Premium
Quantitative Four‐State Conformational Analysis by Ring Current NMR Anisotropy: A Family of Molecules Capable of Intramolecular π‐Stacking
Author(s) -
Chen Jing,
CammersGoodwin Arthur
Publication year - 2003
Publication title -
european journal of organic chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.825
H-Index - 155
eISSN - 1099-0690
pISSN - 1434-193X
DOI - 10.1002/ejoc.200300302
Subject(s) - chemistry , intramolecular force , methylene , stacking , molecule , ring (chemistry) , proton nmr , anisotropy , solvent , computational chemistry , ring flip , crystallography , stereochemistry , organic chemistry , physics , quantum mechanics
A novel, multi‐state, conformational analysis based on the magnetic anisotropy of molecules undergoing fast dynamic exchange is described. Calculated chemical shift tensors combined with experimental data from proton NMR studies were used to quantify conformational distributions as a function of solvent and temperature for a hydrocarbon and two fluorocarbon derivatives of N , N′ ‐[1,3‐phenylenebis(methylene)]bis(2‐phenylpyridinium) dibromide. Inspection for adequate analyses involved confirming that the mathematical expressions conserved magnetization (mass). Enthalpic parameters from VT‐NMR gave some indication of the nature of the impact of solvent on conformation. Results indicated that electrostatic interactions between aromatic rings can strongly impact organic conformation in solution. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2003)