LAUSR

The adsorption of enantiopure versus racemic propylene oxide (PO) on Pd(111) is studied by temperature-programmed desorption (TPD) to explore possible differences in their saturation coverage. It is found that that the saturation coverage of enantiopure PO on Pd(111) is identical to that of racemic PO, in contrast to results on Pt(111) where significant coverage differences were found. The surface structures of enantiopure PO on Pd(111) were characterized by scanning tunneling microscopy (STM), which shows the formation of linear chains and hexagonal structures proposed to be due to freely rotating PO, in contrast to the relatively disordered PO overlayers found on Pt(111). STM experiments were carried out for enantiopure glycidol, which contains the same epoxy ring as PO, but where the methyl group of propylene oxide is replaced by a −CH2OH group to provide a hydrogen-bonding sites. Glycidol STM images show the formation of completely different surface structures; at low coverages, glycidol forms pseudoh...