Hydrogen Peroxide Coordination to Cobalt(II) Facilitated by Second-Sphere Hydrogen Bonding

Abstract

M(H2 O2 ) adducts have been postulated as intermediates in biological and industrial processes; however, only one observable M(H2 O2 ) adduct has been reported, where M is redox-inactive zinc. Herein, direct solution-phase detection of an M(H2 O2 ) adduct with a redox-active metal, cobalt(II), is described. This Co(II) (H2 O2 ) compound is made observable by incorporating second-sphere hydrogen-bonding interactions between bound H2 O2 and the supporting ligand, a trianionic trisulfonamido ligand. Thermodynamics of H2 O2 binding and decay kinetics of the Co(II) (H2 O2 ) species are described, as well as the reaction of this Co(II) (H2 O2 ) species with Group 2 cations.

Keywords: cobalt; hydrogen bonds; peroxides; peroxido ligands; second-sphere interactions.