Applications of ultrafast 2-D infrared spectroscopy to studies of the Fe-hydrogenase enzyme system

PHYS 329

A. Ian Stewart1, M Towrie2, Ian P Clark2, Anthony W. Parker2, Saad Ibrahim3, Chris J Pickett3, and Neil T Hunt, nhunt@phys.strath.ac.uk1. (1) Department of Physics, University of Strathclyde, 107 Rottenrow East, Glasgow, G4 0NG, United Kingdom, (2) Central Laser Facility, Rutherford Appleton Laboratory, Didcot, Oxford, United Kingdom, (3) School of Chemical Sciences and Pharmacy, University of East Anglia, Univeristy Plain, Norwich, United Kingdom
Ultrafast 2D-IR spectroscopy has been applied to study the structure and vibrational dynamics of model compounds of the active site of the Fe-hydrogenase enzyme system. Studies of these model systems, which allow separation of the active site of the enzyme from the protein scaffolding allow, by comparison of 2D-IR spectra with density functional theory calculations, determination of the solution phase structure of these species. In addition, vibrational coupling and rapid (<5ps), solvent-mediated equilibration of energy between vibrationally-excited states of the carbonyl ligands of the di-iron-based active site is observed prior to relaxation to the ground state. These dynamics are shown to be solvent-dependent and form a basis for determination of the vibrational interactions between active site and protein.

The results of two-colour 2D-IR and 2D-IR studies of transient products of a photo-substitution reaction are also presented, which give new insights into vibrational energy relaxation mechanisms in similar, solution-phase metal-carbonyl systems.

 

PHYS Poster Session - Optical Probes of Dynamics in Complex Environments
7:30 PM-10:00 PM, Wednesday, April 9, 2008 Morial Convention Center -- Hall A, Poster

Sci-Mix
8:00 PM-10:00 PM, Monday, April 7, 2008 Morial Convention Center -- Hall A, Sci-Mix

Division of Physical Chemistry

The 235th ACS National Meeting, New Orleans, LA, April 6-10, 2008