Naturally Chiral Metal Surfaces as Enantiospecific Adsorbents

Abstract

The creation of solid surfaces with intrinsic chirality is one promising route for developing novel enantiospecific processes. This paper focuses on high Miller index surfaces of pure metals such as Pt(643) and Pt(531). Many high Miller index surfaces exist that are intrinsically chiral due to their surface structure. We present a succinct naming and characterization scheme for these chiral metal surfaces. We also discuss the existence of intrinsically chiral semiconductor surfaces. After reviewing previous experimental work on chiral metal surfaces, we describe a series of atomistic simulations we have used to assess the enantiospecific adsorption properties of chiral hydrocarbons on chiral Pt surfaces. To examine the role of thermally driven surface disorder on surface chirality, we present a model for Pt step edge roughening based directly on diffusion energy barriers computed using density functional theory. Detailed simulations with this model indicate that naturally chiral metal surfaces retain their net chirality even after their local structure is disrupted by thermal step roughening.