Dioxygen Activation by a Macrocyclic Copper Complex Leads to a Cu2O2 Core with Unexpected Structure and Reactivity

Isaac Garcia-Bosch, Ryan E. Cowley, Daniel E. Díaz, Maxime A. Siegler, Wonwoo Nam, Edward I. Solomon, Kenneth D. Karlin

Research output: Contribution to journalArticlepeer-review

20 Scopus citations

Abstract

We report the CuI/O2 chemistry of complexes derived from the macrocylic ligands 14-TMC (1,4,8,11-tetramethyl-1,4,8,11-tetraazacyclotetradecane) and 12-TMC (1,4,7,10-tetramethyl-1,4,7,10-tetraazacyclododecane). While [(14-TMC)CuI]+ is unreactive towards dioxygen, the smaller analog [(12-TMC)CuI(CH3CN)]+ reacts with O2 to give a side-on bound peroxo-dicopper(II) species (SP), confirmed by spectroscopic and computational methods. Intriguingly, 12-TMC as a N4 donor ligand generates SP species, thus in contrast with the previous observation that such species are generated by N2 and N3 ligands. In addition, the reactivity of this macrocyclic side-on peroxo-dicopper(II) differs from typical SP species, because it reacts only with acid to release H2O2, in contrast with the classic reactivity of Cu2O2 cores. Kinetics and computations are consistent with a protonation mechanism whereby the TMC acts as a hemilabile ligand and shuttles H+ to an isomerized peroxo core.

Original languageEnglish
Pages (from-to)5133-5137
Number of pages5
JournalChemistry - A European Journal
Volume22
Issue number15
DOIs
StatePublished - 4 Apr 2016

Keywords

  • bioinorganic chemistry
  • copper
  • dioxygen reduction
  • macrocyclic ligands
  • metal-peroxo complexes

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