Poster Presentation 21st International Conference on Biological Inorganic Chemistry 2025

The simplest binuclear copper-dioxygen complex with nitrogenous ligation: fundamental oxidant of aerobic life? (#589)

Viet H Tran 1 , Richard Hage 1 , Tao A. G. Large 1 , T. Daniel P Stack 1
  1. Department of Chemistry, Stanford University, Palo Alto, CA, United States

Binuclear copper-dioxygen (Cu2O2) systems such as Tyrosinases enable organisms to effect selective oxidations using molecular dioxygen. Synthetic models using exclusive monodentate imidazole ligation1,2,3 recapitulate much of the structure, spectroscopy, and reactivity of such active sites, as do many simple polydentate amine ligands.4,5 Lacking are the simplest, monodentate nitrogenous ligands such as ammonia and alkylated amines.  At temperatures below -145 °C, simple monodentate amine-ligated Cu2O2 complexes can be stabilized and investigated. Their absorption features suggest not a side-on peroxide oxygenated species akin to Tyrosinases but a redox isomer, a bis-oxo CuIII species, [L4CuIII2O2]2+. A blueshift in optical features correlates with decreasing alkylation, consistent with a more compact complex, with density functional theory calculations supporting this optical trend. This work underscores the potential of Cu2O2 systems as a potential primitive oxidant in the origin of aerobic life.6

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