Reactivity of a 1:1 copper–oxygen complex: isolation of a Cu(II)-o-iminosemiquinonato species

While a 1:1 Cu–O2 adduct is generally unreactive with organic substrates, phosphines displace O2via an associative process and added Cu(I) leads to a novel internal ligand oxidation to yield a Cu(II)-o-iminosemiquinone complex.