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Presentazione di L. Grecchi, La filosofia morale di Democrito, Mursia, Milano 2024
No full textPresentazione del volume di L. Grecchi, La filosofia morale di Democrito, Mursia, Milano 2024
Enantiomer discrimination in voltammetry in media of high structural order at the electrochemical interphase implemented with chirality
Get PDFEnantiomer discrimination in voltammetry in media of high structural order at the electrochemical interphase implemented with chirality
Patrizia Romana Mussini, Sara Grecchi, Serena Arnaboldi
Università degli Studi di Milano, Dipartimento di Chimica, Via Golgi 19, 20133 Milano
Discrimination of the enantiomers of electroactive chiral molecules in voltammetry is a fascinating frontier target. Of course the necessary condition to achieve it is that the two enantiomers undergo electron transfer in energetically different conditions. Since in an achiral context they would have identical physico chemical properties and thus also identical voltammetry features, this requires the implementation at the electrode|solution interphase of a suitable enantiopure chiral selector.
The so far most popular strategy consists in working on chiral electrode surfaces, and an impressive variety of approaches has been proposed [1,2]. However, working on achiral electrodes with chirality implemented in the medium has also been proposed [1,3], and very recent experiments have highlighted that this approach can yield outstanding discrimination in terms of potential differences for the enantiomers of chiral electroactive probes, when working in media of high structural order at the charged interphase, like ionic liquids ILs [3-7] and deep eutectic solvents DESs [8], implemented with chirality [5,6,9] or, even better, inherent chirality [4,7,8].
Such achievements will be comparatively presented and commented in terms of IL and DES structural order at the interphase (also compared to classical media and to ionic liquids / ionic liquid crystals [9]) as well as of possibility of probe/selector specific interactions.
Support to our chiral electroanalysis research line by Fondazione Cariplo/Regione Lombardia as well as by Università degli Studi di Milano is gratefully acknowledged.
[1] S. Arnaboldi, M. Magni, P.R. Mussini, Curr. Opin. Electrochem. 2018, 8, 60-72. (minireview)
[2] S. Arnaboldi, M. Magni, S. Grecchi, P.R. Mussini, Curr. Opin. Electrochem. 2018, 7, 188-189. (minireview)
[3] S. Grecchi, S. Arnaboldi, P.R. Mussini, Curr. Opin. Electrochem., accepted May 2021. (minireview)
[4] S. Rizzo, S. Arnaboldi, V. Mihali, R. Cirilli, A. Forni, A. Gennaro, A. A. Isse, M. Pierini, P. R. Mussini, F. Sannicolò, Angew. Chem. Int. Ed. 2017, 56, 2079 –2082.
[5] M. Longhi, S. Arnaboldi, E. Husanu, S. Grecchi, I. F. Buzzi, R. Cirilli, S. Rizzo, C. Chiappe, P. R. Mussini, L. Guazzelli, Electrochim. Acta 2019, 298, 194-209.
[6] S. Grecchi, C. Ferdeghini, M. Longhi, A. Mezzetta, L. Guazzelli, S. Khawthong, F. Arduini, C. Chiappe, A. Iuliano, P. R. Mussini, ChemElectroChem 2021.
[7] S. Rizzo, S. Arnaboldi, R. Cirilli, A. Gennaro, A. A. Isse, F. Sannicolò, P. R. Mussini, Electrochem. Commun. 2018, 89 57-61
[8] F. Fontana, G. Carminati, B. Bertolotti, P. R. Mussini, S. Arnaboldi, S. Grecchi, R. Cirilli, L. Micheli, S. Rizzo, Molecules 2021, 26, 311-324.
