Inherently Chiral Electrode Surfaces and Media: Attractive Alternative Approaches to Enantioselective Electroanalysis
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Data di Pubblicazione:
2017
Citazione:
Inherently Chiral Electrode Surfaces and Media: Attractive Alternative Approaches to Enantioselective Electroanalysis / S. Arnaboldi, T. Benincori, S. Cauteruccio, E. Licandro, M. Longhi, M. Magni, R. Martinazzo, S. Rizzo, F. Sannicolò, P.R. Mussini. ((Intervento presentato al 19. convegno Euroanalysis tenutosi a Stockholm nel 2017.
Abstract:
Enantioselective electroanalysis, implying the ability to discriminate the enantiomers of
chiral molecules in terms of electrode potentials, necessarily implies the electron transfer
process on which the recognition is based to take place in asymmetric conditions. This can
be achieved by the use of either a chiral electrode surface or a chiral medium. Among the
many approaches so far proposed, a groundbreaking strategy was recently introduced,,
based on the use of "inherently chiral" molecular materials, either as electrode surfaces
or as media. The peculiarity of inherently chiral molecular materials is that the same
element endows the molecule with both its key functional property and with chirality,
coinciding with the main molecular backbone, featuring a tailored torsion; this results in
outstanding chirality manifestations.
Thus, electrooligomerization of enantiopure inherently chiral electroactive monomers,
based either on biheteroaromatic atropoisomeric cores combined with thiophene-based
wings or on thiahelicene scaffolds, yields enantiopure inherently chiral electrode surfaces,
on which impressive peak potential differences are observed in voltammetric experiments
for the antipodes of chiral probes, even quite different in structure and electrochemical
activity, and of pharmaceutical interest.
Large differences in peak potentials can also be achieved for the enantiomers of different
chiral probes working on achiral electrodes, but in suitable inherently chiral media. For
instance, inherently chiral ionic liquids ICILs have been prepared from atropoisomeric 3,3'-
bicollidine, resolved into antipodes without chiral HPLC and converted into long-chain dialkyl
salts with melting points below room temperature. Both the new ICILs and shorter family
terms that are solid at room temperature, employed as low-concentration additives in
achiral ionic liquids, result in impressive peak potential differences, regularly increasing with
additive concentration, for the enantiomers of different probes on achiral electrodes.
Work is in progress to strengthen and rationalize the first proofs of concepts by developing,
characterizing and testing a wider variety of inherently chiral inductors (both monomers for
electrode surface preparation and ionic liquids/additives) with different chiral probes.
The support of Fondazione Cariplo/Regione Lombardia "Avviso congiunto per l’incremento
dell’attrattività del sistema di ricerca lombardo e della competitività dei ricercatori candidati
su strumenti ERC - edizione 2016” (Project 2016-0923) is gratefully acknowledged.
Tipologia IRIS:
14 - Intervento a convegno non pubblicato
Keywords:
electroanalysis; enantioselectivity; chiral electrochemistry; chiral electronically conducting polymer; chiral ionic liquid; chiral additive; atropisomeric; surface modified-electrode
Elenco autori:
S. Arnaboldi, T. Benincori, S. Cauteruccio, E. Licandro, M. Longhi, M. Magni, R. Martinazzo, S. Rizzo, F. Sannicolò, P.R. Mussini
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