Enantiomeric electro-oxidation of d- and l-glucose on chiral gold single crystal surfaces

Abstract

The enantioselectivity of the gold chiral surfaces towards the electrocatalytic oxidation of d- and l-glucose in neutral phosphate-buffered media is reported. Two enantiomorphic surfaces were used, Au{3 2 1} R and Au{3 2 1} S, and results obtained by cyclic voltammetry were compared with two non-chiral surfaces having the same terrace and step orientations, Au(1 1 1) and Au(2 1 1). An enantioselective effect is observed, Au{3 2 1} R exhibits a higher activity for d-glucose while Au{3 2 1} S exhibits a higher activity for l-glucose. The corresponding enantioselectivity factor was estimated to 10% for the process occurring at lower potential values and to 50% for the process at higher potential values. These results represent the first evidence that gold chiral surfaces are capable of enantiomeric discrimination.