ANR MaChiNaCo: Synthèse de nanocomposites hélicoïdales pour l’étude de propriétés magneto-chirales

Overview

In MaChiNaCo, we are designing and synthesizing magnetic nanocomposites, silica nanohelices grafted with magnetic molecules and nanoparticles, in order to observe magnetochiral dichroism (MChD). MChD is a spectroscopic phenomenon arising from the interplay between magnetism and chirality, and is a leading hypothesis for the origin of homochirality in life.1 Only a few observations of this phenomenon can be found in the literature, due to the challenge of synthesizing robust systems that are simultaneously chiral and magnetic. We propose to overcome this difficulty by synthesizing novel nanocomposites, where the magnetism component will be supplied by the magnetic achiral chromophores, and the chirality component will be supplied by the nanohelices. We have shown that such helices can induce a chiral response (circular dichroism) in grafted non-chiral molecules (see fig. and ref. 2).

The scientific objectives are threefold:

      • Record induced MChD signals for the first time.
      • Experimentally evaluate the factors controlling this phenomenon.
      • Identify nanocomposites with significant MChD in order to make the effect practical for potential technology applications.

MChD, and the intersection of magnetism and chirality in general, offers many interesting applications, such as the identification of enantiomers without polarized light, the generation of magneto-induced secondary harmonics, and a greater understanding of non-reciprocal effects. For applications, it is first necessary to understand how to increase the signal intensity. Currently, insight on the intensity of MChD signals is limited, as the studied systems studied so far are few and diverse. This approach allows the modulation of the chirality and magnetism separately in order to perform systematic studies to gain a better understanding of this exotic phenomenon in order to be able to use it for concrete applications.

1) Y. Mulyana, K. Ishii, Dalton Trans., 2014, 43, 17596; G. L. J. A. Rikken, E. Raupach, Nature, 1997, 390, 493.

2) M. Attoui, E. Pouget, R. Oda, D. Talaga, G. Le Bourdon, T. Buffeteau, S. Nlate, Chem. Eur. J., 2018, 24, 11344; N. Ryu, Y. Okazaki, K. Hirai, M. Takafuji, S. Nagaoka, E. Pouget, H. Ihara, R. Oda, Chem. Commun., 2016, 52, 5800.

 

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