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
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.
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.
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:
https://h2-papers.org/en/papers/11735541