Electrochemically Driven Directional Chirality Control for Surface-Confined Pillararenes and Its Application in Enantioselective Recognition.

The precise construction of chiral interfaces with selectively controllable conformations is crucial for enantioselective sensing. This work developed an electrochemical strategy that enables directional fixing of the planar chirality of pillararenes. By applying an oxidation or reduction electrochemical process, the chiral conformation of thiophene-modified pillar[5]arene (Th-P[5]A) can be selectively obtained in the pS or pR conformation, respectively. Molecular dynamics simulations confirmed that the oxidation and reduction conditions preferentially stabilize the pS and pR conformations, respectively. The resulting electropolymerized chiral interface serves as an excellent platform for photoelectrochemical enantioselective recognition of aspartic acid (Asp), exhibiting distinct affinity where the pR conformer preferentially recognizes l-Asp while the pS conformer shows an enhanced interaction toward d-Asp. This work establishes a straightforward method for the directional and stable chiral control of pillararenes that show great advantages as sensitive receptors for interfacial chiral sensing. The strategy presents broad potential for developing advanced enantioselective sensors and provides fundamental insights into chiral recognition mechanisms.