Cyclochiral resorcin[4]arenes as effective enantioselectors in the gas phase

J Mass Spectrom. 2012 Jan;47(1):72-8. doi: 10.1002/jms.2028.

Abstract

The effect of cyclochirality of rccc-2,8,14,20-tetra-n-decyl-4,10,16,22-tetra-O-methylresorcin[4]arene (C) on the enantiodiscrimination of a number of chiral bidentate and tridentate aromatic and aliphatic biomolecules (G) has been investigated by nano-electrospray ionization (nano-ESI)-Fourier transform ion cyclotron resonance mass spectrometry. The experimental approach is based on the formation of diastereomeric proton-bound [C·H·G](+) complexes by nano-ESI of solutions containing an equimolar amount of quasi-enantiomers (C) together with the chiral guest (G) and the subsequent measurement of the rate of the G substitution by the attack of several achiral and chiral amines. In general, the heterochiral complexes react faster than the homochiral ones, except when G is an aminoalcoholic neurotransmitter whose complexes, beyond that, exhibit the highest enantioselectivity. The kinetic results were further supported by both collision-induced dissociation experiments on some of the relevant [C(2) ·H·G](+) three-body species and Density functional theory (DFT) calculations performed on the most selective systems.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Calixarenes / chemistry*
  • Fourier Analysis
  • Gases / chemistry
  • Kinetics
  • Macrocyclic Compounds / chemistry
  • Models, Molecular
  • Phenylalanine / analogs & derivatives*
  • Phenylalanine / chemistry
  • Spectrometry, Mass, Electrospray Ionization / methods*
  • Stereoisomerism

Substances

  • Gases
  • Macrocyclic Compounds
  • resorcinarene
  • Calixarenes
  • Phenylalanine