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Enantioselective Recognition of Racemic Amino Alcohols in Aqueous Solution by Chiral Metal‐Oxide Keplerate {Mo 132 } Cluster Capsules
Author(s) -
Pow Robert W.,
Sinclair Zoё L.,
Bell Nicola L.,
Watfa Nancy,
AbulHaija Yousef M.,
Long DeLiang,
Cronin Leroy
Publication year - 2021
Publication title -
chemistry – a european journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.687
H-Index - 242
eISSN - 1521-3765
pISSN - 0947-6539
DOI - 10.1002/chem.202100899
Subject(s) - enantiomer , polyoxometalate , chemistry , enantioselective synthesis , aqueous solution , molecule , chirality (physics) , reagent , nuclear magnetic resonance spectroscopy , chiral derivatizing agent , solvent , combinatorial chemistry , stereochemistry , organic chemistry , catalysis , chiral column chromatography , chiral symmetry , physics , quantum mechanics , nambu–jona lasinio model , quark
Determining the relative configuration or enantiomeric excess of a substance may be achieved using NMR spectroscopy by employing chiral shift reagents (CSRs). Such reagents interact noncovalently with the chiral solute, resulting in each chiral form experiencing different magnetic anisotropy; this is then reflected in their NMR spectra. The Keplerate polyoxometalate (POM) is a molybdenum‐based, water‐soluble, discrete inorganic structure with a pore‐accessible inner cavity, decorated by differentiable ligands. Through ligand exchange from the self‐assembled nanostructure, a set of chiral Keplerate host molecules has been synthesised. By exploiting the interactions of analyte molecules at the surface pores, the relative configuration of chiral amino alcohol guests (phenylalaninol and 2‐amino‐1‐phenylethanol) in aqueous solvent was establish and their enantiomeric excess was determined by 1 H NMR using shifts of ΔΔ δ =0.06 ppm. The use of POMs as chiral shift reagents represents an application of a class that is yet to be well established and opens avenues into aqueous host‐guest chemistry with self‐assembled recognition agents.