Design, performance and mechanistic chemistry of Fe-TAML activators: Reducing and eliminating hazardous substances

CHED 117

Terrence J. Collins,, Department of Chemistry, Carnegie Mellon University, Institute for Green Science, 4400 Fifth Avenue, Pittsburgh, PA 15213
Iron-TAML (Tetra-Amido-Macrocyclic-Ligand) activators are small molecule mimics of peroxidase enzymes. The key to their success has been a iterative design protocol carried out for 15 years to the prototype, and thereafter for further advancement, focused primarily on obtaining strongly electron-donating ligand systems where derivative complexes resist both hydrolytic and oxidative degradation. Ferric-TAML complexes with peroxides produce extremely reactive intermediates, probably several separately or jointly depending on the conditions, one of which is likely to be an iron(V)-oxo complex that has been trapped at low temperature. Fe-TAML catalysis is distinguished by low catalyst requirements (nM to low microM), efficacy under ambient conditions over a broad pH range (especially neutral to highly basic), rapidity, high efficiencies and turnover numbers, and flexibility for both selective and non-selective processes; the latter can be described as “fire-in-water”. Fe-TAML/hydrogen peroxide's use to purify water of numerous recalcitrant pollutants and hardy pathogens will be reviewed.

Transitioning into Green Chemistry
8:30 AM-12:00 PM, Monday, August 18, 2008 Sheraton Philadelphia City Center -- Independence Blrm B, Oral

Division of Chemical Education

The 236th ACS National Meeting, Philadelphia, PA, August 17-21, 2008