Observation of Asymmetric Oxidation Catalysis with B20 Chiral Crystals

Angew Chem Int Ed Engl. 2023 Jul 3;62(27):e202303296. doi: 10.1002/anie.202303296. Epub 2023 May 15.

Abstract

The study of heterogeneous reactions for enantiomeric processes based on inorganic crystals has been resurgent in recent years. However, the question remains how homochirality develops in nature and chemical reactions. Here, the successful growth of B20 group PdGa single crystals with different chiral lattices enabled us to achieve enantioselective recognition of 3,4-dihydroxyphenylalanine (DOPA) based on a new mechanism, namely orbital angular momentum (OAM) polarization. The orbital textures of PdGa crystals indicate large OAM polarization near the Fermi level and carrying opposite signs. A positive or negative magnetization in the [111] direction is expected depending on the chiral lattice of PdGa crystals. Due to this, the adsorption energies of PdGa crystals and DOPA molecules differ depending on how well the O-2p orbital of DOPA pairs with the Pd-4d orbital of PdGa. The results provide one possible explanation for how chirality arises in nature by providing an enantioselective route with pure inorganic crystals.

Keywords: Asymmetric Oxidation; Chiral Crystals; Orbital Angular Momentum Polarization; PdGa; Spin Polarization.