The different (Fe4S4)3+ and /Fe4S4~+ species created by gamma irradiation in single crystals of the (Et4N)2(Fe4S4(SBenz)4) model compound: their EPR description and their biological significance

EPR studies of the (Et4N)2(FeS4(SBenz)4) model compound reveal the presence of gamma irradiation-created (Fe4S4)3+ and (Fe4S4)+ paramagnetic species in single crystals. Analysis of the 9-tensors yields principal values that agree well with the corresponding geometric and electronic structure of model compounds. The EPR spectra for (Fe4S4)3+ species allow good interpretation of a high-potential protein's oxidized state.