# Synthesis of open-cage ketolactam derivatives of fullerene C60 encapsulating a hydrogen molecule.
> 水素分子を内包するフラーレンC60開口型ケトラクタム誘導体の合成


## Abstract

A new open-cage C60 fullerene derivative bearing a bis(hemiketal) unit was obtained through reaction of C60-N-MEM-ketolactam (MEM: 2-methoxyethoxymethyl) with N-methylmorpholine N-oxide in the presence of water, with the structure confirmed by single-crystal X-ray diffraction. The orifice was subsequently expanded to a 15-membered ring by treatment with trifluoroacetic anhydride, yielding a tetraketo derivative. Exposure of this compound to high-pressure H2 gas allowed encapsulation of a single hydrogen molecule within the cage. Following encapsulation, the opening was contracted back to its original dimensions while retaining the H2 inside. The resulting compound represents a potential precursor for the preparation of endohedral azafullerenes that contain an encapsulated hydrogen molecule.

### Mechanism

High-pressure H2 gas was used to insert a hydrogen molecule through an enlarged 15-membered ring orifice of an open-cage C60 derivative; subsequent chemical reduction of the opening size trapped the H2 molecule inside the fullerene cage.

## Bibliographic

- **Authors**: Hashikawa Y, Murata M, Wakamiya A, Murata Y
- **Journal**: Org Lett
- **Year**: 2014 (2014-06-06)
- **PMID**: [24828793](https://pubmed.ncbi.nlm.nih.gov/24828793/)
- **DOI**: [10.1021/ol501113y](https://doi.org/10.1021/ol501113y)
- **Study type**: other
- **Delivery route**: not specified
- **Effect reported**: not assessed

## Delivery context

The delivery route is not clearly identifiable from this paper. For hydrogen intake, inhalation is the most efficient route; inhalation, however, carries explosion risk (empirical LFL of 10%; high-concentration devices are not recommended).

## Safety notes

The delivery route is not clearly identifiable from this paper. For hydrogen intake, inhalation is the most efficient route; inhalation, however, carries explosion risk (empirical LFL of 10%; high-concentration devices are not recommended).

See also:
- [Inhalation concentration and LFL / UFL](https://h2-papers.org/en/safety-notes/inhalation-concentration)
- [Consumer Affairs Agency accident cases](https://h2-papers.org/en/safety-notes/accident-cases)

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> **Cite as**: H2 Papers — PMID 24828793. https://h2-papers.org/en/papers/24828793
> **Source**: PubMed PMID [24828793](https://pubmed.ncbi.nlm.nih.gov/24828793/)