Mononitrosyl Iron Complexes Supported by Sterically Hindered Carboxylate Ligands

Complexes that feature a single NO bound to Fe, as postulated in various carboxylate-rich metalloproteins, were prepared by mixing Fe^II salts, NO, and the sterically encumbered 2,6-dimesitylbenzoate (Mes₂ArCO₂^-). Among the compounds isolated are the potentially useful heterobimetallic synthon Tl(μ-Mes₂ArCO₂)₃Fe(NO) and a novel cubane Fe₄(Mes₂ArCO₂)₄(NO)₄(μ₃-OH)₄ that forms in the presence of added H₂O and features syn-[FeNO]₂ units.