[9] S. Arnaboldi, A. Mezzetta, S. Grecchi, M. Longhi, E. Emanuele, S. Rizzo, F. Arduini, L. Micheli, L. Guazzelli, P. R. Mussini, Electrochim. Acta 202
Enantiomer discrimination in voltammetry in media of high structural order at the electrochemical interphase implemented with chirality
No full textDiscrimination of the enantiomers of electroactive chiral molecules in voltammetry is a fascinating frontier target. Of course the necessary condition to achieve it is that the two enantiomers undergo electron transfer in energetically different conditions. Since in an achiral context they would have identical physico chemical properties and thus also identical voltammetry features, this requires the implementation at the electrode|solution interphase of a suitable enantiopure chiral selector.
The so far most popular strategy consists in working on chiral electrode surfaces, and an impressive variety of approaches has been proposed [1,2]. However, working on achiral electrodes with chirality implemented in the medium has also been proposed [1], and very recent experiments have highlighted that this approach can yield outstanding discrimination in terms of potential differences for the enantiomers of chiral electroactive probes, when working in media of high structural order at the charged interphase, like ionic liquids ILs [3-7] and deep eutectic solvents DESs [8], implemented with chirality [3,4,8] or, even better, inherent chirality [5-7].
Such achievements will be comparatively presented and commented in terms of IL and DES structural order at the interphase (also compared to classical media and to ionic liquids / ionic liquid crystals [9]) as well as of possibility of probe/selector specific interactions.
Support to our chiral electroanalysis research line by Fondazione Cariplo/Regione Lombardia as well as by Università degli Studi di Milano is gratefully acknowledged.
[1] S. Arnaboldi, M. Magni, P.R. Mussini, Enantioselective selectors for chiral electrochemistry and electroanalysis: Stereogenic elements and enantioselection performance, Curr. Opin. Electrochem. 8 (2018) 60-72. (minireview)
[2] S. Arnaboldi, M. Magni, S. Grecchi, P.R. Mussini, Electroactive chiral oligo- and polymer layers for electrochemical recognition, Curr. Opin. Electrochem. 7 (2018) 188-189. (minireview)
[3] M. Longhi, S. Arnaboldi, E. Husanu, S. Grecchi, I. FrancoBuzzi, R. Cirilli, S. Rizzo, C. Chiappe, P. R. Mussini, L. Guazzelli, A family of chiral ionic liquids from the natural pool: Relationships between structure and functional properties and electrochemical enantiodiscrimination tests, Electrochim. Acta 298 (2019) 194-209.
[4] S. Grecchi, C. Ferdeghini, M. Longhi, A. Mezzetta, L. Guazzelli, S. Khawthong, F. Arduini, C. Chiappe, A. Iuliano, P. R. Mussini, Chiral biobased ionic liquids with cations or anions including bile acid building blocks as chiral selectors in voltammetry, ChemElectroChem accepted March 2021.
[5] S. Rizzo, S. Arnaboldi, V. Mihali, R. Cirilli, A. Forni, A. Gennaro, A. A. Isse, M. Pierini, P. R. Mussini, F. Sannicolò, “Inherently Chiral” Ionic‐Liquid Media: Effective Chiral Electroanalysis on Achiral Electrodes, Angew. Chem. Int. Ed. 56 (2017) 2079 –2082.
[6] S. Rizzo, S. Arnaboldi, R. Cirilli, A. Gennaro, A. A. Isse, F. Sannicolò, P. R. Mussini, An “inherently chiral” 1,1′-bibenzimidazolium additive for enantioselective voltammetry in ionic liquid media, Electrochem. Commun. 89 (2018), 57-61
[7] F. Fontana, G. Carminati, B. Bertolotti, P. R. Mussini, S. Arnaboldi, S. Grecchi, R. Cirilli, L. Micheli, S. Rizzo, Helicity: A Non-Conventional Stereogenic Element for Designing Inherently Chiral Ionic Liquids for Electrochemical Enantiodifferentiation, Molecules 26 (2021) 311-324.
[8] S. Arnaboldi, A. Mezzetta, S. Grecchi, M. Longhi, E. Emanuele, S. Rizzo, F. Arduini, L. Micheli, L. Guazzelli, P. R. Mussini, Natural-based chiral task-specific deep eutectic solvents: a novel, effective tool for enantiodiscrimination in electroanalysis, Electrochim. Acta accepted March 2021.
