipole-dipole between the H 2 nuclei coupling may be written as where S is the second-rank order parameter S ) 〈 (3 cos 2 θ -1)/2〉, and θ is the angle between the HH vector and a molecule-fixed rotational order axis. The angular brackets represent a time or ensemble average. S ) 0 corresponds to isotropic rotation, while S ) 1 corresponds to the static case. The dipoledipole coupling in the absence of motion is where r HH is the proton-proton bond length and γ Η is the proton

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confidence: 92%

“…5 Recently, Murata and co-workers 4,6 have achieved a very high-yield insertion of molecular hydrogen into the azo-thia-open-cage fullerene (H 2 @ATOCF), 4 shown in Figure 1.…”

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confidence: 99%

Solid-State NMR Spectroscopy of Molecular Hydrogen Trapped Inside an Open-Cage Fullerene

Carravetta

Murata

et al. 2004

J. Am. Chem. Soc.

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“…Owing to this discovery, we could obtain a fullerene derivative 3 with sufficiently large opening [4], and molecular hydrogen was found to get inside the open-cage C 60 at 200 • C under a pressure of 800 atmosphere ( figure 1, step d) [5]. Compound 3 is a nanocontainer of a hydrogen molecule, holding hydrogen unless it is heated to temperatures higher than 150 • C.…”

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Molecular surgical synthesis of H ₂ @C ₆₀ : recollections

Komatsu

2013

Phil. Trans. R. Soc. A.

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The first synthesis of endohedral fullerene containing molecular hydrogen, H 2 @C 60 , is briefly summarized. The synthesis was conducted according to what we call the ‘molecular surgical method’, that is, opening a hole on a C 60 surface, enlargement of the hole, insertion of a guest species and enclosure of the hole without loss of the encapsulated guest. The entire process involves three chemical reactions to open the hole and four reactions to gradually reduce the hole size and finally close the hole. The total yield of the product, H 2 @C 60 , based on consumed C 60 was 9%. The encapsulated molecule of hydrogen exhibited a 6 ppm upfield-shifted 1 H NMR signal when compared with free hydrogen, indicating the aromaticity at the inner centre of the C 60 cage.

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“…Murata et al investigated the synthesis, structure, and properties of novel open-cage fullerenes with heteroatom on the rim of the orifice [13] as well as the feasibility of inserting small atoms or molecules through the orifice of an open-cage C 60 derivative. Hatzimarinaki et al reported a novel methodology for the preparation of five-, seven-, and nine-membered fused rings on C 60 fullerene [14].…”

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“…Recently, molecular hydrogen was successfully placed inside open-cage fullerenes [13,[15][16][17][18][19][20][21]. Murata et al [16] reported the first syntheses and X-ray structures of organic and organometallic derivatives of C 60 and the usage of the encapsulated molecular hydrogen as a magnetic shielding probe.…”

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confidence: 99%

Hydrogen Adsorption and Penetration of Cx (x=58-62) Fullerenes with Defects

Yue

Zhao

Qiu

2007

Computational Science – ICCS 2007

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Abstract. Density functional theory calculations were performed to investigate the endohedral and exohedral adsorption of a H 2 molecule on the classical and nonclassical fullerenes C x (x=58, 59, 60, 62) with seven-, eight-, and ninemembered rings. The amplitude of adsorption energies are within 0.03eV and the molecule-fullerene interaction belongs to van der Waals type. Penetration of a H 2 molecule through different fullerene cages was discussed and the corresponding energy barriers were obtained. We find that the existence of large holes reduces the penetration barrier from 12.6 eV for six-membered ring on perfect C 60 cage to about 8eV for seven-membered rings and to about 5eV for eight-membered rings.

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Synthesis, Structure, and Properties of Novel Open‐Cage Fullerenes Having Heteroatom(s) on the Rim of the Orifice

Cited by 156 publications

References 60 publications

Solid-State NMR Spectroscopy of Molecular Hydrogen Trapped Inside an Open-Cage Fullerene

Solid-State NMR Spectroscopy of Molecular Hydrogen Trapped Inside an Open-Cage Fullerene

Molecular surgical synthesis of H ₂ @C ₆₀ : recollections

Hydrogen Adsorption and Penetration of Cx (x=58-62) Fullerenes with Defects

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Synthesis, Structure, and Properties of Novel Open‐Cage Fullerenes Having Heteroatom(s) on the Rim of the Orifice

Cited by 156 publications

References 60 publications

Solid-State NMR Spectroscopy of Molecular Hydrogen Trapped Inside an Open-Cage Fullerene

Solid-State NMR Spectroscopy of Molecular Hydrogen Trapped Inside an Open-Cage Fullerene

Molecular surgical synthesis of H 2 @C 60 : recollections

Hydrogen Adsorption and Penetration of Cx (x=58-62) Fullerenes with Defects

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Molecular surgical synthesis of H ₂ @C ₆₀ : recollections