Synthesis of mixed silylene-carbene chelate ligands from nheterocyclic silylcarbenes mediated by nickel

Gengwen Tan, Stephan Enthaler, Shigeyoshi Inoue, Burgert Blom, Matthias Driess

Research output: Contribution to journalArticlepeer-review

75 Scopus citations

Abstract

The NiII -mediated tautomerization of the N-heterocyclic hydrosilylcarbene L2Si(H)(CH2)NHC1, where L2 = CH(C=CH2)(CMe)(NAr)2, Ar = 2,6-iPr2C6H3 ; NHC = 3,4,5-trimethylimidazol-2-yliden-6-yl, leads to the first N-heterocyclic silylene (NHSi)-carbene (NHC) chelate ligand in the dibromo nickel(II) complex [L1SiD(CH2)(NHC)NiBr2]2 (L1 = CH(MeC=NAr)2). Reduction of 2 with KC8 in the presence of PMe3 as an auxiliary ligand afforded, depending on the reaction time, the N-heterocyclic silyl-NHC bromo NiII complex [L2Si(CH2)NHCNiBr(PMe3)] 3 and the unique Ni0 complex [h2(Si-H){L2Si(H)(CH2)NHC}Ni(PMe3)2] ,inf>4 featuring an agostic Si-H→!Ni bonding interaction. When 1,2-bis(dimethylphosphino)ethane (DMPE) was employed as an exogenous ligand, the first NHSi-NHC chelate-ligand-stabilized Ni0 complex [L1SiD(CH2)NHCNi(dmpe)] 5 could be isolated. Moreover, the dicarbonyl Ni0 complex 6, [L1SiD-(CH2)NHCNi(CO)2], is easily accessible by the reduction of 2 with K(BHEt3) under a CO atmosphere. The complexes were spectroscopically and structurally characterized. Furthermore, complex 2 can serve as an efficient precatalyst for Kumada-Corriu-type cross-coupling reactions.

Original languageEnglish
Pages (from-to)2214-2218
Number of pages5
JournalAngewandte Chemie International Edition in English
Volume54
Issue number7
DOIs
StatePublished - 9 Feb 2015
Externally publishedYes

Keywords

  • Cross-coupling
  • Homogeneous catalysis
  • Main-group chemistry
  • N-heterocyclic carbenes
  • Silicon

Fingerprint

Dive into the research topics of 'Synthesis of mixed silylene-carbene chelate ligands from nheterocyclic silylcarbenes mediated by nickel'. Together they form a unique fingerprint.

Cite this