Reaction of the sterically hindered α-ketocarboxylate 2,6-di(mesityl)benzoylformate (MesBF) with the iron(II) complexes LFeCl 2 [L = N,N,N′,N′-tetramethylpropylenediamine (Me 4pda) or 6,6′-dimethyl-2,2′-bipyridine (dmby)] yielded LFe(Cl)(MesBF) (1 or 2). X-ray crystal structures of these complexes showed that they closely model the active site structure of the nonheme iron halogenase enzyme SyrB2. A similar synthetic procedure using benzoylformate with L = dmby yielded (dmby)Fe[(O2CC(O)Ph)]2 (3) instead, demonstrating the need for the sterically hindered α-ketocarboxylate to assemble the halogenase model compounds. In order to make reactivity comparisons among the structurally related iron(II) complexes of benzoylformates of varying steric properties, the complexes [LFe(O2CC(O)Ar)]n (4-6) were prepared, where L′ = tris(pyridylmethyl)amine (tpa) and Ar = 2,6-dimesitylphenyl, 2,6-dip-tolylphenyl, or 2,4,6-trimethylphenyl, respectively. X-ray structures for the latter two cases (5 and 6) revealed dinuclear topologies (n = 2), but UV-vis and 1H NMR spectroscopy indicated that all three complexes dissociated in varying degrees to monomers in CH2Cl2 solution. Although compounds 1-6 were oxidized by O2, oxidative decarboxylation of the α-ketocarboxylate ligand(s) only occurred for 3. These results indicate that the steric hindrance useful for structural modeling of the halogenase active site prohibits functional mimicry of the enzyme.