Copper(I)-Dioxygen Reactivity in a Sterically Demanding Tripodal Tetradentate tren Ligand: Formation and Reactivity of a Mononuclear Copper(II) End-On Superoxo Complex

Abstract

Reaction of a copper(I) complex supported by a sterically demanding tripodal tetradentate ligand, HIPT₃tren, and O₂ gave a mononuclear copper(II) end-on superoxo complex. Spectroscopic (UV/Vis, resonance Raman, ESR, and ¹H-NMR) and DFT studies have been performed. The O₂-binding process as well as the reaction toward external substrates have been investigated kinetically to demonstrate the unique behavior of the copper(II) end-on superoxo complex, which may occur as a result of the existence of the hydrophobic core around the copper coordination sphere created by the HIPT₃tren ligand.

Copper(I)-dioxygen reactivity has been examined by using a sterically demanding tripodal tetradentate ligand HIPT₃tren. Low-temperature oxygenation of the copper(I) complex afforded a mononuclear copper(II) end-on superoxo complex 1 with a singlet ground state. The O₂-binding process as well as the reactivity of 1 toward external substrates has been examined kinetically.