NMR, MP2 and DFT Study of Thiophenoxyketenimines (o-ThioSchiff bases)

Determination of the preferred form

Bahjat Ali Saeed, Rita Sabah Elias, Fadhil S. Kamounah, Poul Erik Hansen

Publikation: Bidrag til tidsskriftTidsskriftartikelForskningpeer review

Resumé

Five new thiophenoxyketinimines have been synthesized. 1H and 13C NMR spectra as well as deuterium isotope effects on 13C 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 zwitter ionic 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.
OriginalsprogEngelsk
TidsskriftMagnetic Resonance in Chemistry
Vol/bind56
Udgave nummer3
Sider (fra-til)172-182
Antal sider11
ISSN0749-1581
DOI
StatusUdgivet - 1 mar. 2018

Emneord

  • MP2 and DFT calculations
  • zwitter ionic form
  • isotope effects on chemical shifts
  • tautomerism

Citer dette

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title = "NMR, MP2 and DFT Study of Thiophenoxyketenimines (o-ThioSchiff bases): Determination of the preferred form",
abstract = "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.",
keywords = "MP2 and DFT calculations, zwitter ionic form, isotope effects on chemical shifts, tautomerism, isotoope effects, DFT calculations, Hydrogen bond strength. , zwitter ion, tautomerism",
author = "Saeed, {Bahjat Ali} and Elias, {Rita Sabah} and Kamounah, {Fadhil S.} and Hansen, {Poul Erik}",
year = "2018",
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doi = "10.1002/mrc.4677",
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NMR, MP2 and DFT Study of Thiophenoxyketenimines (o-ThioSchiff bases) : Determination of the preferred form. / Saeed, Bahjat Ali; Elias, Rita Sabah; Kamounah, Fadhil S.; Hansen, Poul Erik.

I: Magnetic Resonance in Chemistry, Bind 56, Nr. 3, 01.03.2018, s. 172-182.

Publikation: Bidrag til tidsskriftTidsskriftartikelForskningpeer review

TY - JOUR

T1 - NMR, MP2 and DFT Study of Thiophenoxyketenimines (o-ThioSchiff bases)

T2 - Determination of the preferred form

AU - Saeed, Bahjat Ali

AU - Elias, Rita Sabah

AU - Kamounah, Fadhil S.

AU - Hansen, Poul Erik

PY - 2018/3/1

Y1 - 2018/3/1

N2 - 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.

AB - 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.

KW - MP2 and DFT calculations

KW - zwitter ionic form

KW - isotope effects on chemical shifts

KW - tautomerism

KW - isotoope effects

KW - DFT calculations

KW - Hydrogen bond strength.

KW - zwitter ion

KW - tautomerism

U2 - 10.1002/mrc.4677

DO - 10.1002/mrc.4677

M3 - Journal article

VL - 56

SP - 172

EP - 182

JO - Magnetic Resonance in Chemistry

JF - Magnetic Resonance in Chemistry

SN - 0749-1581

IS - 3

ER -