Unconventional electrochemical approaches for chiral recognition

The concept of inherent chirality has gained considerable attention due to the possible synthesis of π-conjugated monomers that can be employed for preparing chiral electrode surfaces after electrooligomerization [1]. These materials have been used in enantiorecognition measurements involving chiral analytes, resulting in high selectivity based on diastereomeric interactions between the deposited enantiopure antipode and the probes dissolved in solution. In this context the high enantioselectivity of such chiral surfaces was used in combination with the mechanical and electrical properties of polypyrrole (Ppy) films to develop three new straightforward read-outs for the absolute on-off recognition of enantiomers of a chiral probe in solution; i) electromechanical deformation (a) [2], ii) electrochemically induced light emission (b) [3] and iii) self-induced enantioselective trajectories (c) [4]. These new approaches allow to convert chiral information present at the molecular level into macroscopic actuation, light emission or controlled trajectories. Furthermore, such systems allow correlating the output signal with the concentration of the enantiomers present in solution, even in the case of mixtures containing different ratios of the molecular antipodes. [1] Arnaboldi, S.; Benincori, T.; Cirilli, R.; Kutner, W.; Magni, M.; Mussini, P. R.; Noworyta, K.; Sannicolo,̀ F. Chem. Sci. 2015, 6, 1706− 1711. [2] Arnaboldi, S.; Gupta, B.; Benincori, T.; Bonetti, G.; Cirilli, R.; Kuhn, A. Anal. Chem. 2020, 92, 10042−10047. [3] Salinas, G.; Arnaboldi, S.; Bonetti, G.; Cirilli, R.; Benincori, T.; Kuhn, A. Chirality 2021, 33, 875-882. [4] Arnaboldi, S.; Salinas, G.; Karajic, A.; Garrigue, P.; Benincori, T.; Cirilli, R.; Bichon, S.; Gounel, S.; Mano, N.; Kuhn, A. Nat. Chem. 2021, 13, 1241-1247. Keywords: (inherent)chirality; bipolar electrochemistry, chiral actuator, chiral swimmers, light emitting diodes This work has been funded by the European Research Council (ERC) under the HORIZON-ERC-2021 program (grant agreement no 101040798, ERC Starting Grant CHEIR)