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Updated: Aug 16, 2026

Photoelectron Imaging of Anions Illustrated by 310 Nm Detachment of F−
Published on: July 27, 2018
Fomenting proton anisochronicity in the CH2D group
Benjamin D Allen1, Daniel J O'Leary
1Department of Chemistry, Pomona College, 645 North College Avenue, Claremont, CA 91711-6338, USA.
Abstract:
A novel C-D...N interaction promotes an equilibrium isotope effect that causes a large chemical shift difference (43 ppb, 22 degrees C) for the diastereotopic methyl protons in the (N-CH2D)-(-)-isosparteinium cation. The observed chemical shift difference is in surprising agreement with a prediction of 44 ppb based upon an ab initio protocol. These calculations are also shown to reproduce the experimental shift difference in Anet's alpha-deutero-1,2-dimethylpiperidine (theory, 17 ppb; experiment, 14 ppb). The isosparteine-derived system described herein may provide an improved method for assigning the configuration and enantiomeric purity of stereogenic methyl groups (R-CHDT) by tritium NMR spectroscopy.
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