This three-year thesis project is aimed to deeply investigate the potentialities of the inherently chiral strategy in the chiral voltammetry field, as well as in circular dichroism and magnetoelectrochemistry ones. Voltammetric experiments must take place at chiral electrochemical interphases with the implementation of (inherently) chiral selectors, according to two strategies: i) exploitation of electrode surfaces modified with electrodeposited heterocycle-based inherently chiral oligomer films (with the stereogenic element responsible for chirality coinciding with the functional group responsible for the material specific properties); ii) use of enantiopure chiral media with high intrinsic order. Concerning the modification of electrodes with inherently chiral oligomer films, several new inherently chiral monomers were studied with different techniques, in order to amplify the range of monomer structures studied and the combination of chiral selector/probe investigated (in fact, many new chiral probes, also of pharmaceutical interest were used in enantioselection tests, with different nature, chemical structures, bulkiness and reactivity). Enantioselection tests were discussed as a function of the experimental conditions; moreover, discussion of experiments with a systematic series of planar stereogenicity ferrocenes provided key clues concerning the probe-selector interactions in the process, while experiments on a systematic new family of inherently chiral monomers with different substituents on the N atoms in the biindole core enabled to study the effect of H bonds in the enantioselection process. Finally, the inherently chiral oligomer films were discussed in advanced application for magnetoelectrochemistry experiments, employing an innovative experimental setup and resulting in impressive spin-related effects. Also concerning the chiral media approach, several new chiral selectors were presented, employing them as low concentration chiral additives in achiral commercial ionic liquids or as bulk media, testing their performances in enantioselection experiments. The performances of bio-based and synthetic chiral selectors were compared, studying different artificial inherently chiral media. The application of another kind of advanced chiral media were exploited, studying the enantioselection ability and properties of chiral Deep Eutectic Solvents (DESs) of natural origin. The DESs employed in this research project are composed of a mixture of at least two components, a hydrogen bond acceptor (HBA) and a hydrogen bond donor (HBD), which are able to self-associate to form a new eutectic phase characterized by a melting point (< 100°C) lower than that of each individual component and significantly lower than the predicted one for an ideal case.

INHERENT CHIRALITY AT WORK FOR APPLICATIONS IN CHIRAL ELECTROCHEMISTRY, CHIROPTICS AND SPINTRONICS.

GRECCHI, SARA
2022

Abstract

This three-year thesis project is aimed to deeply investigate the potentialities of the inherently chiral strategy in the chiral voltammetry field, as well as in circular dichroism and magnetoelectrochemistry ones. Voltammetric experiments must take place at chiral electrochemical interphases with the implementation of (inherently) chiral selectors, according to two strategies: i) exploitation of electrode surfaces modified with electrodeposited heterocycle-based inherently chiral oligomer films (with the stereogenic element responsible for chirality coinciding with the functional group responsible for the material specific properties); ii) use of enantiopure chiral media with high intrinsic order. Concerning the modification of electrodes with inherently chiral oligomer films, several new inherently chiral monomers were studied with different techniques, in order to amplify the range of monomer structures studied and the combination of chiral selector/probe investigated (in fact, many new chiral probes, also of pharmaceutical interest were used in enantioselection tests, with different nature, chemical structures, bulkiness and reactivity). Enantioselection tests were discussed as a function of the experimental conditions; moreover, discussion of experiments with a systematic series of planar stereogenicity ferrocenes provided key clues concerning the probe-selector interactions in the process, while experiments on a systematic new family of inherently chiral monomers with different substituents on the N atoms in the biindole core enabled to study the effect of H bonds in the enantioselection process. Finally, the inherently chiral oligomer films were discussed in advanced application for magnetoelectrochemistry experiments, employing an innovative experimental setup and resulting in impressive spin-related effects. Also concerning the chiral media approach, several new chiral selectors were presented, employing them as low concentration chiral additives in achiral commercial ionic liquids or as bulk media, testing their performances in enantioselection experiments. The performances of bio-based and synthetic chiral selectors were compared, studying different artificial inherently chiral media. The application of another kind of advanced chiral media were exploited, studying the enantioselection ability and properties of chiral Deep Eutectic Solvents (DESs) of natural origin. The DESs employed in this research project are composed of a mixture of at least two components, a hydrogen bond acceptor (HBA) and a hydrogen bond donor (HBD), which are able to self-associate to form a new eutectic phase characterized by a melting point (< 100°C) lower than that of each individual component and significantly lower than the predicted one for an ideal case.
25-mar-2022
Inglese
MUSSINI, PATRIZIA ROMANA
ARNABOLDI, SERENA
Università degli Studi di Milano
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Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/20.500.14242/78408
Il codice NBN di questa tesi è URN:NBN:IT:UNIMI-78408