Related Experiment Video
Updated: Jun 22, 2026
06:44
From Molecules to Materials: Engineering New Ionic Liquid Crystals Through Halogen Bonding
Published on: March 24, 2018
A facile route to C2-substituted imidazolium ionic liquids
1Department of Chemistry, Middle Tennessee State University, Murfreesboro, TN 37132, USA.
Molecules (Basel, Switzerland)
|June 26, 2009
Summary
Researchers developed a new method for creating C2-substituted imidazolium ionic liquids. This efficient route involves alkylating N-heterocyclic carbenes derived from readily available precursors.
Area of Science:
- Organic Chemistry
- Materials Science
Background:
- Imidazolium ionic liquids are versatile compounds with applications in various fields.
- Functionalization at the C2 position of imidazolium rings is crucial for tuning their properties.
Purpose of the Study:
- To report a convenient and efficient synthetic route for C2-substituted imidazolium ionic liquids.
- To explore the scope and limitations of the developed method.
Main Methods:
- Generation of N-heterocyclic carbenes from C2-unsubstituted imidazolium ionic liquids.
- Alkylation of N-heterocyclic carbenes using alkyl chlorides.
- Anion metathesis to yield the final ionic liquids.
Main Results:
- The method is effective for non-functionalized alkyl chlorides.
- Reactions with alkyl bromides and iodides show lower yields, potentially due to elimination reactions.
- C2-substituted salts are successfully converted to ionic liquids.
Conclusions:
- A practical synthetic strategy for C2-substituted imidazolium ionic liquids has been established.
- The choice of alkyl halide impacts the reaction efficiency.
- This method provides access to a range of functionalized imidazolium ionic liquids.
More Related Videos
Related Concept Videos
01:14Nucleophilic Aromatic Substitution of Aryldiazonium Salts: Aromatic SN1
Treating arylamines with nitrous acid gives aryldiazonium salts that are effective substrates in nucleophilic aromatic substitution reactions. The diazonio group in these salts can be easily displaced by different nucleophiles, yielding a wide variety of substituted benzenes. The leaving group departs as nitrogen gas, and this easy elimination is the driving force for the substitution reaction.
In the Sandmeyer reaction, for example, the diazonio group is replaced by a chloro, bromo, or cyano...
In the Sandmeyer reaction, for example, the diazonio group is replaced by a chloro, bromo, or cyano...
01:14Electrophilic 1,2- and 1,4-Addition of X2 to 1,3-Butadiene
Electrophilic addition of halogens to alkenes proceeds via a cyclic halonium ion to form a 1,2-dihalide or a vicinal dihalide.
01:25Basicity of Heterocyclic Aromatic Amines
Heterocyclic amines, where the N atom is a part of an alicyclic system, are similar in basicity to alkylamines. Interestingly, the heterocyclic amine having a nitrogen atom as part of an aromatic ring has much less basicity than its corresponding alicyclic counterpart. For this reason, as presented in Figure 1, piperidine (pKb = 2.8) is significantly more basic than pyridine (pKb = 8.8).
01:13Electrophilic Aromatic Substitution: Fluorination and Iodination of Benzene
Bromination and chlorination of aromatic rings by electrophilic aromatic substitution reactions are easily achieved, but fluorination and iodination are difficult to achieve. Fluorine is so reactive that its reaction with benzene is difficult to control, resulting in poor yields of monofluoroaromatic products. To address this, Selectfluor reagent is used as a fluorine source in which a fluorine atom is bonded to a positively charged nitrogen.
01:16Cycloaddition Reactions: Overview
Cycloadditions are one of the most valuable and effective synthesis routes to form cyclic compounds. These are concerted pericyclic reactions between two unsaturated compounds resulting in a cyclic product with two new σ bonds formed at the expense of π bonds. The [4 + 2] cycloaddition, known as the Diels–Alder reaction, is the most common. The other example is a [2 + 2] cycloaddition.
02:38Electrophilic Addition to Alkynes: Halogenation
Introduction
Halogenation is another class of electrophilic addition reactions where a halogen molecule gets added across a π bond. In alkynes, the presence of two π bonds allows for the addition of two equivalents of halogens (bromine or chlorine). The addition of the first halogen molecule forms a trans-dihaloalkene as the major product and the cis isomer as the minor product. Subsequent addition of the second equivalent yields the tetrahalide.
Halogenation is another class of electrophilic addition reactions where a halogen molecule gets added across a π bond. In alkynes, the presence of two π bonds allows for the addition of two equivalents of halogens (bromine or chlorine). The addition of the first halogen molecule forms a trans-dihaloalkene as the major product and the cis isomer as the minor product. Subsequent addition of the second equivalent yields the tetrahalide.