Supramolecular control of monooxygenase reactivity in a copper(ii) cryptate.

We report a detailed investigation of the formation and self-decomposition of Cu(ii)-hydroperoxo intermediates under the influence of second-coordination-sphere features provided by a cryptand. In solution, an equilibrium between two copper complexes with square-planar and square-pyramidal geometries was identified. Upon addition of H2O2/Et3N, two copper(ii)-hydroperoxo intermediates formed at different rates. Their decomposition via self-oxidation was probed by deuterating select positions on the cryptand. This led to a small kinetic isotope effect of 1.5. Mass spectrometry analysis of the demetallated organic products is consistent with a direct oxygen-atom transfer to a tertiary amine on the cryptand, forming an N-oxide, unlike other models of copper mononuclear monooxygenase enzymes.

Catalytic aerobic oxidation of phenols to ortho-quinones with air-stable copper precatalysts.

A range of air-stable copper species was examined for catalytic activity in the catalytic aerobic transformation of phenols into ortho-quinones. Efficient catalysis was obtained with commercially available copper(II) acetate. The stability of all constituents before mixing makes for a practical process that advances previously reported copper(I)-based oxygenations.

Ferromagnetic Coupling through Spin Polarization in a Dinuclear Copper(II) Metallacyclophane.

First organic radicals, now metal complexes: A successful extension to metal complexes of a well-known organic radical approach to ferromagnetism is exemplified by the triplet ground-state molecule containing two Cu(II) centers connected by a double m-phenylenediamide skeleton of the cyclophane type shown in the scheme.