Article ID | Journal | Published Year | Pages | File Type |
---|---|---|---|---|
1318206 | Journal of Inorganic Biochemistry | 2006 | 9 Pages |
Abstract
The synthesis and crystallographic characterization of a series of diiron(II) complexes with sterically hindered terphenyl carboxylate ligands and alkyl amine donors are presented. The compounds [Fe2(μ-O2CArTol)4(L)2] (L = NH2(CH2)2SBn (1); NH2(CH2)3SMe (2); NH2(CH2)3CCH (3)), where âO2CArTol is 2,6-di(p-tolyl)benzoate, and [Fe2(μ-O2CArXyl)2(O2CArXyl)2(L)2] (L = NH2(CH2)3SMe (4); NH2(CH2)3CCH (5)), where âO2CArXyl is 2,6-di(3,5-dimethylphenyl)benzoate, were prepared as small molecule mimics of the catalytic sites of carboxylate-bridged non-heme diiron enzymes. The compounds with the âO2CArTol carboxylate form tetrabridged structures, but those containing the more sterically demanding âO2CArXyl ligand have only two bridging ligands. The ancillary nitrogen ligands in these carboxylate-rich complexes incorporate potential substrates for the reactive metal centers. Their oxygenation chemistry was studied by product analysis of the organic fragments following decomposition. Compound 1 reacts with dioxygen to afford PhCHO in â¼30% yield, attributed to oxidative dealkylation of the pendant benzyl group. Compound 3 decomposes to form FeIIFeIII and FeIIIFeIV mixed-valence species by established bimolecular pathways upon exposure to dioxygen at low temperatures. Upon decomposition, the alkyne-substituted amine ligand was recovered quantitatively. When the âO2CArTol carboxylate was replaced by the âO2CArXyl ligand in 5, different behavior was observed. The six-coordinate iron(III) complex with one bidentate and two monodentate carboxylate ligands, [Fe(O2CArXyl)3(NH2(CH2)3CCH)2] (6), was isolated from the reaction mixture following oxidation.
Related Topics
Physical Sciences and Engineering
Chemistry
Inorganic Chemistry
Authors
Emily C. Carson, Stephen J. Lippard,