Jump to main content
Jump to site search

Issue 21, 2004
Previous Article Next Article

Nickel(III) oxidation of its glycylglycylhistamine complex

Author affiliations


The doubly-deprotonated Ni(III) complex of Gly2Ha (where Ha is histamine) undergoes base-assisted oxidative self-decomposition of the peptide. At ≤ p[H+] 7.0, a major pathway is a two-electron oxidation at the α-carbon of the N-terminal glycyl residue. Major products (up to 73%) of this two-electron oxidation are glyoxylglycylhistamine and ammonia. Glyoxylglycylhistamine will decay to give isocyanatoacetylhistamine and formaldehyde. Two-electron oxidations of the second glycyl and histamine residues occur as minor pathways (12% of the total possible reaction). Above p[H+] 8.5, two Ni(III)–peptide complexes form an oxo bridge in the axial positions to give a reactive dimer species. This proximity allows the resulting Ni(II)–peptide radical intermediates to undergo peptide–peptide cross-linking at the N-terminal glycyl residues. The products found below p[H+] 7.0 are observed above p[H+] 8.5 as well, although in lower yields. In contrast to this work, NiIII(H−2Gly2HisGly) undergoes a four-electron oxidation at the N-terminal glycyl residue. Oxidation at the internal glycyl and histidyl residues are not observed. The reactivity of NiIII(H−2Gly2Ha)+ is also different than CuIII(H−2Gly2Ha)+, which undergoes a two-electron oxidation at the histamine group with no peptide–peptide cross-linking in basic solution.

Graphical abstract: Nickel(iii) oxidation of its glycylglycylhistamine complex

Back to tab navigation

Publication details

The article was received on 30 Jun 2004, accepted on 02 Sep 2004 and first published on 20 Sep 2004

Article type: Paper
DOI: 10.1039/B409929J
Citation: Dalton Trans., 2004,0, 3508-3514
  •   Request permissions

    Nickel(III) oxidation of its glycylglycylhistamine complex

    B. J. Green, T. M. Tesfai and D. W. Margerum, Dalton Trans., 2004, 0, 3508
    DOI: 10.1039/B409929J

Search articles by author