2024-05-30

News:

How does the propagation of chirality across various length scales take place?

It unfolds within the intricate playground of virus self-assemblies – used as model system of chiral particles – to form helical liquid crystals. These chiral liquid crystals exhibit a fascinating duality: simple in structure yet complex in behavior. This work explores the physical mechanisms governing chirality transfer for two distinct virus mutants, M13 and Y21M. Despite their high structural similarity, these viruses exhibit cholesteric liquid crystalline phase phases with opposite handedness. This seemingly apparent paradox stems from the subtle interplay between steric repulsion, chiral supramolecular virus deformations, and electrostatic forces.

For the stiff Y21M virus strain, the local electrostatic interactions, which are highly sensitive to both ionic content and the detailed atomic symmetries of the capsid, play a crucial role. In this case, the molecular chirality originates primarily from the subtle helical distribution of surface charges around the symmetry axes of the capsid.

In contrast, the chirality of the M13 virus arises from weak, fluctuation-induced suprahelical deformations of its backbone. This chirality transfer and the resulting helical phase are chiefly driven by steric interactions occuring at the supramolecular length scale of the viruses themselves.

Overall, this study provides a quantitative description of chirality transfer across different length scales. It reveals the complex interplay of competing chiral interactions with opposite signs, governing the emergence of chiral structures and helical morphologies.

• Grelet, E., Tortora, M.M.C. Elucidating chirality transfer in liquid crystals of viruses. Nat. Mater. (2024). https://doi.org/10.1038/s41563-024-01897-x
• https://www.inc.cnrs.fr/fr/cnrsinfo/comment-se-forment-les-cristaux-liquides-biologiques-chiraux

Laboratory : CRPP

https://www.nature.com/articles/s41563-024-01897-x

2024-07-05

News: We discuss a role of chirality in materials, being inspired by recent studies on chirality-induced selectivity of spin and phonon angular momenta with chiral materials. A comprehensive understanding of these nontrivial phenomena will clarify the interplay between structural and dynamical chirality.
when ? 05/07, 14h-15h
where ? IECB

Laboratory : CBMN

https://www.omu.ac.jp/eng/pe1/

2024-01-16

News: Asymmetric modification of particles with various patches of different composition and size at predefined positions is an important challenge in contemporary surface chemistry, as such particles have numerous potential applications, ranging from materials science and (photo)catalysis to self-assembly and drug delivery. However, approaches allowing the synthesis of this kind of complex objects in the bulk of a solution in a straightforward way are currently lacking. In this context, bipolar electrochemistry (BE) is a powerful technique for the asymmetric modification of conducting objects. Herein, this approach is used for the highly controlled modification of particles with different metal patches, generated at specific locations of isotropic objects. The synthesis is carried out in the bulk of the solution and leads to predefined patterns of increasing complexity, including even a specific chiral arrangement of the patches.

Laboratory : ISM

https://onlinelibrary.wiley.com/doi/10.1002/adma.202307539

2023-12-20

News: Chemoresponsive microgels functionalized with enantiomeric D- or K-[Ru(bpy)3] 2+ showed tunable chiroptical properties upon swelling and shrinking. The tuning is triggered by a modulation of the local mobility of [Ru(bpy)3]2+ upon addition of fructose, controlling inter- actions and distances between [Ru(bpy)3]2+ and phenylboronic acid. DOI: 10.1039/D3CC04391F

Laboratory : CBMN/ISM/Univ. Genève/Kumamoto Univ/Tohoku Univ.

https://pubs.rsc.org/en/content/articlepdf/2024/CC/D3CC04391F

2023-12-22

News: Who ? Dr. Narcis AVARVARI du Laboratoire MOLTECH Anjou  (Université d'Angers).
Where ? salle de conférences de l'ISM (3e étage)
When ? 22 dec. 2023, 10h30-11h30
Keywords: CISS effect, eMChA effect, Helicene, Conductivity, TTF
Abstract and references on  : https://www.ism.u-bordeaux.fr/actualites/dr-narcis-avarvari

