Bridging Stability and Reactivity: Novel Dinucleating Ligand With Rigid Backbone Stabilizes a Cu2O2 Side-On Peroxido Structure

Abstract

Following the goal to move chemical reactions toward more sustainable approaches, this work focuses on selective oxidative conversions of organic substrates. Inspired by the enzyme tyrosinase, a copper model complex was designed and synthesized. The ligand design was derived from previous research within this group, resulting in a dinucleating tridentate bis(pyrazolyl)methane ligand with an aromatic group as the bridging unit. Oxygenation of the corresponding Cu(I) precursor complex leads to the formation of a Cu₂O₂ species at room temperature. In addition to its catalytic activity towards selected phenolic substrates, this species exhibits remarkable stability towards temperature and water. Characterization via UV/Vis spectroscopy and mass spectrometry indicates the formation of a side-on µ-η²:η²-peroxido species. The exceptional stability of this Cu₂O₂ complex might pave the way for new and versatile applications of tyrosinase model complexes.