Nucleophilic reactivity of a copper(II)-hydroperoxo complex

Abstract

Copper(II)-hydroperoxo species are often detected as key intermediates in metalloenzymes and biomimetic compounds containing copper. However, the only reactivity has previously been observed for the copper(II)-hydroperoxo complexes is electrophilic, occurring through O-O bond cleavage. Here we report that a mononuclear end-on copper(II)-hydroperoxo complex, which has been successfully characterized by various physicochemical methods including UV-vis, rRaman, CSI-MS and EPR, is a reactive oxidant that utilizes a nucleophilic mechanism. In addition, DFT calculations fully support the electronic structure of this complex as a copper(II)-hydroperoxo complex with trigonal bipyramidal coordination geometry. A positive Hammett ρ value (2.0(3)) is observed in the reaction of copper(II)-hydroperoxo complex with para-substituted acyl chlorides, which clearly indicates nucleophilic character for the copper(II)-hydroperoxo complex. The copper(II)-hydroperoxo complex is an especially reactive oxidant in aldehyde deformylation with 2-PPA and CCA relative to the other metal-bound reactive oxygen species reported so far. The observation of nucleophilic reactivity for a copper(II)-hydroperoxo species expands the known chemistry of metal-reactive oxygen species.

Eccentricities in Spectroscopy and Reactivity of Non‐Heme Metal Intermediates Contained in Bispidine Scaffolds

“…react with aldehydes by a direct nucleophilic attack at the carbonyl centre. [83][84][85][86][87][92][93][94] Such nucleophilic deformylation reactions have been reported for several metal complexes. However, recently, a novel mechanistic pathway was discovered for aldehyde deformylation reaction.…”

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Intermediates involved in serotonin oxidation catalyzed by Cu bound Aβ peptides

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“…40,41,51,52 Most importantly the trans-1,2-peroxo species does not show any H/D shi, which is seen in a mononuclear Cu(II)-OOH species. 40,41,[51][52][53]59 Active oxidant. The Cu 2 O 2 bis(m-oxo)dicopper(III) dimer can be formed by a reaction between two equivalents of Cu-Ab and one equivalent of H 2 O 2 .…”