Synthesis and Characterization of a Binuclear Iron(III) Complex Bridged by 1-Aminocyclopropane-1-carboxylic Acid. Ethylene Production in the Presence of Hydrogen Peroxide

A μ-oxo-diiron(III) complex bridged by two molecules of 1-aminocyclopropane-1-carboxylic acid (ACCH) was prepared with the ligand 1,4,7-triazacyclononane (TACN): [(TACN)Fe2(μ-O)(μ-ACCH)2](ClO4)4·2H2O (1). This complex was characterized, and its crystal structure was solved. The bridging amino acid moieties were found in their zwitterionic forms (noted as ACCH). Reactivity assays were performed in the presence of hydrogen peroxide, and 1 turned out to be the first example of a well-characterized iron−ACCH complex able to produce ethylene from the bound ACCH moiety. The reaction requires the presence of a few equivalents of base, probably involved in the deprotonation of the amine groups of the ACCH bridges.