Observation of Asymmetric Oxidation Catalysis with B20 Chiral Crystals

Heterogeneous processes for enantiomeric processes based on inorganic crystals have been a topic of resurgent interest. However, it remains a challenge to answer the question of what the driving forces for the emergence of homochirality in nature and chemical reactions are. Here, we propose one possible driver of enantioselectivity, namely orbital angular momentum (OAM) polarization. Enantioselective recognition of 3,4-dihydroxyphenylalanine (DOPA) was achieved by using B20 group PdGa crystals. Orbital textures of PdGa enantiomers suggest large OAM polarization for the bands near the Fermi level and carrying opposite signs. A positive or a negative magnetization in the [111] direction is expected depending on the handedness of PdGa crystal. This leads to the difference in adsorption energy between PdGa chiral crystals and DOPA molecules, depending on the pairing ability between the O 2p (DOPA) and Pd 4d orbital (PdGa). These results provide a new route to achieving enantioselectivity with pure inorganic crystals and may hold an answer to the origin of chirality in nature.