Strong Intramolecular Hydrogen Bonds and steric Effects involving C=S groups. An NMR and Computational Study.

Rita S. Elias, Bahjat A. Saaed, Fadhil S. Kamounah, Fritz Duus, Poul Erik Hansen

Research output: Contribution to journalJournal articleResearchpeer-review

Abstract

A number of 5-acyl rhodanines and thiorhodanines with bulky acyl groups (pivaloyl and adamantoyl), not previously available, have been synthesized. The compounds are shown to exist at the enol form. Structures have been calculated using both the MP2 approach and the B3LYP-GD3BJ functional and the 6-311++G(d,p) basis set. Hydrogen bond energies are estimated by subtracting energies of a structure with the OH group turned 180o from that of the intramolecularly hydrogen bonded one. Properties such as OH chemical shifts, two-bond isotope effects on 13C chemical shifts, electron densities at the bond critical point from AIM analysis, as well as the hydrogen bond energies show that the sterically hindered compounds have stronger hydrogen bonds than methyl or isopropyl derivatives. The combination of oxygen and sulphur derivatives enables a detailed analysis of hydrogen bond energies.
Original languageEnglish
JournalMagnetic Resonance in Chemistry
Volume58
Issue number2
Pages (from-to)154-162
Number of pages9
ISSN0749-1581
DOIs
Publication statusPublished - 1 Jan 2020

Keywords

  • hydrogen bonding
  • thiorhodaniner

Cite this

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title = "Strong Intramolecular Hydrogen Bonds and steric Effects involving C=S groups. An NMR and Computational Study.",
abstract = "A number of 5-acyl rhodanines and thiorhodanines with bulky acyl groups (pivaloyl and adamantoyl), not previously available, have been synthesized. The compounds are shown to exist at the enol form. Structures have been calculated using both the MP2 approach and the B3LYP-GD3BJ functional and the 6-311++G(d,p) basis set. Hydrogen bond energies are estimated by subtracting energies of a structure with the OH group turned 180o from that of the intramolecularly hydrogen bonded one. Properties such as OH chemical shifts, two-bond isotope effects on 13C chemical shifts, electron densities at the bond critical point from AIM analysis, as well as the hydrogen bond energies show that the sterically hindered compounds have stronger hydrogen bonds than methyl or isopropyl derivatives. The combination of oxygen and sulphur derivatives enables a detailed analysis of hydrogen bond energies.",
keywords = "Intramolecular hydrogen bonding, isotope effects, steric effects, adamantane derivatives, thiorhodanines, hydrogen bonding, thiorhodaniner",
author = "Elias, {Rita S.} and Saaed, {Bahjat A.} and Kamounah, {Fadhil S.} and Fritz Duus and Hansen, {Poul Erik}",
year = "2020",
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doi = "10.1002/mrc.4959",
language = "English",
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journal = "Magnetic Resonance in Chemistry",
issn = "0749-1581",
publisher = "JohnWiley & Sons Ltd.",
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Strong Intramolecular Hydrogen Bonds and steric Effects involving C=S groups. An NMR and Computational Study. / Elias, Rita S.; Saaed, Bahjat A.; Kamounah, Fadhil S.; Duus, Fritz; Hansen, Poul Erik.

In: Magnetic Resonance in Chemistry, Vol. 58, No. 2, 01.01.2020, p. 154-162.

Research output: Contribution to journalJournal articleResearchpeer-review

TY - JOUR

T1 - Strong Intramolecular Hydrogen Bonds and steric Effects involving C=S groups. An NMR and Computational Study.

AU - Elias, Rita S.

AU - Saaed, Bahjat A.

AU - Kamounah, Fadhil S.

AU - Duus, Fritz

AU - Hansen, Poul Erik

PY - 2020/1/1

Y1 - 2020/1/1

N2 - A number of 5-acyl rhodanines and thiorhodanines with bulky acyl groups (pivaloyl and adamantoyl), not previously available, have been synthesized. The compounds are shown to exist at the enol form. Structures have been calculated using both the MP2 approach and the B3LYP-GD3BJ functional and the 6-311++G(d,p) basis set. Hydrogen bond energies are estimated by subtracting energies of a structure with the OH group turned 180o from that of the intramolecularly hydrogen bonded one. Properties such as OH chemical shifts, two-bond isotope effects on 13C chemical shifts, electron densities at the bond critical point from AIM analysis, as well as the hydrogen bond energies show that the sterically hindered compounds have stronger hydrogen bonds than methyl or isopropyl derivatives. The combination of oxygen and sulphur derivatives enables a detailed analysis of hydrogen bond energies.

AB - A number of 5-acyl rhodanines and thiorhodanines with bulky acyl groups (pivaloyl and adamantoyl), not previously available, have been synthesized. The compounds are shown to exist at the enol form. Structures have been calculated using both the MP2 approach and the B3LYP-GD3BJ functional and the 6-311++G(d,p) basis set. Hydrogen bond energies are estimated by subtracting energies of a structure with the OH group turned 180o from that of the intramolecularly hydrogen bonded one. Properties such as OH chemical shifts, two-bond isotope effects on 13C chemical shifts, electron densities at the bond critical point from AIM analysis, as well as the hydrogen bond energies show that the sterically hindered compounds have stronger hydrogen bonds than methyl or isopropyl derivatives. The combination of oxygen and sulphur derivatives enables a detailed analysis of hydrogen bond energies.

KW - Intramolecular hydrogen bonding

KW - isotope effects

KW - steric effects

KW - adamantane derivatives

KW - thiorhodanines

KW - hydrogen bonding

KW - thiorhodaniner

U2 - 10.1002/mrc.4959

DO - 10.1002/mrc.4959

M3 - Journal article

VL - 58

SP - 154

EP - 162

JO - Magnetic Resonance in Chemistry

JF - Magnetic Resonance in Chemistry

SN - 0749-1581

IS - 2

ER -