[Ni(NHC)2] as a Scaffold for Structurally Characterized trans [H-Ni-PR2] and trans [R2P-Ni-PR2] Complexes

Sara Sabater, David Schmidt, Heidi Schmidt, Maximilian W. Kuntze-Fechner, Thomas Zell, Connie J. Isaac, Nasir Ahmad Rajabi, Harry Grieve, William J. M. Blackaby, John P. Lowe, Stuart Alan Macgregor, Mary F. Mahon, Udo Radius, Michael K. Whittlesey

Research output: Contribution to journalArticlepeer-review

Abstract

The addition of PPh2H, PPhMeH, PPhH2, P(para-Tol)H2, PMesH2 and PH3 to the two-coordinate Ni0 N-heterocyclic carbene species [Ni(NHC)2] (NHC=IiPr2, IMe4, IEt2Me2) affords a series of mononuclear, terminal phosphido nickel complexes. Structural characterisation of nine of these compounds shows that they have unusual trans [H−Ni−PR2] or novel trans [R2P−Ni−PR2] geometries. The bis-phosphido complexes are more accessible when smaller NHCs (IMe4>IEt2Me2>IiPr2) and phosphines are employed. P−P activation of the diphosphines R2P−PR2 (R2=Ph2, PhMe) provides an alternative route to some of the [Ni(NHC)2(PR2)2] complexes. DFT calculations capture these trends with P−H bond activation proceeding from unconventional phosphine adducts in which the H substituent bridges the Ni−P bond. P−P bond activation from [Ni(NHC)2(Ph2P−PPh2)] adducts proceeds with computed barriers below 10 kcal mol−1. The ability of the [Ni(NHC)2] moiety to afford isolable terminal phosphido products reflects the stability of the Ni−NHC bond that prevents ligand dissociation and onward reaction.

Original languageEnglish
JournalChemistry - A European Journal
Early online date4 Aug 2021
DOIs
Publication statusE-pub ahead of print - 4 Aug 2021

Keywords

  • carbene ligands
  • density functional calculations
  • hydride ligands
  • nickel
  • phosphido ligands

ASJC Scopus subject areas

  • Catalysis
  • Organic Chemistry

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