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Powerful, Versatile Inherent Chirality at Electrochemical Interphases
No full textChirality can make electrochemistry even smarter, endowing it with a superior level of selectivity. In fact, chiral electrochemistry implies the ability to discriminate and possibly also quantify enantiomers of chiral molecules, in situ and with no preliminary separation steps, for analytical purposes; and to selectively activate or obtain the desired enantiomer of a chiral molecule, for synthetic purposes; moreover, a chiral electrochemical interphase can act as a spin filter, since electrons in rototranslational motion to/from the electrode surface are truly chiral objects.
Thus chiral electrochemistry represents an attractive area with a huge applicative potential, although mostly unexploited so far, in spite of many proposed approaches. [1]
In this context, the inherent chirality concept can provide the breakthrough. In fact, it implies chirality and key functional properties, like electroactivity, to originate from the same structural element, which can coincide with the whole backbone of the chiral selector, featuring a tailored torsion. Such unique threefold identity can endow the selector with extraordinary chirality manifestations.
Unprecedented enantiorecognition in terms of large potential differences was indeed recently observed in voltammetry experiments, implementing inherent chirality in electrochemical interphases in terms of either (a) enantiopure electrode surfaces based on inherently chiral heterocycle-based electroactive oligomer films [2-5] or (b) highly ordered enantiopure media based on inherently chiral molecular salts (either as bulk ionic liquids or as additives in achiral ionic liquids)[6,7] The property appears of general character, a given selector being effective with quite different chiral probes, and viceversa.
But such enantioselectivity has an even more wider character than that. In fact, the features of inherently chiral molecular materials can also make them outstandingly selective towards the two specular circular components of plane polarized light, resulting in outstanding chiroptical properties in both adsorption (circular dichroism) and emission (circularly polarized luminescence), even electrochemically modulable.[2,4,5] Furthermore, they could discriminate a vs b electrons in rototranslational motion to/from the electrode surface, which they are truly chiral objects; and impressive features have been recently observed in magnetoelectrochemistry experiments.[8]
Such first thrilling evidences suggest fascinating correlations worthy to be explored among chiral electrochemistry, polarized light and spin magnetic moments.
Dedicated to professor Armando Gennaro, an outstanding teacher in science and in life
Support by Regione Lombardia, Fondazione Cariplo and Università degli Studi di Milano is gratefully acknowledged.
[1] S. Arnaboldi, M. Magni, P. R. Mussini, Curr. Opin. Electrochem., 2018, 8, 60–72.
[2] F. Sannicolò, S. Arnaboldi, T. Benincori, V. Bonometti, R. Cirilli, L. Dunsch, W. Kutner, G. Longhi, P.R. Mussini, M. Panigati, M. Pierini, S. Rizzo, Angew. Chem. Int. Ed. 2014, 53, 2623-2627.
[3] S. Arnaboldi, T. Benincori, R. Cirilli, W. Kutner, M. Magni, P.R. Mussini, K. Noworyta, F. Sannicolò, Chem. Science 2015, 6, 1706-1711.
[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. 2019, 2708-2717
[5] S. Arnaboldi, S. Cauteruccio, S. Grecchi, T. Benincori, M. Marcaccio, A. Orbelli Biroli, G. Longhi, E. Licandro, P.R. Mussini, Chem.Sci. 6, 2019, 1706-1711
[6] 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.
[7] S. Rizzo, S.Arnaboldi, R. Cirilli, A. Gennaro, A. A. Isse, F. Sannicolò, P. R. Mussini, Electrochem. Comm. 2018, 89, 57-61.
[8] T. Benincori, D. Arnaboldi, M.Magni, S. Grecchi, R. Cirilli, C. Fontanesi, P.R. Mussini, Chem. Science 2019, 10, 2750-2757
Enantiomer discrimination in voltammetry in media of high structural order at the electrochemical interphase implemented with chirality
No full textEnantiomer 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
Six Ariettes nouvelles avec Accompagnement de Forte-piano ou Guittare seule dedièes. À Sa Maiesté La Reine De Prusse : Oeuvre 1 / Composées par N: Mussini Chanteur du Roi
No full textSIX ARIETTES NOUVELLES AVEC ACCOMPAGNEMENT DE FORTE-PIANO OU GUITTARE SEULE DEDIÈES. À SA MAIESTÉ LA REINE DE PRUSSE : OEUVRE 1 / COMPOSÉES PAR N: MUSSINI CHANTEUR DU ROI
Six Ariettes nouvelles avec Accompagnement de Forte-piano ou Guittare seule dedièes. À Sa Maiesté La Reine De Prusse : Oeuvre 1 / Composées par N: Mussini Chanteur du Roi
Gravé par C. C. Menzel à Zerbst (1) (1)
/ C. C. Menzel sc. a Zerbst (2) (1
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
Polifonie narrative per la costruzione di un pensiero riflessivo
No full textIl saggio presenta gli esiti di un focus group attivato all'interno di nidi e scuole dell'infanzia di Correggio teso ad approfondire pensieri e pratiche attorno al tema del rapporto tra educazione e natura
Tessere trame educative in contesti di comunità
No full textIl saggio, dopo aver delineato alcuni tratti dell'attuale crisi ecologica, presenta gli intenti pedagogici, le scelte metodologiche e le prassi operative che, a partire dall'anno 2015, hanno coinvolto nidi e scuole infanzia, famiglie e il territorio del Distretto di Correggio nel tentativo di costruire una nuova cultura ecologica e una nuova idea di educazione
L'arte di comporre storie
No full textIl saggio introduce le ragioni e i significati di un ampio progetto che ha coinvolto nidi e scuole infanzia del sistema integrato 0-6 del Distretto di Correggio volto a comprendere i modi con i quali i bambini tessono trame nei propri contesti di vita. Un dialogo, quello dei bambini, che si allarga ed include sguardi e prospettive adulte attorno alle esplorazioni e alle ricerche compiute
Approcci, esplorazioni e ricerche a contatto con la natura
No full textIl saggio presenta un itinerario progettuale con l’intento educativo di offrire ai bambini opportunità di esplorazione, scoperta e sperimentazione in contesti naturali immersivi, nella consapevolezza che il contatto diretto con la natura offre l’occasione di costruire saperi reticolari tra il dentro e il fuori, attraverso il piacere e il contatto con i materiali
Optimizing the electrodeposition protocol of enantioselective inherently chiral electrode surfaces: a multi-technique investigation
No full textWe have recently introduced "inherently chiral" enantiopure electrode surfaces of outstanding chirality manifestations, including circularly polarized luminescence, reversibly potential-driven circular dichroism, and large potential differences for the enantiomers of chiral probes in voltammetry experiments performed on such surfaces. [1-3]
The outstandingly powerful “inherent chirality” concept implies a molecular structure where the stereogenic element does not consist in an isolated stereocentre or an external chirality source, but originates from a tailored torsion in the whole main backbone endowing the molecule with its key functional property (here electroactivity).
