(−)-β-Caryophyllene (compound 6) was structurally analyzed using cage 1a and phenanthrene (2a) in the size-compensation strategy for low-polarity small molecules.
G076 · Sesquiterpenoid
(−)-β-Caryophyllene
C15H24 · 204.36 g mol−1
First crystal structure · Reported for the unmodified analyte in this study → · Read the story ↓
INTERACTIVE 3D STRUCTURE
Explore (−)-β-Caryophyllene in its crystalline sponge
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CHONCagePhenanthrene 2a
- Molecular formula
- C15H24
- Molecular weight
- 204.36 g mol−1
- CCDC accession
- 2565728 ↗
- Host
- Pd6L4 cage 1a
- Compound in publication
- 6
MOLECULAR HISTORY
From optical rotations to the unmodified hydrocarbon
Caryophyllene’s handedness was established long before the present experiment. Early researchers worked through chemically related derivatives, and crystallography later confirmed that assignment in an iodine-containing product. The 2026 structure records the unmodified hydrocarbon inside the cage.
- 1954
Handedness from molecular rotations
Barton and Nickon deduced caryophyllene’s absolute configuration from molecular rotations of tricyclic derivatives whose relative stereochemistry was already known. Their analysis linked optical behaviour to molecular handedness through a carefully established network of chemical relationships.1
- 1968
A derivative provides X-ray confirmation
Hawley, Ferguson and Robertson determined the structure and absolute stereochemistry of caryophyllene iodonitrosite. They explicitly reported that the X-ray result confirmed the earlier assignment for caryophyllene, although the crystal contained a chemically modified derivative.2
- 2026
A crystal structure without derivatization
The hydrocarbon itself is finally resolved in the host crystal, with phenanthrene filling the remaining cavity space. The published study reports the first crystal structure of unmodified (−)-β-caryophyllene, then uses chiral cage 1b to strengthen absolute-configuration assignment for the same guest.3
WHY THIS STRUCTURE MATTERS
This structure adds a direct view of the unchanged hydrocarbon to a well-established stereochemical history. It is the native analyte, rather than the previously crystallized iodonitrosite derivative, that is resolved in the host cavity.
References
- D. H. R. Barton; A. Nickon. “Sesquiterpenoids. Part VI. The absolute configuration of caryophyllene.” J. Chem. Soc. 1954, 4665–4669. DOI 10.1039/JR9540004665 ↗
- D. M. Hawley; G. Ferguson; J. M. Robertson. “Caryophyllene rearrangement products. Part I. The crystal structure and absolute stereochemistry of caryophyllene “iodonitrosite”, a stable nitroxide radical.” J. Chem. Soc. B 1968, 1255–1261. DOI 10.1039/J29680001255 ↗
- W. He; L. Soliman; H. Takezawa; M. Fujita. “Expanding the Chemical Space of Analytes in the 2G Crystalline Sponge Method: Size-Compensation Strategy for the Structural Analysis of Low-Polarity Small Molecules.” Angew. Chem. Int. Ed. 2026, e4748505. DOI 10.1002/anie.4748505 ↗
Crystal records in this study
| Host | Modulator | CCDC | SI table |
|---|---|---|---|
| Standard cage 1a | Phenanthrene 2a | 2565728 | S3 |
SOURCE PUBLICATION
Expanding the Chemical Space of Analytes in the 2G Crystalline Sponge Method: Size-Compensation Strategy for the Structural Analysis of Low-Polarity Small Molecules
W. He, L. Soliman, H. Takezawa, M. Fujita
Angew. Chem. Int. Ed. 2026, e4748505.
First published: 20 October 2026 · Early View
DOI 10.1002/anie.4748505 ↗Enhanced absolute-configuration determination
The known absolute configuration of the chiral diamine ligand at each Pd center of the cage serves as an internal stereochemical reference for comparison with the guest. Introducing chirality into the host framework also improves absolute-structure discrimination by anomalous scattering, as assessed by the Flack parameter below.
Chiral cage 1b · CCDC 2565759 ↗
Flack x = 0.026(5) (Parsons; CIF)
