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

M(H2O2) adducts have been postulated as intermediates in biological and industrial processes; however, only one observable M(H2O2) adduct has been reported, where M is redox‐inactive zinc. Herein, direct solution‐phase detection of an M(H2O2) adduct with a redox‐active metal, cobalt(II), is described. This CoII(H2O2) compound is made observable by incorporating second‐sphere hydrogen‐bonding interactions between bound H2O2 and the supporting ligand, a trianionic trisulfonamido ligand. Thermodynamics of H2O2 binding and decay kinetics of the CoII(H2O2) species are described, as well as the reaction of this CoII(H2O2) species with Group 2 cations. Endlich bewiesen: Das erste M(H2O2)‐Addukt mit einem redoxaktiven Metall, Cobalt(II), konnte direkt in Lösung nachgewiesen werden. Dabei wurden H‐Brücken‐Bindungen zwischen gebundenem H2O2 und dem Hilfsliganden, einem trianionischen Trisulfonamido‐Liganden, zur Stabilisierung genutzt. Die Zerfallskinetik und die Bindungskonstante dieser CoII(H2O2)‐Verbindung werden diskutiert.