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Binding Between Cyclohexanohemicucurbit[n]urils and Polar Organic Guests
- Source :
- Frontiers in Chemistry, Vol 9 (2021)
- Publication Year :
- 2021
- Publisher :
- Frontiers Media SA, 2021.
-
Abstract
- Inherently chiral, barrel-shaped, macrocyclic hosts such as cyclohexanohemicucurbit[n]urils (cycHC[n]) bind zinc porphyrins and trifluoroacetic acid externally in halogenated solvents. In the current study, we tested a set of eighteen organic guests with various functional groups and polarity, namely, thiophenols, phenols, and carboxylic and sulfonic acids, to identify a preference toward hydrogen bond–donating molecules for homologous cycHC[6] and cycHC[8]. Guests were characterized by Hirshfeld partial charges on acidic hydrogens and their binding by 1H and 19F NMR titrations. Evaluation of association constants revealed the complexity of the system and indirectly proved an external binding with stoichiometry over 2:1 for both homologs. It was found that overall binding strength is influenced by the stoichiometry of the formed complexes, the partial atomic charge on the hydrogen atom of the hydrogen bond donor, and the bulkiness of the guest. Additionally, a study on the formation of complexes with halogen anions (Cl− and Br−) in methanol and chloroform, analyzed by 1H NMR, did not confirm complexation. The current study widens the scope of potential applications for host molecules by demonstrating the formation of hydrogen-bonded complexes with multisite hydrogen bond acceptors such as cycHC[6] and cycHC[8].
- Subjects :
- hydrogen bond
binding evaluation
Hydrogen bond
Chemistry
Supramolecular chemistry
General Chemistry
Fluorine-19 NMR
Medicinal chemistry
supramolecular chemistry
NMR
Partial charge
chemistry.chemical_compound
Halogen
Proton NMR
Trifluoroacetic acid
hemicucurbit[n]uril
Molecule
complex stoichiometry
QD1-999
Subjects
Details
- ISSN :
- 22962646
- Volume :
- 9
- Database :
- OpenAIRE
- Journal :
- Frontiers in Chemistry
- Accession number :
- edsair.doi.dedup.....b5db7e74bf09269861a5112c545df48e