A New Class of Remote N-Heterocyclic Carbenes with Exceptionally Strong sigma-Donor Properties: Introducing Benzo[c]quinolin-6-ylidene

Ulrich F. J. Mayer, Elliot Murphy, Mairi F. Haddow, Michael Green, Roger W. Alder, Duncan F. Wass*

*Corresponding author for this work

Research output: Contribution to journalArticle (Academic Journal)peer-review

15 Citations (Scopus)

Abstract

We make the case for benzo[c]quinolin-6-ylidene (1) as a strongly electron-donating carbene ligand. The facile synthesis of 6-trifluoromethanesulfonylbenzo[c]quinolizinium trifluoromethanesulfonate (2) gives straightforward access to a useful precursor for oxidative addition to low-valent metals, to yield the desired carbene complexes. This concept has been achieved in the case of [Mn(benzo[c]quinolin-6-ylidene)(CO)(5)](+) (15) and [Pd(benzo[c]quinolin-6-ylidene)(PPh3)(2)(L)](2+) L=THF (21), OTf (22) or pyridine (23). Attempts to coordinate to nickel result in coupling products from two carbene precursor fragments. The CO IR-stretching-frequency data for the manganese compound suggests benzo[c]quinolin-6-ylidene is at least as strong a donor as any heteroatom-stabilised carbene ligand reported.

Original languageEnglish
Pages (from-to)4287-4299
Number of pages13
JournalChemistry - A European Journal
Volume19
Issue number13
DOIs
Publication statusPublished - Mar 2013

Structured keywords

  • BCS and TECS CDTs

Keywords

  • N-heterocyclic carbenes
  • structure elucidation
  • transition metals
  • OLEFIN METATHESIS CATALYSTS
  • CROSS-COUPLING REACTIONS
  • REDUCTIVE ELIMINATION
  • COORDINATION CHEMISTRY
  • NUCLEOPHILIC CARBENES
  • ELECTRONIC-PROPERTIES
  • MESOIONIC CARBENES
  • STABLE CARBENES
  • GOLD CATALYSIS
  • NHC LIGANDS

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