2008 Joint Annual Meeting (5-9 Oct. 2008): Quantum Chemical Modeling of Biologically-Mediated Fe(III) Reduction

Experiments and quantum mechanical calculations are used to shed light on the rate and mechanisms of biologically-mediated Fe(III) reduction reactions. Fe(III) is an important respiratory pathway for microorganisms in anaerobic environments which allows organic contaminants to be degraded and dissolves Fe-oxides. Combining data from stop-flow and microcalorimetry experiments with quantum mechanical calculations on heme groups and Fe(III)-EDTA provides a molecular-level mechanism for this redox reaction. Further modeling of the heme reduction of Fe-hydroxide nanoparticles is also discussed.

Quantum chemical methods are used to track the reaction path and relative thermodynamic stability of the species involved. Comparisons to experimental observations of this reaction are discussed. Principles of sub-surface metal reduction reactions are highlighted in this example that are likely to be pivotal in understanding similar metal reduction reactions.