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Published on: June 25, 2018
The influence of amine functionalities on anion binding in polyamide-containing macrocycles
Sung Ok Kang1, Victor W Day, Kristin Bowman-James
1Department of Chemistry, University of Kansas, Lawrence, Kansas 66045, USA.
Organic Letters
|July 31, 2009
Summary
New macrocyclic anion hosts selectively bind sulfate over other anions. Their conformation influences anion binding affinity, offering insights for designing advanced anion recognition materials.
Area of Science:
- Supramolecular Chemistry
- Organic Synthesis
- Anion Recognition
Background:
- Macrocyclic compounds are crucial in supramolecular chemistry for selective guest binding.
- Developing hosts for specific anions like sulfate is important for chemical sensing and separation.
Purpose of the Study:
- To synthesize and characterize novel amide/amine macrocyclic anion hosts.
- To investigate the selective binding of these hosts towards various oxo anions and halides.
- To explore the relationship between macrocycle conformation and anion binding affinity.
Main Methods:
- Synthesis and characterization of mixed amide/amine macrocycles.
- Nuclear magnetic resonance (NMR) titrations in DMSO-d(6) to assess binding.
- X-ray crystallography to determine host-anion complex structures.
Main Results:
- Host 2, a 28-membered macrocycle with secondary amines, selectively binds hydrogen sulfate (HSO(4)(-)) over other oxo anions and halides.
- Crystal structures reveal distinct macrocyclic conformations influenced by N-substituents when complexed with sulfate (SO(4)(2-)), hydrogen phosphate (HPO(4)(2-)), dihydrogen phosphate (H(2)PO(4)(-)), and pyrophosphate (H(2)P(2)O(7)(2-)).
- Anion binding affinities correlate with observed macrocycle conformations.
Conclusions:
- The synthesized macrocyclic hosts demonstrate potential for selective anion recognition, particularly for sulfate.
- Macrocyclic conformation is a key determinant of anion binding strength and selectivity.
- These findings provide a foundation for designing tailored macrocyclic hosts for specific anion targets.
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