[9] S. Grecchi, S. Arnaboldi, S. Rizzo, P. R. Mussini Advanced chiral molecular media for enantioselective electrochemistry and electroanalysis (minireview), soon to be submitted.
NOTA: Si tratta di abstract inviato, che è stato in seguito definito "invited lecture" (e così inserito nel programma) dall'organizzatore del simposio in cui è stato presentato
Enantioselective electroanalysis for different chiral active pharmaceutical ingredients and a real matrix, using inherently chiral 2,2’-biindole based oligomer films
No full textChirality and chiral analysis constitute a key aspect of modern chemistry and chemical technologies; the enantiomeric purity of various compounds is important in different fields, especially in the pharmaceutical one [1-3].
A systematic study case is proposed, based on a new 2,2'-biindole series (N-alkyl-IND)2Ph2T4 (alkyl= methyl, propyl or hexyl group), of easy synthesis and modulable functional properties featuring systematic variation of the N alkyl substituents of the pyrrolic rings in the core [4].
The new series shows good performances when applied as selectors in chiral voltammetry for discrimination of the enantiomers of model chiral ferrocenyl probes, either in CH2Cl2, by conversion into enantiopure electroactive electrode surfaces, or in achiral ionic liquid BMIMTf2, as chiral additive (monomer with hexyl chains, hampering electrooligomerization). Discrimination is conveniently and reproducibly achieved in terms of significant potential differences for the two enantiomers, specularly inverting either probe or selector configuration. In one case successful discrimination is even observed with the two probe enantiomers concurrently present, either as racemate or with enantiomeric excesses, neatly accounted for by the peak current ratios [4].
Oligo-(N-Me-IND)2Ph2T4 films also result in enantiomer discrimination for quite different chiral probes, active pharmaceutical ingredients: terazosin, lansoprazole, ramosetron and clopidogrel, working in aqueous buffer solution. In addition, the molecule (S)-clopidogrel was also tested in a real matrix, i.e. as the main component of the DuoPlavin®, drug in combination with acetylsalicylic acid (both active substances are antiplatelet medicines).
In all the cases, concentration calibration plots, LOD e LOQ (both on bare and modified chiral electrodes) have also been obtained, by DPV experiments.
This work confirms the wide-scope effectiveness of the new inherently chiral selectors and suggesting application to a wider pool of chiral probes of applicative interest.
[1] S. Arnaboldi, M. Magni, P. R. Mussini, Curr. Opin. Electrochem., 2018, 8, 60.
[2] S. Arnaboldi, S. Grecchi, M. Magni, P. R. Mussini, Curr. Opin. Electrochem., 2018, 7, 188.
[3] S. Arnaboldi, T. Benincori, R. Cirilli, S. Grecchi, L. Santagostini, F. Sannicolò, P. R. Mussini, Anal. Bioanal. Chem., 2016, 408 (26), 7243.
[4] L. Scapinello, S. Grecchi, S. Rossi, F. Arduini, S. Arnaboldi, A. Penoni, R. Cirilli, P. R. Mussini, T. Benincori, Chem. Eur. J., 2021, Accepted Manuscript
Innovative Chiral Materials and Media for Enantioselection in Chiral Electrochemistry and Advanced Applications in Spintronics
No full textThe highest degree of selectivity in electrochemical recognition is achieved with enantioselective electroanalysis, implying the ability to discriminate specular images of a given electroactive molecule, an issue particularly important in the biological and pharmaceutical fields [1]. In fact the enantiomers of a chiral molecule have identical physico-chemical properties and would have identical electrochemical behaviour excepting when reacting in a diastereomeric context (diastereoisomers are energetically different). Unprecedented enantiorecognition in terms of large potential differences was recently observed in analytical experiments by our research group[2], implementing:
1) enantiopure electrode surfaces based on inherently chiral heterocycle-based electroactive films (with different stereogenic elements, C2 axis vs helix);
2) enantiopure media based on inherently chiral (or simply chiral) ionic liquids or related additives dissolved in an achiral medium [3,4];
3) Deep Eutectic Solvents (DES), commonly defined as systems composed of a mixture of at least two components, a hydrogen bond acceptor (HBA) and a hydrogen bond donor (HBD).
