Related Experiment Video
Updated: Jul 27, 2025
06:44
From Molecules to Materials: Engineering New Ionic Liquid Crystals Through Halogen Bonding
Published on: March 24, 2018
69.1K
Squaramide-Based Heteroditopic [2]Rotaxanes for Sodium Halide Ion-Pair Recognition
Arya Arun1, Andrew Docker1, Hui Min Tay1
1Department of Chemistry, University of Oxford, Chemistry Research Laboratory, Mansfield Road, OX1 3TA, Oxford, UK.
Chemistry (Weinheim an Der Bergstrasse, Germany)
|June 10, 2023
Summary
New [2]rotaxanes use sodium ions to form mechanically interlocked molecules. These squaramide-based hosts exhibit strong cooperative recognition of sodium halide ion pairs, enabling salt extraction into organic solvents.
Area of Science:
- Supramolecular Chemistry
- Organic Synthesis
- Host-Guest Chemistry
Background:
- Rotaxanes are mechanically interlocked molecules with potential applications in molecular machines and sensing.
- Squaramide motifs are known for their hydrogen bonding capabilities and anion recognition properties.
Purpose of the Study:
- To synthesize novel squaramide-based heteroditopic [2]rotaxanes.
- To investigate the ion-pair recognition capabilities of these rotaxanes with alkali metal halides.
- To explore the use of these rotaxanes for the extraction of salts.
Main Methods:
- Synthesis of [2]rotaxanes using alkali metal cation template-directed methodology.
- 1H NMR spectroscopy for anion and ion-pair recognition studies.
- Solvent extraction experiments to demonstrate salt binding.
Main Results:
- Successful synthesis of squaramide-based heteroditopic [2]rotaxanes templated by sodium cations.
- Demonstrated cooperative recognition of sodium halide ion pairs, with up to 20-fold enhancement for bromide and iodide.
- Identification of ambidentate binding sites within the squaramide axle for simultaneous cation and anion interaction.
- Tuning of ion-pair binding affinities by modifying the macrocycle's polyether cation binding unit.
- Successful extraction of solid sodium halide salts into organic media.
Conclusions:
- Squaramide-based heteroditopic [2]rotaxanes are effective hosts for sodium halide ion pairs.
- The unique ambidentate binding sites enable cooperative recognition and salt extraction.
- This work expands the design principles for functional rotaxanes in supramolecular chemistry.
More Related Videos
Related Concept Videos
01:20Diazonium Group Substitution with Halogens and Cyanide: Sandmeyer and Schiemann Reactions
1.9K
Arenediazonium substitution reactions occur when the diazonium group is substituted by various functional groups such as halides, hydroxyl, nitrile, etc. For instance, arenediazonium salts react with copper(I) salts of chloride, bromide, or cyanide to form corresponding aryl chlorides, bromides, and nitriles. These reactions are named Sandmeyer reactions. Although the mechanism of this reaction is complicated, as illustrated in Figure 1, they are believed to progress via an aryl copper...
1.9K
02:38Electrophilic Addition to Alkynes: Halogenation
8.3K
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.
8.3K
02:30Chirality at Nitrogen, Phosphorus, and Sulfur
5.8K
Chirality is most prevalent in carbon-based tetrahedral compounds, but this important facet of molecular symmetry extends to sp3-hybridized nitrogen, phosphorus and sulfur centers, including trivalent molecules with lone pairs. Here, the lone pair behaves as a functional group in addition to the other three substituents to form an analogous tetrahedral center that can be chiral.
A consequence of chirality is the need for enantiomeric resolution. While this is theoretically possible for all...
A consequence of chirality is the need for enantiomeric resolution. While this is theoretically possible for all...
5.8K
02:45Alkyl Halides
16.9K
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...
16.9K
02:26Preparation and Reactions of Sulfides
5.0K
Sulfides are the sulfur analog of ethers, just as thiols are the sulfur analog of alcohol. Like ethers, sulfides also consist of two hydrocarbon groups bonded to the central sulfur atom. Depending upon the type of groups present, sulfides can be symmetrical or asymmetrical. Symmetrical sulfides can be prepared via an SN2 reaction between 2 equivalents of an alkyl halide and one equivalent of sodium sulfide.
5.0K
02:46Halogenation of Alkenes
15.8K
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.
15.8K