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

Reaction of the tri(mu-sulfido)triiron(iii) tris(beta-diketiminate) cyclophane complex, Fe3S3LEt/Me (1), or of the di(mu-sulfido)diiron(iii) complex Fe2S2HLEt/Me (5), with the related tri(bromide)triiron(ii) complex Fe3Br3LEt/Me (2) results in electron and ligand redistribution to yield the mixed-ligand multiiron complexes, including Fe3Br2SLEt/Me (3) and Fe2Br2SHLEt/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.

Automated summary

In this study, reactions between triiron complexes and sulfido or bromide complexes led to redistribution of ligands and electrons, resulting in the formation of mixed-ligand multiiron complexes. The cleavage and redistribution observed in these complexes resemble the necessary Fe-S bond cleavage for substrate activation in nitrogenase enzymes, offering a new perspective on the lability of Fe-S bonds in FeS clusters.