“…Numerous functionalities with specific electronic and steric effects could be introduced in diiron systems through these chelating groups [26,27]. In light of this, we decided to use the 2,3-bis (diphenylphosphino) maleic anhydride (bma) [28][29][30][31][32][33][34] to prepare a diiron compound holding a chelating redox-active ligand as a surrogate of the [4Fe4S] cubane. As compared to 1,2-bis(diphenylphosphino)ethane (dppe, Ph 2 PCH 2 CH 2 PPh 2 ) or 1,2-bis(diphenylphosphino)ethylene (dppv, Ph 2 PCH = CHPPh 2 ), bma exhibits a radically different electronic behavior because of a low-lying π*orbital delocalized over the maleic anhydride ring [30,31].…”