Nickel(II) complexes of bidentate N-heterocyclic carbene/phosphine ligands: Efficient catalysts for suzuki coupling of aryl chlorides

Chun Chin Lee, Wei Chi Ke, Kai Ting Chan, Chun Liang Lai, Ching Han Hu, Hon Man Lee

Research output: Contribution to journalArticle

162 Scopus citations

Abstract

Nickel(II) complexes of bidentate N-heterocyclic carbene (NHC)/phosphane ligand L were prepared and structurally characterized. Unlike palladium, which forms [PdCl2(L)], the stable nickel product isolated is the ionic [Ni(L)2]Cl2. These NiII complexes are highly robust in air. Among different N-substituents on the ligand framework, the nickel complex of ligand L bearing N-1-naphthylmethyl groups (2 a) is a highly effective catalyst for Suzuki cross-coupling between phenylboronic acid and a range of aryl halides, including unreactive aryl chlorides. The activities of 2a are largely superior to those of other reported nickel NHC complexes and their palladium counterparts. Unlike the previously reported [NiCl2(dppe)] (dppe = 1,2-bis(diphenylphosphino)ethane), 2a can effectively catalyze the cross-coupling reaction without the need for a catalytic amount of PPh 3, and this suggests that the PPh2 functionality of hybrid NHC ligand L can partially take on the role of free PPh3. However, for unreactive aryl chlorides at low catalyst loading, the presence of PPh 3, accelerates the reaction.

Original languageEnglish (US)
Pages (from-to)582-591
Number of pages10
JournalChemistry - A European Journal
Volume13
Issue number2
DOIs
StatePublished - Jan 22 2007

Keywords

  • Carbene ligands
  • Cross-coupling
  • Nickel
  • Phosphane ligands
  • Synthetic methods

ASJC Scopus subject areas

  • Catalysis
  • Organic Chemistry

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