Copper(I) in the Cleft: Syntheses, Structures and Catalytic Properties of {Cu+–Co3+–Cu+} and {Cu+–Fe3+–Cu+} Heterobimetallic Complexes

Abstract

AbstractThe present work demonstrates the synthesis and characterization of {Cu+–Co3+–Cu+} and {Cu+–Fe3+–Cu+} heterobimetallic complexes utilizing Co3+ and Fe3+ coordination complexes as the building blocks. The crystallographic investigation of the {Cu+–Co3+–Cu+} and {Cu+–Fe3+–Cu+} heterometallic complexes reveal that the CuI ions in the clefts are coordinated by two pyridine nitrogen atoms and one CH3CN molecule. The crystal structures also show several weak interactions that result in interesting packing in the solid state. The accessible Cu2+/+ redox potential and presence of labile site on the copper center has been utilized for the oxidation of hindered phenols in the presence of molecular oxygen. Hindered phenols were oxidized to the C–C‐coupled products in most cases, however, de‐alkylation resulted in the case of 2,4,6‐trisubstituted phenols. Interestingly, when H2O2 was used as oxidant, de‐alkylation was not observed; suggesting the uniqueness of the active species generated in the presence of catalyst and molecular oxygen.