Enantioselectivity on naturally chiral surfaces

COLL 496

Andrew J. Gellman and Josh Horvath. Department of Chemical Engineering, Carnegie Mellon University, 5000 Forbes Avenue, Pittsburgh, PA 15213
Chiral features can be generated on surfaces by creating steps with kinks such as those that exist on the high Miller index surfaces of most crystalline materials. We have prepared chiral Cu(643) surfaces and shown that the adsorption of R-3-methylcyclohexanone on these surfaces is enantiospecific. Its interaction with the surface has been shown to occur via the carbonyl group which lies parallel to the surface when the molecule is adsorbed at the kink sites. The adsorption energy at the kinks on the Cu(643)S surface is higher than at the kinks on the Cu(643)R surface. We have shown that this can be used to induce an enantioselective separation of racemic 3-methylcyclohexanone. Exposure of the racemic mixture to the chiral surface leads to a purification to an ee > 50% in a single adsorption/desorption step.
 

Chiral Surfaces

Division of Colloid and Surface Chemistry
The 225th ACS National Meeting, New Orleans, LA, March 23-27, 2003