Pair of chiral 2D silver(I) enantiomers: chiral recognition of L- and D-histidine via differential pulse voltammetry.

Self-assembly of AgPF 6 with a pair of chiral tridentate ligands (1 S ,1' S ,1'' S ,2 R ,2' R ,2'' R ) and (1 R ,1' R ,1'' R ,2 S ,2' S ,2'' S )-(benzenetricarbonyltris(azanediyl))tris(2,3-dihydro-1 H -indene-2,1-diyl)triisonicotinate ( s , r -L) and ( r , s -L) in a mixture of methanol and dioxane yields 2D sheets consisting of [Ag( s , r -L)](PF 6 )·3C 4 H 8 O 2 ·0.5H 2 O and [Ag( r , s -L)](PF 6 )·3C 4 H 8 O 2 ·0.5H 2 O, respectively. The differential pulse voltammetric (DPV) technique using the pair of chiral 2D-sheet enantiomers was employed for chiral discrimination of amino acid enantiomers, and was found to be an effective tool for enantio-recognition of L- and D-histidines. Both the size and the binding site of amino acids were strongly dependent on electrochemical enantio-recognition via the chiral 2D sheets.