Ph.D. Candidate (2008)

Department of Chemical Engineering
Doherty Hall Room B205
Carnegie Mellon University
Pittsburgh, PA 15213
412-268-3038 (lab)
412-268-4531 (office)
412-268-7139 (fax)

The development of enantioselective heterogeneous catalysts for the production of enantiomerically pure chiral molecules is becoming increasingly important. Enantioselective heterogeneous catalysts offer a possible way to produce many pharmaceutical and agricultural products more cheaply than current processes. One factor that prevents the broad range application of enantioselective heterogeneous processes is the lack of a molecular-level understanding of enantiospecific surface reaction mechanisms. The object of this project is to develop a molecule-level understanding of enantiospecific behaviors on some chirally templated metal surfaces, which will then guide the way for the design of heterogeneous chiral catalysts.

In this project, we will examine the enantioselectivity of Cu(100) surfaces templated with several chiral molecules. Initially, Cu(100) templated with 2-butanol will be examined using propylene oxide(PO) as a chiral probe. Here surface enantioselectivity is defined as the ratio of the saturation coverage of R-propylene oxide adsorbed on the R-2-butanol templated Pd(111) surface(RR) to the saturation coverage of R-propylene oxide adsorbed on the S-2-butanol templated Pd(111) surface(RS). From the desorption measurement of R-propylene oxide on the R and S 2-butanol modified Pd(111) surfaces we can calculate the enantioselectivity ratio RR/RS. If this ratio is equal to one, then the amount of R-propylene oxide adsorbed on R-2-butanol modified Pd(111) surface is the same as the amount of R-propylene oxide adsorbed on S-2-butanol modified Pd(111) surface and there is no enantioselectivity. However, if the ratio is significantly larger or smaller than one, that means there is some enantioselectivity.

The main tools used here will include Low Energy Electron Diffraction (LEED) to determine the surface and adsorbate overlayer structure, Temperature Programmed Desorption (TPD) to measure desorption rates and decomposition kinetics, X-ray Photoelectron Spectroscopy (XPS) to investigate species presented on the surface, and High Resolution Electron Energy Loss Spectrometer (HREELS) to obtain vibrational spectra of adsorbed species.

coming soon.