An even more striking feature implying inherently chiral films was obtained in the frame of the CISS (Chiral Induced Spin Selectivity) effect, recently unveiled by Ron Naaman and co-workers, where spin polarization in photo-ejected electrons transmitted through a thin layer of enantiopure material on gold was observed [5]. In this frame we present an innovative set-up which includes i) a non-ferromagnetic electrode (ITO) modified with a thin electroactive chiral film (the spin filter), ii) achiral redox couples dissolved in aqueous or organic solutions and iii) an external permanent magnet which was placed near the chiral film. A spectacular unforeseen effect was observed by means of cyclovoltammetry (CV), in fact CV peaks recorded in the presence of achiral redox couples reveal an impressive potential shift by flipping the magnet orientation (north vs south). This effect was also specular by changing the spin injector configuration. The importance of these studies includes possible applications in the field of spintronics, electronics, chemical sensoristic and so on and provides a striking evidence of the spin selectivity properties of chiral thin films [6].
References:
[1]S. Arnaboldi, T. Benincori, R. Cirilli, S. Grecchi, L. Santagostini, F. Sannicolò, P. R. Mussini, (2016), ABC, 408, 26, 7243.
[2]S. Arnaboldi, S. Grecchi, M. Magni, P. Mussini, (2018), Curr. Opinion, 8, 60
[3]S. Arnaboldi, M. Magni, P. Mussini, (2018), Curr. Opinion, 7, 188.
[4]M. Longhi, S. Arnaboldi, E. Husanu, S. Grecchi, I. F. Buzzi, R. Cirilli, S. Rizzo, C. Chiappe, P. R. Mussini, L. Guazzelli, (2019), Electrochimica Acta, 298, 194.
[5]B Dor, S. Yochelis, S. P. Mathew, R. Naaman, Y. Paltiel, (2013) Nat. Commun. 4, 3256.
[6]Benincori, S. Arnaboldi, M. Magni, S. Grecchi, R. Cirilli, C. Fontanesi, P. R. Mussini, (2019), Chem. Sci, 10, 2750
Spin selectivity properties displayed by chiral electrode surfaces under an external magnetic field
No full textThe combination of spintronics with magneto- electrochemistry, particularly involving truly chiral molecular spin selectors, was promoted by the discovery of the Chiral Induced Spin Selectivity (CISS) effect by Ron Naaman and coworkers, observing spin polarization in photo-ejected electrons transmitted through a thin layer of enantiopure material adsorbed on gold, acting as an electron spin filter [1].
In this frame we present an innovative set-up which includes i) a non-ferromagnetic electrode (ITO) modified with a thin electroactive chiral film (the spin filter), ii) achiral redox couples dissolved in aqueous or organic solutions and iii) an external permanent magnet which was placed near the chiral film, considering as spin filters four different types of chiral selectors (with different stereogenic elements, i.e. helix, stereogenic axis and chiral pendant). [2,3,4]
A spectacular unforeseen effect was observed by means of cyclovoltammetry (CV), in fact CV peaks recorded in the presence of achiral redox couples reveal an impressive potential shift by flipping the magnet orientation (north vs south). This effect was also specular by changing the spin injector configuration.
The importance of these studies includes possible applications in the field of spintronics, electronics, chemical sensoristic and so on and provides a striking evidence of the spin selectivity properties of chiral thin films.
References:
[1] O. B Dor, S. Yochelis, S. P. Mathew, R. Naaman, Y. Paltiel, Nat. Commun. 4 (2013), 3256.
