Enantioselective permeations of amino acids through l-proline-modified gold nanochannel membrane: an experimental and theoretical study

l -Proline-modified gold nanochannel membrane ( l -Pro-GNM) was prepared and applied for the enantioselective permeations of amino acid enantiomers including tyrosine (Tyr), tryptophan (Trp) and phenylalanine (Phe). Experimental results show that l -Pro-GNM has enantioselectivities for Tyr and Phe enantiomers. Furthermore, the chiral recognition mechanism was studied by density functional theory (DFT) and reduced density gradient (RDG). DFT computational results illustrate that the fundamental chiral recognition system contains two chiral selectors and one selectand, which can be used to evaluate the enantioselective efficiencies of other chiral compounds and the enantioselective ability of other potential amino acid-modified GNM. Finally, graphs obtained by RDG using Multiwfn show helpful visual interactions between the chiral selector and selectand. Results indicate that the electrostatic interaction and hydrogen bonding are responsible for the binding of the chiral selector and selectand, and the larger binding energy shows larger van der Waals interactions.