Characterization and Reactivity of a Tetrahedral Copper(II) Alkylperoxido Complex

A tetrahedral Cu II alkylperoxido complex [Cu II (TMG 3 tach)(OOCm)] + ( 1 OOCm ) (TMG 3 tach={2,2′,2′′‐[(1s,3s,5s)‐cyclohexane‐1,3,5‐triyl]tris‐(1,1,3,3‐tetramethyl guanidine)}, OOCm=cumyl peroxide) is prepared and characterized by UV/Vis, cold‐spray ionization mass spectroscopy (CSI‐MS), resonance Raman, and EPR spectroscopic methods. Product analysis of the self‐decomposition reaction of 1 OOCm in acetonitrile (MeCN) indicates that the reaction involves O−O bond homolytic cleavage of the peroxide moiety with concomitant C−H bond activation of the solvent molecule. When an external substrate such as 1,4‐cyclohexadiene (CHD) is added, the O−O bond homolysis leads to C−H activation of the substrate. Furthermore, the reaction of 1 OOCm with 2,6‐di‐ tert ‐butylphenol derivatives produces the corresponding phenoxyl radical species (ArO . ) together with a Cu I complex through a concerted proton‐electron transfer (CPET) mechanism. Details of the reaction mechanisms are explored by DFT calculations.