Cleavage of cluster iron-sulfide bonds in cyclophane-coordinated FenSm complexes

Abstract

Reaction of the tri(μ-sulfido)triiron(iii) tris(β-diketiminate) cyclophane complex, Fe₃S₃L^Et/Me (1), or of the di(μ-sulfido)diiron(iii) complex Fe₂S₂HL^Et/Me (5), with the related tri(bromide)triiron(ii) complex Fe₃Br₃L^Et/Me (2) results in electron and ligand redistribution to yield the mixed-ligand multiiron complexes, including Fe₃Br₂SL^Et/Me (3) and Fe₂Br₂SHL^Et/Me (4). The cleavage and redistribution observed in these complexes is reminiscent of necessary Fe-S bond cleavage for substrate activation in nitrogenase enzymes, and provides a new perspective on the lability of Fe-S bonds in FeS clusters.