A second monoclinic polymorph of 3β-chloro-cholest-5-ene
Summary
This study identifies a new crystal form of a C(27)H(45)Cl compound, revealing four unique molecules in its asymmetric unit. This crystal structure exhibits specific molecular conformations and arrangements, differing from previously reported forms.
Area of Science:
- Crystallography
- Solid-state chemistry
- Organic chemistry
Background:
- The title compound, C(27)H(45)Cl, has known crystalline structures.
- Previous reports detail polymorphs crystallizing in the P2(1) space group with fewer unique molecules.
Purpose of the Study:
- To characterize a second monoclinic polymorph of the title compound.
- To describe the crystallographic features and molecular arrangement of this new polymorph.
Main Methods:
- Single-crystal X-ray diffraction analysis.
- Analysis of crystallographic space group and molecular conformations.
- Investigation of intermolecular arrangements in the crystal lattice.
Main Results:
- A second monoclinic polymorph of C(27)H(45)Cl was identified, crystallizing in space group P2(1).
- The asymmetric unit contains four crystallographically independent molecules, a higher number than previously reported.
- Conformations of rings A and C are chair, while rings B and D adopt half-chair forms. Ring junctions B-C and C-D are trans, and A-B is quasi-trans.
- Molecules are arranged in a head-to-tail fashion along the a-axis and stacked along the b-axis.
Conclusions:
- This work expands the understanding of the solid-state behavior of C(27)H(45)Cl by characterizing a novel polymorph.
- The distinct crystallographic features, including the number of independent molecules and their specific conformations, highlight polymorphism in this compound.
- The observed packing arrangement provides insights into intermolecular interactions governing crystal formation.
More Related Videos
13:38Synthesis of Biocompatible Liquid Crystal Elastomer Foams as Cell Scaffolds for 3D Spatial Cell Cultures
Published on: April 11, 2017
09:35Preparation of a Corannulene-functionalized Hexahelicene by Copper(I)-catalyzed Alkyne-azide Cycloaddition of Nonplanar Polyaromatic Units
Published on: September 18, 2016
Related Concept Videos
02:25Molecules with Multiple Chiral Centers
Molecules that possess multiple chiral centers can afford a large number of stereoisomers. For instance, while some molecules like 2-butanol have one chiral center, defined as a tetrahedral carbon atom with four different substituents attached, several molecules like butane-2,3-diol have multiple chiral centers. A simple formula to predict the number of stereoisomers possible for a molecule with n chiral centers is 2n. However, there can be a lower number where some of the stereoisomers are...
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,...
02:05Prochirality
The concept of prochirality leads to the nomenclature of the individual faces of a molecule and plays a crucial role in the enantioselective reaction. It is a concept where two or more achiral molecules react to produce chiral products. A typical process is the reaction of an achiral ketone to generate a chiral alcohol. Here, the achiral reactant reacts with an achiral reducing agent, sodium borohydride, to generate an equimolar mixture of the chiral enantiomers of the product. For example, an...
02:21Naming Enantiomers
The naming of enantiomers employs the Cahn–Ingold–Prelog rules that involve assigning priorities to different substituent groups at a chiral center. Each enantiomer, being a distinct molecule, is assigned a unique name by the Cahn–Ingold–Prelog (CIP) rules, also called the R–S system. The prefix R- or S- attached to the chiral centers in an enantiomer is dependent on the spatial arrangement of the four substituents on the chiral center. The R–S system essentially comprises three steps:...
02:37Disubstituted Cyclohexanes: cis-trans Isomerism
Depending upon the different spatial orientation of the substituents, the disubstituted cycloalkanes exhibit two types of stereoisomers. The cis isomers have the substituents on the same side of the ring, whereas the trans isomers have the substituents on the opposite sides. These stereoisomers exhibit different physical properties and cannot be interconverted without breaking the carbon-carbon bonds.
In cyclohexane, the substituents can occupy different positions generating distinct isomers.
In cyclohexane, the substituents can occupy different positions generating distinct isomers.
02:30Stability of Substituted Cyclohexanes
This lesson discusses the stability of substituted cyclohexanes with a focus on energies of various conformers and the effect of 1,3-diaxial interactions.
The two chair conformations of cyclohexanes undergo rapid interconversion at room temperature. Both forms have identical energies and stabilities, each comprising equal amounts of the equilibrium mixture. Replacing a hydrogen atom with a functional group makes the two conformations energetically non-equivalent.
For example, in...
The two chair conformations of cyclohexanes undergo rapid interconversion at room temperature. Both forms have identical energies and stabilities, each comprising equal amounts of the equilibrium mixture. Replacing a hydrogen atom with a functional group makes the two conformations energetically non-equivalent.
For example, in...