Characterization of a Dinuclear (m-Hydroxo)(m-pyrazolato)dimanganese(II) Complex and Hydrolytic Equilibrium of the Bridging Pyrazolate Ligand.

Reaction of the dinuclear bis(μ-hydroxo) complex 2 with 3,5-diisopropylpyrazole yielded a dinuclear (μ-hydroxo)(μ-pyrazolato)dimanganese(II) complex 4, which reacted with H2O2 in the absence of excess pyrazole to give the mononuclear Mn(III) side-on peroxo complex containing a neutral pyrazole ligand. However, hydrolytic equilibrium of the bridging pyrazolate ligand of the (μ-hydroxo)(μ-pyrazolato)dimanganese(II) complex was observed in the presence of H2O.