Premium
NMR, MP2, and DFT study of thiophenoxyketenimines ( o ‐thio‐Schiff bases): Determination of the preferred form
Author(s) -
Saeed Bahjat A.,
Elias Rita S.,
Kamounah Fadhil S.,
Hansen Poul Erik
Publication year - 2018
Publication title -
magnetic resonance in chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.483
H-Index - 72
eISSN - 1097-458X
pISSN - 0749-1581
DOI - 10.1002/mrc.4677
Subject(s) - chemical shift , chemistry , intramolecular force , thio , deuterium , kinetic isotope effect , computational chemistry , hydrogen bond , deuterium nmr , nmr spectra database , spectral line , carbon 13 nmr , stereochemistry , molecule , organic chemistry , physics , quantum mechanics , astronomy
Five new thiophenoxyketinimines have been synthesized. 1 H and 13 C NMR spectra as well as deuterium isotope effects on 13 C chemical shifts are determined, and spectra are assigned. DFT and MP2 calculations of both structures, chemical shifts, and isotope effects on chemical shifts are done. The combined analysis reveals that the compounds are primarily on a zwitterionic form with an NH + and a S − group and with a little of the neutral form mixed in. Very strong intramolecular hydrogen bonding is found and very high NH chemical shifts are observed. The theoretical calculations show that calculations at the MP2 level are best to obtain correct “C═S” chemical shifts.