Related Experiment Video
Updated: May 31, 2026
10:52
Line Shape Analysis of Dynamic NMR Spectra for Characterizing Coordination Sphere Rearrangements at a Chiral Rhenium Polyhydride Complex
Published on: July 27, 2022
Redetermined structure, inter-molecular inter-actions and absolute configuration of royleanone
Summary
The crystal structure of a specific diterpenoid (C(20)H(28)O(3)) was confirmed and its molecular packing detailed. Researchers determined its absolute configuration and conformational preferences, revealing intricate hydrogen bonding and crystal interactions.
Area of Science:
- Organic Chemistry
- Crystallography
- Chemical Physics
Background:
- Diterpenoids are a class of naturally occurring compounds with diverse biological activities.
- Understanding the precise three-dimensional structure of organic molecules is crucial for structure-activity relationship studies.
- Accurate structural determination aids in predicting and explaining chemical and physical properties.
Purpose of the Study:
- To confirm the established structure of the title diterpenoid, C(20)H(28)O(3).
- To describe the crystal packing and intermolecular interactions of this diterpenoid.
- To elucidate the absolute structure and conformational analysis of the molecule in the solid state.
Main Methods:
- Single-crystal X-ray diffraction using Cu radiation.
- Refinement of crystallographic data to determine atomic positions and bonding.
- Analysis of molecular conformation, including ring conformations and hydrogen bonding.
Main Results:
- The absolute structure of the diterpenoid was confirmed, with both stereogenic centers possessing S configurations.
- Detailed description of the crystal packing, including intermolecular O-H⋯O hydrogen bonds forming chains along the [010] direction.
- Identification of an intramolecular O-H⋯O hydrogen bond creating an S(5) ring motif and weak C-H⋯O interactions.
Conclusions:
- The study provides a comprehensive understanding of the solid-state structure and packing of the title diterpenoid.
- The conformational analysis reveals specific arrangements of the cyclohexene rings and the benzoquinone moiety.
- The identified hydrogen bonding patterns contribute to the overall crystal architecture and molecular stability.
Related Concept Videos
01:28Structures of Carboxylic Acid Derivatives
Structure of Carboxylic Acid Derivatives
Carboxylic acid derivatives contain an acyl group attached to a heteroatom such as chlorine, oxygen, or nitrogen. The carbonyl carbon and oxygen are both sp2-hybridized with an unhybridized p orbital.
The three sp2 orbitals of the carbonyl carbon form three σ bonds, one each with the carbonyl oxygen, the α carbon, and the heteroatom, whereas the other two sp2 orbitals of the carbonyl oxygen are occupied by the lone pairs. Further, the unhybridized p...
Carboxylic acid derivatives contain an acyl group attached to a heteroatom such as chlorine, oxygen, or nitrogen. The carbonyl carbon and oxygen are both sp2-hybridized with an unhybridized p orbital.
The three sp2 orbitals of the carbonyl carbon form three σ bonds, one each with the carbonyl oxygen, the α carbon, and the heteroatom, whereas the other two sp2 orbitals of the carbonyl oxygen are occupied by the lone pairs. Further, the unhybridized p...
02:33Stereoisomerism of Cyclic Compounds
In this lesson, we delve into the role of ring conformation and its stability, which determines the spatial arrangement and, consequently, the molecular symmetry and stereoisomerism of cyclic compounds. 1,2-Dimethylcyclohexane is used as a case study to evaluate the possible number of stereoisomers. Here, given the multiple (n = 2) chiral centers, there are 2n = 4 possible configurations that lack a plane of symmetry, as the ring skeleton exists in a non-planar chair conformation. In addition,...
01:04Structures of Aldehydes and Ketones
Vanillin—a flavoring agent in vanilla, cinnamaldehyde—a molecule responsible for the distinct smell of cinnamon, and acetone—a strong-smelling ingredient in nail polish removers, all belong to a class of carbonyl compounds called aldehydes and ketones (Figure 1). Although both aldehydes and ketones contain the characteristic carbonyl (C=O) bond, their chemical structures vary with respect to the groups directly attached to the carbonyl carbon.
In aldehydes (Figures 1a and 1b), the carbonyl...
In aldehydes (Figures 1a and 1b), the carbonyl...
02:02Chair Conformation of Cyclohexane
The chair conformation is the most stable form of cyclohexane due to the absence of angle and torsional strain. The absence of angle strain is a result of cyclohexane’s bond angle being very close to the ideal tetrahedral bond angle of 109.5° in its chair conformer. Similarly, the torsional strain is also absent owing to the perfectly staggered arrangement of bonds.
The hydrogen atoms linked to carbons are arranged in two different axial and equatorial orientations to achieve this staggered...
The hydrogen atoms linked to carbons are arranged in two different axial and equatorial orientations to achieve this staggered...
01:34Woodward–Hoffmann Selection Rules and Microscopic Reversibility
Electrocyclic reactions, cycloadditions, and sigmatropic rearrangements are concerted pericyclic reactions that proceed via a cyclic transition state. These reactions are stereospecific and regioselective. The stereochemistry of the products depends on the symmetry characteristics of the interacting orbitals and the reaction conditions. Accordingly, pericyclic reactions are classified as either symmetry-allowed or symmetry-forbidden. Woodward and Hoffmann presented the selection criteria for...
02:16Resonance and Hybrid Structures
According to the theory of resonance, if two or more Lewis structures with the same arrangement of atoms can be written for a molecule, ion, or radical, the actual distribution of electrons is an average of that shown by the various Lewis structures.
Resonance Structures and Resonance Hybrids
The Lewis structure of a nitrite anion (NO2−) may actually be drawn in two different ways, distinguished by the locations of the N–O and N=O bonds.
Resonance Structures and Resonance Hybrids
The Lewis structure of a nitrite anion (NO2−) may actually be drawn in two different ways, distinguished by the locations of the N–O and N=O bonds.