Enantioselective Separation on Naturally Chiral Metal Surfaces: D,L-Aspartic Acid on Cu(3,1,17)~(R&S) Surfaces

摘要

Homochirality of amino acids, sugars, proteins, and DNA is one of the biochemical hallmarks of life on Earth. Its origins have been debated for decades. Given that minerals such as quartz were probably the first enantiomerically pure materials on Earth, it has been suggested that such materials served as chiral substrates for enantiospecific surface chemistry. Enantiospecific adsorption on the naturally chiral surfaces of minerals has been demonstrated, however, the enantiomeric excesses have been only 1-2% with a couple of examples suggesting enantiomeric excesses of ca. 10 %. Higher enantioselectivities have been observed for adsorption on chiral surfaces of organic crystals.'31 Highly enantioselective adsorption could be of enormous importance, if observed on catalytically active materials such as metals. Herein, we demonstrate that naturally chiral metal surfaces can yield much higher enantioselectivities than minerals and we provide the first definitive proof of enantioselective separation by a naturally chiral metal surface.