A combined approach of electronic structure calculations and spectroscopy for elucidating reaction mechanisms in organic and bioinorganic systems

• Main Author: Peck, Jamie
• Published: University of East Anglia 2012
• Subjects: 540
• Online Access: http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.572083

This thesis describes the use of density functional theory (DFT) to assist the interpretation of advanced spectroscopic techniques such as stopped flow Fourier transform infrared spectroscopy (FTIR), muon spin resonance (�SR), and nuclear inelastic scattering (NIS). These complementary techniques are used to investigate the structure and mechanism of a variety of important chemical systems, some of which are relevant to biological energy transduction and energy harvesting. The mechanisms by which [FeFe] and [NiFe] hydrogenase enzymes catalyse the reversible reduction of protons to dihydrogen are of intrinsic interest in the context of a developing hydrogen technology for energy transduction. Gas phase DFT calculations are used to simulate and assign structure to experimental solution phase FTIR spectra for a family of [FeFe]-hydrogenase model complexes. Further, the Mulliken charge distribution across the Fe centres are compared for di�erent dithiolate bridge groups and PMe3 ligand positions. In the pursuit of understanding the protonation mechanism of [FeFe]-hydrogenases, transition state theory is used and the energetics of reaction pathways leading to terminal and bridging hydrides calculated and compared. NIS demonstrates great potential for characterising the [FeFe]-hydrogenase mimics. In order to further develop and validate the technique, a combination of NIS, DFT calculations, FTIR and Raman spectroscopies are applied to a small Fe(III) model system in order to provide complete a characterisation of the low frequency metal