Related Experiment Video
Updated: Jul 20, 2026

Line Shape Analysis of Dynamic NMR Spectra for Characterizing Coordination Sphere Rearrangements at a Chiral Rhenium Polyhydride Complex
Published on: July 27, 2022
Computation of through-space NMR shielding effects by aromatic ring-cation complexes: substantial synergistic effect
Ned H Martin1, Kristin L Main, Amy K Pyles
1Department of Chemistry and Biochemistry, University of North Carolina Wilmington, 601 S. College Road, Wilmington, NC 28403-5932, USA. martinn@uncw.edu
Abstract:
The HF-GIAO method in Gaussian 03 was employed to calculate the NMR isotropic shielding values of a diatomic hydrogen probe and to predict the through-space proton NMR shielding increment surfaces above benzene complexed with ammonium, lithium, sodium, potassium, magnesium or calcium ion. The sum of the calculated isotropic shielding values for the proximal hydrogen of a diatomic hydrogen probe over benzene and those calculated at appropriate positions relative to cations were subtracted from the isotropic shielding values calculated for the complexes. The result is a shielding increment for complexation. Complexation results in a synergistic effect on NMR shielding. Enhanced shielding was observed over the pi electron cloud of benzene upon complexation with the cations, more than the sum of the separate effects of the aromatic ring and the charge. The results are interpreted in terms of polarization of the pi cloud of benzene by the cation and its consequences.
More Related Videos
19:58Palladium N-Heterocyclic Carbene Complexes: Synthesis from Benzimidazolium Salts and Catalytic Activity in Carbon-carbon Bond-forming Reactions
Published on: July 30, 2017
14:44Structure and Coordination Determination of Peptide-metal Complexes Using 1D and 2D 1H NMR
Published on: December 16, 2013
Related Concept Videos
π Electron Effects on Chemical Shift: Aromatic and Antiaromatic Compounds
π Electron Effects on Chemical Shift: Overview
NMR Spectroscopy of Aromatic Compounds
Aromatic Hydrocarbon Anions: Structural Overview
Due to the absence of continuous overlap of p...
Diamagnetic Shielding of Nuclei: Local Diamagnetic Current
Aromatic Hydrocarbon Cations: Structural Overview
Removing one hydrogen from the intervening CH2 group with both...