438451-36-6Relevant academic research and scientific papers
Modeling dioxygen-activating centers in non-heme diiron enzymes: Carboxylate shifts in diiron(II) complexes supported by sterically hindered carboxylate ligands
Lee, Dongwhan,Lippard, Stephen J.
, p. 2704 - 2719 (2002)
General synthetic routes are described for a series of diiron(II) complexes supported by sterically demanding carboxylate ligands 2,6-di(p-tolyl)benzoate (ArTolCO2-) and 2,6-di(4-fluorophenyl)benzoate (Ar4-FPhCO2-). The interlocking nature of the m-terphenyl units in self-assembled [Fe2(μ-O2CArTol)2 (O2CArTol)2L2] (L = C5H5N (4); 1-Melm (5)) promotes the formation of coordination geometries analogous to those of the non-heme diiron cores in the enzymes RNR-R2 and Δ9D. Magnetic susceptibility and Moessbauer studies of 4 and 5 revealed properties consistent with weak antiferromagnetic coupling between the high-spin iron(II) centers. Structural studies of several derivatives obtained by ligand substitution reactions demonstrated that the [Fe2(O2CAr′)4L2] (Ar′ = ArTol; Ar4-FPh) module is geometrically flexible. Details of ligand migration within the tetracarboxylate diiron core, facilitated by carboxylate shifts, were probed by solution variable-temperature 19F NMR spectroscopic studies of [Fe2(μ-O2CAr4-FPh)2 (O2CAr4-FPh)2(THF)2] (8) and [Fe2(μ-O2CAr4-FPh)4 (4-tBuC5H4N)2] (12). Dynamic motion in the primary coordination sphere controls the positioning of open sites and regulates the access of exogenous ligands, processes that also occur in non-heme diiron enzymes during catalysis.
