Organisation of the first Ki-NOA day
https://www.icmcb-bordeaux.cnrs.fr/
Transfer of chiral information for static and dynamic electroanalytical approaches
IECB: salle Haut Brion, 15th of oct. at 11H00
All electrochemical processes are intrinsically “intelligent”; chirality can make them even smarter, endowing them with a superior level of selectivity, and making them applicable to issues of much higher added value, e.g. in the pharmaceutical and biological field, or in smart devices. In spite of this, chiral electrochemistry is still immature.
With respect to former approaches, the inherent chirality concept can provide the breakthrough. [1] In fact, it implies chirality and key functional properties, like electroactivity, to originate from the same structural element, which coincides with the main backbone of the chiral selector. Such unique identity endows the selector with extraordinary chirality manifestations and can be propagated from molecular level to the macroscopic one. Unprecedented recognition, in terms of energy differences, was recently observed, implementing inherently chiral materials both as enantiopure electrode surfaces and media. [2, 3] Recently, attractive potentialities of these systems were also exploited in the field of bipolar electrochemistry [4] and in the one of autonomous swimmers [5] allowing to correlate the output signal with the concentration of the enantiomers present in solution.
[1] 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, Potential-Driven Chirality Manifestations and Impressive Enantioselectivity by Inherently Chiral Electroactive Organic Films. 2014, ANGEWANDTE CHEMIE INTERNATIONAL EDITION, 53, 2623-2627. [2] S. Arnaboldi, T. Benincori, R. Cirilli, W. Kutner, M. Magni, P.R. Mussini, K. Noworyta, F. Sannicolò, Inherently chiral electrodes: the tool for chiral voltammetry. 2015, CHEMICAL SCIENCE, 6, 1706-1711. [3] 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. 2017, ANGEWANDTE CHEMIE INTERNATIONAL EDITION, 56, 2079-2082. [4] S. Arnaboldi, B. Gupta, T. Benincori, G. Bonetti, R. Cirilli, A. Kuhn, Absolute Chiral Recognition with Hybrid Wireless Electrochemical Actuators. 2020, ANALYTICAL CHEMISTRY, 10.1021/acs.analchem.0c01817. [5] S. Arnaboldi; G. Salinas; A. Karajic; P. Garrigue; T. Benincori; R. Cirilli; S. Bichon; S. Gounel; N. Mano; A. Kuhn, Direct dynamic readout of molecular chirality with autonomous enzyme driven swimmers. 2021, NATURE CHEMISTRY, 10.1038/s41557-021-00798-9.
Since Pasteur, scientists have tried to create a link between chirality and magnetism. Although basically very distinct, the two domains share a common and unique phenomenon called magneto-chiral anisotropy (MChA). MChA corresponds to a change in any flux (light, electrical current, heat, sound, etc.) going through a chiral medium, depending on whether it flows parallel or anti-parallel to an external magnetic field.
The first predictions of MChA for light appeared in the 1980s. Since then several observations of optical MChA have been reported, but the effects were quite weak and no complete quantitative analysis was presented. Now a collaboration of researchers from France and the USA have performed detailed measurements and advanced quantum-chemical calculations on well-defined model systems. They find experimentally that for these materials at low temperatures, the difference in light transmission parallel and anti-parallel to a modest magnetic field of 1 Tesla, hardly more than what a refrigerator magnet produces, can be as high as 10 %. Their calculations permit a detailed understanding of these results, and predict even higher anisotropies at higher fields or lower temperatures. The size of the effect and its in-depth understanding now open the road to applications of MChA, which can range from optical diodes to new optical data storage methods.
(read also in french, Communication by INP-CNRS) 