Water-Dependent Reactions of Diiron(II) Carboxylate Complexes

Carboxylate-rich diiron(II) compounds with varying numbers of water ligands have been characterized, including the first complex with a {Fe2(μ-OH2)2(μ-O2CArTol)}3+ unit. The isolation of these complexes reveals how water can alter the structural properties of carboxylate-bridged diiron(II) core similar to those that occur in a variety of dioxygen-activating metalloenzyme cores. Mössbauer and variable temperature, variable field magnetic susceptibility experiments indicate that the compound [Fe2(μ-OH2)2(μ-O2CAr4F-Ph)(O2CAr4F-Ph)3(THF)2(OH2)] has a high-spin diiron(II) core with little significant magnetic exchange coupling.