The Breakthrough in Enantioselective Electrochemistry: Inherently Chiral Functional Molecular Materials

In Nature chirality has played a key role since the appearance of the first living being. Nowadays in our modern society capability to discriminate antipodes is still crucial; let us think to pharmaceutical industry: effective chiral selectors are mandatory both from an analytical and a synthetic point of view. Identifying chiral selectors able to effectively discriminate enantiomers of chiral analytes is a challenging task also for electrochemists [1,2]. In this frame our research group is working on the so called “inherently chiral functional molecular materials”, ICFMMs; the idea is simple: make the stereogenic element responsible for chirality coincident with the functional group responsible for the material specific property. This approach has constituted an actual breakthrough in chiral electrochemistry, resulting in the preparation of both chiral electroactive surfaces [3,4] and chiral media [5] invariably characterized by outstanding enantiodiscrimination ability in quite different working conditions and with chemically different chiral analytes. In this presentation a panoramic overview of our recent results will be given, pointing to a general validity of the aforementioned concept. In particular the following topics will be discussed: ICFMMs with various stereogenic elements (all of which assure a tailored torsion in the molecular backbone), screening of different chiral analytes (with different stereogenic element, too) and working media (e.g. pH, counter-ions). Very recently efforts have been focused on understanding the enantioselection mechanism, which still lacks. Results of a multi-technique characterization of the inherently chiral oligomer films will be presented, including profilometry, electrochemical impedance spectroscopy and spectroelectrochemistry measurements. References (1) Arnaboldi, S.; Magni, M.; Mussini, P. Curr. Opin. Electrochem. 2018, 8, 60. (2) Arnaboldi, S.; Grecchi, S.; Magni, M.; Mussini, P. Curr. Opin. Electrochem. 2018, 7, 188. (3) Sannicolò, F.; Arnaboldi, S.; Benincori, T.; Bonometti, V.; Cirilli, R.; Dunsch, L.; Kutner, W.; Longhi, G.; Mussini, P.R.; Panigati, M.; Pierini, M.; Rizzo S. Angew. Chem. Int. Ed. 2014, 53, 2623. (4) Arnaboldi, S.; Mussini, P.R.; Magni, M.; Sannicolò, F.; Benincori, T.; Cirilli, R.; Noworyta, K.; Kutner W. Chem. Sci. 2015, 6, 1706. (5) Rizzo S.; Arnaboldi, S.; Mihali, V.; Cirilli, R.; Forni, A; Gennaro, A.; Isse, A.A.; Pierini, M.; Mussini, P.R.; Sannicolò, F. Angew. Chem. Int. Ed. 2017, 56, 2079.