[2] T. Benincori, S. Arnaboldi, M. Magni, S. Grecchi, R. Cirilli, C. Fontanesi, P. R. Mussini, Chem. Sci., DOI: 10.1039/C8SC04126A (2019).
[3] S. Arnaboldi, S. Cauteruccio, S. Grecchi, T. Benincori, M. Marcaccio, A. Orbelli Biroli, G. Longhi, E. Licandro P. R. Mussini, Chem. Sci., 10 (2019) 1539-1548.
[4] S. Arnaboldi, T. Benincori, A. Penoni, L. Vaghi, R. Cirilli, S. Abbate, G. Longhi, G. Mazzeo, S. Grecchi, M. Panigati, P. R. Mussini, Chem. Sci., DOI: 10.1039/C8SC04862B (2019)
Spin Filter Properties of Chiral Thin Film Highlighted by an External Magnetic Field
No full textThe study of the mutual influence between chirality, electron spin and magnetism is a well-documented field of research, in fact implications span from pure fundamental research, to chemical applications of both analytical and synthetic character, to multidisciplinary purposes.1,2 In this context the interrelated disciplines of magnetoelectrochemistry, spintronics and Spin Dependent Electrochemistry (SDE) play a crucial role. In particular, the combination of spintronics with magneto- electrochemistry, involving truly chiral molecular spin selectors, was promoted by the discovery of the Chiral Induced Spin Selectivity (CISS) effect by Ron Naaman and coworkers, observing spin polarization in photo-ejected electrons transmitted through a thin layer of enantiopure material adsorbed on gold, acting as an electron spin filter3.
Our proposed strategy is a variation of the SDE protocol, in fact the innovative set-up involves i) a non-ferromagnetic electrode (ITO as working electrode) covered by thin electroactive chiral films as electron source, ii) achiral redox couples dissolved in aqueous or organic solutions and iii) an external permanent magnet which was placed perpendicular to the electrode surface, considering as spin filters four different types of chiral selectors (with different stereogenic elements, i.e. helix, stereogenic axis and chiral pendant). 4,5,6
A spectacular unforeseen effect was observed performing cyclic voltammetry (CV) experiments under applied magnetic field, in fact the CV peaks of achiral, chemically reversible redox couples undergo impressive potential shifts by flipping the magnet orientation (north vs south), with specular results changing the film configuration.
The importance of these studies includes possible applications in the field of spintronics, electronics, chemical sensoristic and so on and provides a striking evidence of the spin selectivity properties of chiral thin films.
References:
1 G. A. Printz, Science, 1998, 282, 1660-1663.
2 P. L. Popa, N. T. Kemp, H. Majjad, G. Dalmas, V. Faramarzi, C. Andreas, R. Hertel, B. Doudin, Proc. Natl. Acad. Sci., 2014, 111, 10433-10437
3 O. B Dor, S. Yochelis, S. P. Mathew, R. Naaman, Y. Paltiel, Nat. Commun., 2013, 4, 3256-3262.
4 T. Benincori, S. Arnaboldi, M. Magni, S. Grecchi, R. Cirilli, C. Fontanesi, P. R. Mussini, Chem. Sci., 2019, 10, 2750-2757.
5 S. Arnaboldi, S. Cauteruccio, S. Grecchi, T. Benincori, M. Marcaccio, A. Orbelli Biroli, G. Longhi, E. Licandro P. R. Mussini, Chem. Sci., 2019, 10, 1539-1548.
6 . Arnaboldi, T. Benincori, A. Penoni, L. Vaghi, R. Cirilli, S. Abbate, G. Longhi, G. Mazzeo, S. Grecchi, M. Panigati, P. R. Mussini, Chem. Sci., 2019, 10, 2708-2717
“Prospettive rinnovate”. Biblioteca nella ex chiesa di San Ponziano a Lucca, in Italia, di Stefano Dini.
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