Reactivity, Mechanistic and Spectroscopic Investigations of Iron Dependent Monooxygenase Models
tel: (617) 358-0292
email: tfoste@chem.bu.edu
B.Sc. McGill University - Honors Chemistry - May 2000
My research focusses on investigating the details of a functional model system that has been developed in the Caradonna laboratory. The dinuclear iron complex Fe2+2(Hbamb)2(NMI)(DMF)2 has been shown to carry out the oxidative chemistry on alkanes, alkenes, arenes and sulfides. This chemistry had been carried out using a variety of oxygen atom donor molecules and cleavage probes such as phenyl peracetic acid. The initial focus of my project involved examining the ability of this catalyst to induce heterolytic cleavage of the O-O bond in peroxides; the same chemistry that is exhibited by natural enzyme systems. By using the cleavage probe 2-methyl-1-phenyl-2-propyl hydroperoxide (MPPH), I have shown that the catalyst carries out its oxidative chemistry by a radical-free pathway such as that seen in the enzymes. Furthermore, I have shown that this complex can activate 3o, 2o and 1o C-H bonds in a variety of alkane substrates ranging in bond strength from 83-101 kcal/mole. This catalysis occurs via exclusively heterolytic pathways, in high turnover numbers, with complete efficiency (1 mole of peroxide decomposed per mole of product formed).
Future directions will entail a detailed spectroscopic investigation into the nature of the reactive intermediate responsible for carrying out this chemistry. Spectroscopies such as X-ray absorption, Mossbauer, Raman and Magnetic Circular Dichroism will be employed to determine the structure/electronic environment of this species. In addition to this, radical clock probes and kinetic isotope effects will be employed in order to examine the mechanism by which C-H bond activation is achieved by the catalyst/reactive species.
2003 National Research Council of Canada Post-Graduate Scholar
2002 Boston University, Feldman Graduate Award
2002 Sigma Xi Scientific Honor Society Grant in Aid of Research
Foster, T.L., Caradonna, J.P., (2002) Fe2+ Catalyzed Heterolytic RO-OH Bond Cleavage and Substrate Oxidation: A Functional Synthetic Non-Heme Iron Monooxygenase; J.A.C.S.; 125(13); 3678-79.
Foster, T.L., Spuches, A.M.; Caradonna, J.P., (2003) Catalytic Alkane Hydroxylation by a Non-Heme, Binuclear Iron Complex: primary, secondary and tertiary C-H bond activation; in preparation for J.A.C.S.
Foster, T.L., Caradonna, J.P., (2004) Non-heme Mono-iron Enzymes; Encyclopedia of Inorganic Chemistry;Sec. 8-14, Elsevier Inc.