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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
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
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)
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 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
Surgiplanner: A new method for one step oral rehabilitation of severe atrophic maxilla
No full textThe implant-prosthetic rehabilitation of edentulous upper jaws has always been complex for surgeons and dentists. The lack of bone in both vertical and horizontal dimension does not allow the correct insertion of dental implants. In addition, patients with edentulous upper and lower arch have a loss of vertical dimension of the face and an aged expression. Many surgical techniques have been proposed to increase the bone volume, height and thickness, such as the Le Fort I osteotomy, the bone grafts and the placement of dental implants. Planning these surgical procedures is difficult, because it is not possible to reproduce the movements of osteotomized bone segments in three planes of space. This article describes the treatment of severe atrophy maxilla with a new approach using a new instrument named â Surgiplannerâ . Surgiplanner is a method that, only using a computerized axial tomography (CAT), allows to obtain a totally predetermined therapeutic result from both an aesthetic and functional point of view, with surgery of severe resorbed jaws. Surgiplanner allows repositioning of segment of the skeleton of the patientâ s face in a predetermined and controlled way for the best implant- supported oral rehabilitatio
Il "naturalismo politico" di Aristotele e la sua concezione del ruolo del filosofo nella polis
No full textIndagine su alcuni problemi connessi con la visione "naturalistica" della politica formulata da Aristotele e analisi della questione del rapporto tra vita teoretica e vita pratica nella filosofia aristotelica, con particolare riferimento al ruolo "politico" del filosofo
Oral Rehabilitation of Bilateral Cleft Lip and Palate Patient with Simultaneous LeFort I Osteotomy and Zygomatic Implants : A Case Report
No full textThe aim of this study is to evaluate Le Fort I Osteotomy and zygomatic implantation without any graft placement for management of a cleft lip and palate patient. This case report describes oral rehabilitation of a 33-year-old patient with bilateral cleft lip-palate and oronasal fistula and atrophic pre-maxilla. As treatment, the patient received simultaneous Le Fort I osteotomy, palatoplasty and two zygomatic implant insertions. The prosthetic superstructure included zygomatic implant-supported removable hybrid prosthesis on bar locator and metal-ceramic fixed bridges in the posterior region. As conclusion, this protocol can be promising for management of patients with cleft lip-palate and malocclusion
Le tesi come momento di confronto e di studio da sfruttare; La scuola nel parco, recupero e rifunzionalizzazione di villa Cioja; Architettura e tecnologia sull’Isola Viscontea; Recupero e rifunzionalizzazione dell’ex catenificio Ri-gamonti;La rinascita di un borgo.
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