With this award from the Chemistry Research Instrumentation and Facilities: Departmental Multi-User Instrumentation program (CRIF:MU), Professor Carlito Lebrilla and colleague R. David Britt from University of California at Davis will acquire an X-band EPR spectrometer. The proposal is aimed at enhancing research training and education at all levels, especially in areas of study such as (a) water splitting cobalt catalysts, (b) multielectron reduction of carbon dioxide, (c) studies of metalloproteins, (d) functionalized materials and catalysts in surfaces and zeolites, (e) silicon-doped nanoparticles, (f) polaron delocalization in conjugated polymer blends, and (g) transition metal complexes with uncommon coordination numbers and oxidation states.
An EPR spectrometer yields detailed information on the geometric and electronic structure of molecular and solid state materials. It may also be used to obtain information about the lifetimes of free radicals, short-lived, highly reactive species involved in valuable chemical transformations as well as the initiation of pathological tumor growth. These studies will impact a number of areas, from the synthesis of inorganic and organic molecules to the development of new solid state materials to compounds of biological interest. Employing examples inspired from ongoing research, this instrument will be an integral part of research and teaching at the undergraduate and graduate levels.
Electron Paramagnetic Resonance (EPR) is a magnetic resonance technique used to examine the magnetic environment of unpaired electrons in chemical and biochemical species and in materials. In Chemistry, typically these arise in organic radicals and in transition metal complexes. The Bruker Elxsys 500 EPR was installed in the UC Davis Chemistry Building Room 76 on Dec 6 and 7, 2011. The instrument is described in the CalEPR section of the R. David Britt Laboratory website: http://brittepr.ucdavis.edu. The instrument has a liquid He cryostat installed for low temperature work as required for certain samples, or it can be used at or near room temperature for aqueous solution samples. The CalEPR website provides an online scheduler (http://calepr.ucdavis.edu/calepr_scheduler) that users employ to sign up for instrument time. The instrument is typically used 6-7 days per week. Dr. Jeff Walton of the UC Davis NMR Center is primarily responsible for training new users, though this is also done by senior Britt lab personnel as well. To date, a dozen research groups at UC Davis have made us of the capabilities of the new instrument, studying enzymes with radicals or metal centers, proteins with site directed spin labels, catalysts for renewable energy, nanoparticles with applications to medicine or energy, or new main group chemical compounds. To date 30 students or postdoctoral researchers have been trained to use the E500, and of these 11 are female, one is African American, and one is Hispanic American. Twenty additional non-UC Davis research groups have made use of the Bruker E500, either through collaboration with UC Davis labs (primarily the Britt group) or by sending students or postdocs to work here. We have followed through in introducing the EPR and EPR methods to undergraduates and high school students. Co-P.I. Britt and his associates have led groups of high school exchange students on tours of the EPR lab, explaining on an introductory level how EPR helps us in energy related research. Britt introduced CW EPR research in energy to his honors general chemistry class in his lectures each year, and includes a 30 min field trip to the lab to show the students this EPR instrumentation. This tour is well received by the honors students, and several have begun undergraduate research in the lab following this introduction to EPR research. Spectra from this Bruker EPR instrument have been used in writing 16 publications, including top journals such as Science, Chemical Science, Dalton Transactions, Biochemistry, and the Journal of the American Chemical Society.
