title: Understanding the mechanism of H(+)-induced demetalation as a design strategy for robust iron(III) peroxide-activating catalysts.
abstract: The FeIII-TAML (tetra-amido macrocyclic ligand) activators 1 (Y = Cl) and 2 (Y = H2O), a (R = Me, X = H), b (Me, Cl), c (Me, MeO), d (Et, Cl), e (F, H), f (F, Cl), are five-coordinated in the solid state (X-ray crystallography) but are six-coordinated species in water with two H2O axial ligands. The first pKa's of aqueous ligands are in the range of 9.5-10.5. The acid-induced demetalation of 2 follows the equation kobs = k1*[H+] + k3*[H+]3. The rate constants k1* and k3* vary by 5 and 11 orders of magnitude depending on the nature of substituents R. The highest stabilization against the demetalation is achieved for R = F.
authors.affiliation: Department of Chemistry, Carnegie Mellon University, 4400 Fifth Avenue, Pittsburgh, Pennsylvania 15213, USA.
authors.forename: Anindya
authors.initials: A
authors.lastname: Ghosh
authors.forename: Alexander D
authors.initials: AD
authors.lastname: Ryabov
authors.forename: Sherry M
authors.initials: SM
authors.lastname: Mayer
authors.forename: David C
authors.initials: DC
authors.lastname: Horner
authors.forename: Duane E
authors.initials: DE
authors.lastname: Prasuhn
authors.forename: Sayam
authors.initials: S
authors.lastname: Sen Gupta
authors.forename: Leonard
authors.initials: L
authors.lastname: Vuocolo
authors.forename: Caleb
authors.initials: C
authors.lastname: Culver
authors.forename: Michael P
authors.initials: MP
authors.lastname: Hendrich
authors.forename: Cliffton E F
authors.initials: CE
authors.lastname: Rickard
authors.forename: Richard E
authors.initials: RE
authors.lastname: Norman
authors.forename: Colin P
authors.initials: CP
authors.lastname: Horwitz
authors.forename: Terrence J
authors.initials: TJ
authors.lastname: Collins
mesh_terms: D040761:Biomimetic Materials / Q000737:chemistry / Q000378:metabolism; D002384:Catalysis; D018360:Crystallography, X-Ray; D005290:Ferric Compounds / Q000737:chemistry* / Q000378:metabolism; D006863:Hydrogen-Ion Concentration; D007700:Kinetics; D010084:Oxidation-Reduction; D010545:Peroxides / Q000737:chemistry* / Q000378:metabolism; D011522:Protons
chemical_list: D005290:Ferric Compounds; D010545:Peroxides; D011522:Protons