Related Experiment Video
Updated: May 30, 2026
06:44
From Molecules to Materials: Engineering New Ionic Liquid Crystals Through Halogen Bonding
Published on: March 24, 2018
1-Carb-oxy-methyl-3-octylimidazolium bromide
Nassir N Al-Mohammed1, Yatimah Alias, Zanariah Abdullah
1Department of Chemistry, University of Malaya, 50603 Kuala Lumpur, Malaysia.
Acta Crystallographica. Section E, Structure Reports Online
|August 13, 2011
Summary
This study details the crystal structure of a novel compound, revealing an all-trans octyl chain. Hydrogen bonding interactions between cations and bromide anions form a unique two-dimensional crystal lattice.
Area of Science:
- Crystallography and Molecular Structure
- Supramolecular Chemistry
Background:
- Understanding the packing of organic cations and their counterions is crucial for predicting material properties.
- Hydrogen bonding plays a significant role in directing crystal assembly and stabilizing structures.
Purpose of the Study:
- To elucidate the crystal structure of the title compound, C(13)H(23)N(2)O(2) (+)·Br(-).
- To investigate the role of intermolecular interactions, specifically hydrogen bonding, in the crystal packing.
Main Methods:
- Single-crystal X-ray diffraction analysis was employed to determine the three-dimensional molecular and crystal structure.
- Analysis of interatomic distances and angles to identify and characterize hydrogen bonding interactions (C-H⋯O, C-H⋯Br, O-H⋯Br).
Main Results:
- The octyl chain within the cation adopts an all-trans conformation.
- Cations are organized into zigzag chains along the b axis via C-H⋯O hydrogen bonds.
- Bromide anions bridge these chains through C-H⋯Br interactions, forming a 2D array parallel to the ab plane, with an additional O-H⋯Br interaction observed.
Conclusions:
- The crystal structure is stabilized by a network of hydrogen bonds involving both the organic cation and the bromide anion.
- The observed supramolecular arrangement highlights the importance of weak interactions in dictating the solid-state architecture of ionic compounds.
![Solid-phase Synthesis of [4.4] Spirocyclic Oximes](/_next/image?url=https%3A%2F%2Fcloudfront.jove.com%2FCDNSource%2Fteasers%2F58508.jpg&w=3840&q=50)
Related Concept Videos
02:45Alkyl Halides
Structural Properties
Alkyl halides are halogen-substituted alkanes wherein one or more hydrogen atoms of an alkane is replaced by a halogen atom such as fluorine, chlorine, bromine, or iodine. The carbon atom in an alkyl halide is bonded to the halogen atom, which is sp3-hybridized and exhibits a tetrahedral shape.
Unlike alkyl halides, compounds in which a halogen atom is bonded to an sp2 -hybridized carbon atom of a carbon-carbon double bond (C=C) are called vinyl halides. Whereas aryl...
Alkyl halides are halogen-substituted alkanes wherein one or more hydrogen atoms of an alkane is replaced by a halogen atom such as fluorine, chlorine, bromine, or iodine. The carbon atom in an alkyl halide is bonded to the halogen atom, which is sp3-hybridized and exhibits a tetrahedral shape.
Unlike alkyl halides, compounds in which a halogen atom is bonded to an sp2 -hybridized carbon atom of a carbon-carbon double bond (C=C) are called vinyl halides. Whereas aryl...
02:41Formation of Halohydrin from Alkenes
An alkene, such as propene, reacts with bromine in the presence of water to yield a halohydrin. Halohydrins contain a halogen and a hydroxyl group attached to adjacent carbons. When the halogen is bromine, it is called a bromohydrin, while a chlorohydrin has chlorine as the halogen.
01:28Multiple Halogenation of Methyl Ketones: Haloform Reaction
A method involving the transformation of methyl ketones to carboxylic acids using excess base and halogen is called the haloform reaction. It begins with the deprotonation of α hydrogen to form an enolate ion which reacts with the electrophilic halogen to give an α-halo ketone. The step continues until all the α protons are substituted to form a trihalomethyl ketone. The resulting molecule is unstable, and in the presence of a hydroxide base, it readily undergoes nucleophilic acyl substitution.
02:46Halogenation of Alkenes
Halogenation is the addition of chlorine or bromine across the double bond in an alkene to yield a vicinal dihalide. The reaction occurs in the presence of inert and non-nucleophilic solvents, such as methylene chloride, chloroform, or carbon tetrachloride.
Consider the bromination of cyclopentene. Molecular bromine is polarized in the proximity of the π electrons of cyclopentene. An electrophilic bromine atom adds across the double bond, forming a cyclic bromonium ion intermediate.
Consider the bromination of cyclopentene. Molecular bromine is polarized in the proximity of the π electrons of cyclopentene. An electrophilic bromine atom adds across the double bond, forming a cyclic bromonium ion intermediate.
01:15α-Bromination of Carboxylic Acids: Hell–Volhard–Zelinski Reaction
The method to achieve α-brominated carboxylic acids using a mixture of phosphorus tribromide and bromine is known as the Hell–Volhard–Zelinski reaction. The reaction is catalyzed by phosphorus tribromide, which can be used directly or produced in situ from red phosphorus and bromine. The mechanism comprises PBr3 catalyzed conversion of acid to acid bromide and hydrogen bromide. The acid bromide enolizes to its enol form in the presence of HBr. The nucleophilic enol attacks the bromine molecule...
03:08Hydroboration-Oxidation of Alkenes
In addition to the oxymercuration–demercuration method, which converts the alkenes to alcohols with Markovnikov orientation, a complementary hydroboration-oxidation method yields the anti-Markovnikov product. The hydroboration reaction, discovered in 1959 by H.C. Brown, involves the addition of a B–H bond of borane to an alkene giving an organoborane intermediate. The oxidation of this intermediate with basic hydrogen peroxide forms an alcohol.