Next Article in Journal
A Novel Sucrose-Regulatory MADS-Box Transcription Factor GmNMHC5 Promotes Root Development and Nodulation in Soybean (Glycine max [L.] Merr.)
Next Article in Special Issue
Simultaneous Disulfide and Boronic Acid Ester Exchange in Dynamic Combinatorial Libraries
Previous Article in Journal
Quantum Chemical and Kinetic Study on Polychlorinated Naphthalene Formation from 3-Chlorophenol Precursor
Previous Article in Special Issue
Supracolloidal Assemblies as Sacrificial Templates for Porous Silk-Based Biomaterials
Article Menu
Issue 9 (September) cover image

Export Article

Open AccessArticle
Int. J. Mol. Sci. 2015, 16(9), 20641-20656; doi:10.3390/ijms160920641

NMR Studies on Li+, Na+ and K+ Complexes of Orthoester Cryptand o-Me2-1.1.1

Department of Chemistry and Pharmacy, Friedrich-Alexander University Erlangen-Nürnberg (FAU), Henkestr. 42, 91054 Erlangen, Germany
*
Author to whom correspondence should be addressed.
Academic Editor: John Hardy
Received: 10 July 2015 / Revised: 6 August 2015 / Accepted: 24 August 2015 / Published: 31 August 2015
(This article belongs to the Special Issue Supramolecular Interactions)
View Full-Text   |   Download PDF [2370 KB, uploaded 31 August 2015]   |  

Abstract

Cryptands, a class of three-dimensional macrobicyclic hosts ideally suited for accommodating small guest ions, have played an important role in the early development of supramolecular chemistry. In contrast to related two-dimensional crown ethers, cryptands have so far only found limited applications, owing in large part to their relatively inefficient multistep synthesis. We have recently described a convenient one-pot, template synthesis of cryptands based on O,O,O-orthoesters acting as bridgeheads. Here we report variable-temperature, 1H-1D EXSY and titration NMR studies on lithium, sodium, and potassium complexes of one such cryptand (o-Me2-1.1.1). Our results indicate that lithium and sodium ions fit into the central cavity of the cryptand, resulting in a comparably high binding affinity and slow exchange with the bulk. The potassium ion binds instead in an exo fashion, resulting in relatively weak binding, associated with fast exchange kinetics. Collectively, these results indicate that orthoester cryptands such as o-Me2-1.1.1 exhibit thermodynamic and kinetic properties in between those typically found for classical crown ethers and cryptands and that future efforts should be directed towards increasing the binding constants. View Full-Text
Keywords: supramolecular chemistry; cryptands; orthoesters; dynamic covalent chemistry; NMR spectroscopy; host-guest complexes supramolecular chemistry; cryptands; orthoesters; dynamic covalent chemistry; NMR spectroscopy; host-guest complexes
Figures

This is an open access article distributed under the Creative Commons Attribution License which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. (CC BY 4.0).

Supplementary material

Scifeed alert for new publications

Never miss any articles matching your research from any publisher
  • Get alerts for new papers matching your research
  • Find out the new papers from selected authors
  • Updated daily for 49'000+ journals and 6000+ publishers
  • Define your Scifeed now

SciFeed Share & Cite This Article

MDPI and ACS Style

Brachvogel, R.-C.; Maid, H.; von Delius, M. NMR Studies on Li+, Na+ and K+ Complexes of Orthoester Cryptand o-Me2-1.1.1. Int. J. Mol. Sci. 2015, 16, 20641-20656.

Show more citation formats Show less citations formats

Related Articles

Article Metrics

Article Access Statistics

1

Comments

[Return to top]
Int. J. Mol. Sci. EISSN 1422-0067 Published by MDPI AG, Basel, Switzerland RSS E-Mail Table of Contents Alert
Back to Top