Nickel Bis-Diphosphine Complexes: Controlling the Binding and Heterolysis of H2

Ryan M. Stolley, Jonathan M. Darmon, Parthapratim Das, Monte Helm

Research output: Contribution to journalReview article

4 Citations (Scopus)

Abstract

Two new Ni(II) complexes, the homoleptic [Ni(8PCy 2NH)2]2+ complex (8PCy 2NH = 3,7-cyclohexyl-1-amino-3,7-diphosphacyclooctane) containing two pendant amines on adjacent ligands, and the heteroleptic [Ni(8PCy 2NH)(dppe)]2+ complex (dppe = bis(diphenylphosphino)ethane) containing only a single pendant amine, have been synthesized, and their electrochemical properties are reported. The [Ni(8PCy 2NH)(dppe)]2+ complex is capable of heterolytically cleaving hydrogen, allowing for the first observation of an endo-protonated nickel hydride related to the [Ni(PR 2NR 2)2]2+ family of complexes. The [Ni(8PCy 2NH)(dppe)]2+ complex did not exhibit electrocatalytic H2 oxidation activity; however, [Ni(8PCy 2NH)2]2+ is an active electrocatalyst for H2 oxidation with a maximum turnover frequency (kobs) of 18 s-1 under 1 atm H2 at Ecat/2 = -0.71 V versus the ferrocenium/ferrocene (Cp2Fe+/0) couple. In addition to an analysis of the effect of the number of pendant amines on the rates of electrocatalytic H2 oxidation of compounds related to the [Ni(PR 2NR 2)2]2+ family, the effect of the secondary pendant amine on intermolecular deprotonation is discussed.

Original languageEnglish
Pages (from-to)2965-2974
Number of pages10
JournalOrganometallics
Volume35
Issue number17
DOIs
Publication statusPublished - Sep 12 2016

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ASJC Scopus subject areas

  • Physical and Theoretical Chemistry
  • Organic Chemistry
  • Inorganic Chemistry

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