# Alkynylcyclohexanol chairs and twist-boats: Co(2)(CO)(6) as a conformational switch.
> アルキニルシクロヘキサノールの椅子型・ツイストボート型配座：Co₂(CO)₆による配座制御


## Abstract

This study examines how complexation with dicobalt octacarbonyl influences the ring conformation of alkynylcyclohexanol derivatives. When the bulky cobalt-alkyne cluster forms on an axially positioned ethynyl group, a conformational ring flip occurs to place the cluster in the equatorial position. A 4-tert-butyl substituent prevents this inversion, locking the coordinated alkynyl group in its original orientation. For the trans-diaxial diol, complexation drives a chair-to-chair inversion placing both cluster units equatorially. The cis-diol isomers instead adopt twist-boat conformations: one exhibiting intramolecular hydrogen bonding between hydroxyl groups, the other forming intermolecular hydrogen-bonded networks depending on the silyl substituent. Eight cobalt cluster complexes were structurally confirmed by X-ray crystallography, and the synthetic utility of twist-boat conformers is discussed.

### Mechanism

The steric bulk of the dicobalt-alkyne cluster drives equatorial preference in cyclohexane ring conformations; cis-diol substrates instead adopt twist-boat geometries that facilitate intramolecular or intermolecular hydrogen bonding between hydroxyl groups.

## Bibliographic

- **Authors**: Deschamps NM, Kaldis JH, Lock PE, Britten JF, McGlinchey MJ
- **Journal**: J Org Chem
- **Year**: 2001 (2001-12-14)
- **PMID**: [11735541](https://pubmed.ncbi.nlm.nih.gov/11735541/)
- **DOI**: [10.1021/jo0108820](https://doi.org/10.1021/jo0108820)
- **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 11735541. https://h2-papers.org/en/papers/11735541
> **Source**: PubMed PMID [11735541](https://pubmed.ncbi.nlm.nih.gov/11735541/)