A key issue is now to investigate the enantioselection mechanism and to optimize the experimental protocols for the deposition of our inherently chiral surfaces. For both aims it is important to study the thickness and regularity of the chiral oligomer films as a function of the experimental conditions. We started a systematic profilometry study correlated to electrochemical impedance spectroscopy measurements of the oligomer films obtained by carefully controlled electrodeposition, varying one by one different experimental parameters. The study is also important to properly compare enantioselection by films prepared from different inherently chiral monomers, including e.g. bisindole and tetrathiahelicene ones.
[1] S. Arnaboldi, S. Grecchi, M. Magni, P. Mussini, Electroactive chiral oligo- and polymer layers for electrochemical enantiorecognition, Current Opinion in Electrochemistry, 7 (2018) 188-199.
[2] S. Arnaboldi, M. Magni, P. R. Mussini, Enantioselective selectors for chiral electrochemistry and electroanalysis: Stereogenic elements and enantioselection performance, Current Opinion in Electrochemistry, 8 (2018) 60-72.
[3] S. Arnaboldi, T. Benincori, R. Cirilli, S. Grecchi, L. Santagostini, F. Sannicolò, P.R. Mussini, “Inherently chiral” thiophene-based electrodes at work: a screening of enantioselection ability toward a series of pharmaceutically relevant phenolic or catecholic amino acids, amino esters, and amine, Analytical and Bioanalytical Chemistry, 408 (2016) 7243-7254
Electroactive Inherently Chiral Surfaces at Work: Clues Toward the Elucidation of the Enantioselection Mechanism
No full textChirality is a concept strictly related to life and to its evolution. Capability to discriminate antipodes and/or produce enantiopure chiral chemicals through cheap and efficient protocols is a crucial task for our modern civilization. So identification of increasingly effective and robust chiral selectors is a challenging task also for the electrochemical community [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 (Figure, left). This approach has constituted an actual breakthrough in chiral electrochemistry, resulting in the preparation of efficient chiral electroactive surfaces [3,4,5] (and chiral additives/media, too [6]) invariably characterized by outstanding enantiodiscrimination ability in quite different working conditions and with chemically different chiral electroactive analytes. Notwithstanding plenty of proofs pointing to a general validity of the ICFMMs concept, a clear rationalization of the enantiodiscrimination mechanism still lacks.
To fill the gap a deeper knowledge of the behavior of our electrodeposited chiral films is mandatory. As a first step some of the most important experimental parameters governing the growth of the conductive coatings have been changed, one by one, to evaluate their impact on the morphological, optical and electronic properties of the final deposit. Results of the multi-technique characterization will be discussed, including profilometry, electrochemical impedance spectroscopy (Figure, right) and spectroelectrochemistry data, all aimed to collect clues useful to rationalize the way in which ICFMMs work.
The support of Fondazione Cariplo/Regione Lombardia (Project 2016-0923) and SmartMatLab are gratefully acknowledged.
References:
[1] S. Arnaboldi, M. Magni, P. Mussini, Curr. Opin. Electrochem., 2018, 8, 60.
[2] S. Arnaboldi, S. Grecchi, M. Magni, P. Mussini, Curr. Opin. Electrochem., 2018, 7, 188.
[3] F. Sannicolò, P.R. Mussini, T. Benincori, R. Martinazzo, S. Arnaboldi, G. Appoloni, M. Panigati, E. Quartapelle Procopio, V. Marino, R. Cirilli, S. Casolo, W. Kutner, K. Noworyta, A. Pietrzyk-Le, Z. Iskierko, K. Bartold, Chem. Eur. J., 2016, 22, 10839.
[4] S. Arnaboldi, P.R. Mussini, M. Magni, F. Sannicolò, T. Benincori, R. Cirilli, K. Noworyta, W. Kutner, Chem. Sci., 2015, 6, 1706.
[5] F. Sannicolò, S. Arnaboldi, T. Benincori, V. Bonometti, R. Cirilli, L. Dunsch, W. Kutner, G. Longhi, P.R. Mussini, M. Panigati, M. Pierini, S. Rizzo, Angew. Chem. Int. Ed., 2014, 53, 2623.
[6] 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
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