57Fe emission Mössbauer study of electron capture after-effects in 57Co-doped diaquadiformato complexes of the first transition series

Abstract

Emission Mössbauer spectroscopy is applied to the investigation of chemical after-effects accompanying the electron capture decay process of ⁵⁷Co within an isostructural series of ⁵⁷Co-doped diaquadiformato complexes of general formula ⁵⁷Co : M(HCO₂)₂· 2H₂O (M = Mn, Fe, Co, Ni, Cu, Zn). The experimental results are analysed within the framework of the self-radiolysis model, adjusted to allow for the appropriate influence of the host lattice on the stabilization scheme of the nucleogenic ⁵⁷Fe species. In line with previous investigations of these processes in other carboxylate-type complexes, large amounts of Fe^III are observed in the nickel-based compound, corroborating the marked propensity of host matrices with more compact structures to stabilize smaller ions in the sterically hindered substitutional sites.