Assessing the potential of zwitterionic NHOCS2 adducts for probing the stereoelectronic parameters of N-heterocyclic carbenes

Lionel Delaude, Albert Demonceau, Johan Wouters

Research output: Contribution to journalArticle

Abstract

Five imidazol(in)ium-2-dithiocarboxylates bearing cyclo-hexyl, mesityl, or 2,6-diisopropylphenyl substituents on their nitrogen atoms were prepared from the corresponding N-heterocyclic carbenes (NHCs) by reaction with carbon disul-fide. They were characterized by IR, UV/Vis, and NMR spec- troscopy, and by thermogravimetric analysis. Their molecular structures were determined by X-ray diffraction. For the sake of comparison, tricyclohexylphosphonium dithiocarboxylate was also examined. The data acquired were scrutinized to evaluate their usefulness for assessing the steric and electronic properties of NHC ligands. Because of their outstanding ability to crystallize, the five NHOCS2 betaines were found to be highly suitable for probing the steric influence of nitrogen atom substituents on imidazolylidene-based ligand precursors via XRD analysis, while the corresponding NHOCO2 adducts were deemed more appropriate for evaluating the a-donating properties of carbene ligands.

Original languageEnglish
Pages (from-to)1882-1891
Number of pages10
JournalEuropean Journal of Inorganic Chemistry
Issue number13 SPEC. ISS.
DOIs
Publication statusPublished - 1 May 2009

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Ligands
Bearings (structural)
Nitrogen
Betaine
Atoms
Ultraviolet spectroscopy
Electronic properties
Molecular structure
Nuclear magnetic resonance spectroscopy
Thermogravimetric analysis
Carbon
X ray diffraction
carbene

Keywords

  • Betaines
  • Carbenes
  • Ligand effects
  • Nitrogen heterocycles
  • Zwitterions

Cite this

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Assessing the potential of zwitterionic NHOCS2 adducts for probing the stereoelectronic parameters of N-heterocyclic carbenes. / Delaude, Lionel; Demonceau, Albert; Wouters, Johan.

In: European Journal of Inorganic Chemistry, No. 13 SPEC. ISS., 01.05.2009, p. 1882-1891.

Research output: Contribution to journalArticle

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AB - Five imidazol(in)ium-2-dithiocarboxylates bearing cyclo-hexyl, mesityl, or 2,6-diisopropylphenyl substituents on their nitrogen atoms were prepared from the corresponding N-heterocyclic carbenes (NHCs) by reaction with carbon disul-fide. They were characterized by IR, UV/Vis, and NMR spec- troscopy, and by thermogravimetric analysis. Their molecular structures were determined by X-ray diffraction. For the sake of comparison, tricyclohexylphosphonium dithiocarboxylate was also examined. The data acquired were scrutinized to evaluate their usefulness for assessing the steric and electronic properties of NHC ligands. Because of their outstanding ability to crystallize, the five NHOCS2 betaines were found to be highly suitable for probing the steric influence of nitrogen atom substituents on imidazolylidene-based ligand precursors via XRD analysis, while the corresponding NHOCO2 adducts were deemed more appropriate for evaluating the a-donating properties of carbene ligands.

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