Laboratory : ISM

https://www.ism.u-bordeaux.fr/actualites/dr-narcis-avarvari

2023-09-15

News: Le PEPR LUMA invite les chercheurs travaillant dans les axes de recherche sur la chiralité listés sur : https://www.pepr-luma.fr/axes/chiralite/ de déposer des lettres d'intention (<3 pages) avant le 15 sept. 2023 afin de construire lors de workshops en visioconférence (dates prévisionnelles 27-28 sept. 2023) des consortia (typiquement 10 équipe de recherche travaillant ensemble) qui répondront aux AMI-appel à manifestation d'intérêts- auprès de l'ANR-PEPR-LUMA en automne 2023. Le template de la lettre d'intention et les dates clefs sont consultables sur : https://www.pepr-luma.fr/appels/appel-a-manifestations-dinteret-recherche-thematique/ NB : les AMI sont des financements sur 5 ans n'incluant pas de l'équipement >50 keuros.

Laboratory : chiralité

https://www.pepr-luma.fr/

2023-04-18

News: Chirality is a property of asymmetry resulting, for an object, from the non-superposition of its image in a mirror. The notion of symmetry breaking, inherent in the organization of matter, the formation of new structural edifices, and, more fundamentally, weak interactions, is omnipresent. From the physics of elementary particles to molecules of the living world and functional organisms, to climatic phenomena inducing vortices of forces, chirality often plays a crucial role. It is also a conception of geometry exploited in design fields and man-made constructions for its functionality and uniqueness. In this chapter, we will focus on the chirality observed in solid state matter, that is, chirality based on the solid state organization of atoms or molecules. While there can be an important overlap with inorganic chiral nanostructures or nanoparticles for which there are a number of reviews, the solid state matters treated in this chapter can include crystals as well as amorphous solids of both organic and inorganic molecules. As we will discuss below, the study of the chirality of solid materials has mainly been focused on asymmetric ordered and periodic structures. When atoms are considered as a repeating unit, chiral crystals of achiral molecules can be classified as 3D asymmetric periodic structures. Chiral crystal faces of centric crystals and chiral 2D patterns of achiral molecules can be classified as 2D asymmetric periodic structures. Individual helical polymeric chains, chiral carbon nanotubes, and nanoparticles can be classified as 1D asymmetric periodic structures. We should also mention that chiral quasicrystals do not have mirror symmetry or translational symmetry, but have rotational symmetry, showing beautiful chiral ordered structures. We will also describe how chirality can be enhanced by the 2D or 3D organization of building components of solid materials. We will close with a discussion of spectroscopic methods to characterize chiral objects and assemblies. Reiko Oda, Peizhao Liu, Elizabeth Hillard, Patrick Rosa, Sylvain Nlate, Yutaka Okazaki, Emilie Pouget, Yann Battie and Thierry Buffeteau
https://doi.org/10.1142/9789811259227_0006
 

Laboratory : CBMN, ISM, ICMCB, Université de Lorraine, Kyoto University

https://www.worldscientific.com/doi/abs/10.1142/9789811259227_0006

2023-04-18

News: The synthesis and characterization of diketopyrrolopyrroles and perylenemonoimidodiesters linked to a substituted benzoic acid in the ortho, meta, and para positions, are reported. Grafting of these dyes on the surface of chiral silica nanohelices is used to probe how the morphology of the platform at the mesoscopic level affects the induction of chiroptical properties onto achiral molecular chromophores. The grafted structures are weakly (diketopyrrolopyrroles) or strongly (perylenemonoimidodiesters) emissive, exhibiting both locally-excited state emission and a broad, structureless emission assigned to excimers. The dissymmetry factors obtained using circular dichroism highlight optimized supramolecular organization between the chromophores for enhancing the chiroptical properties of the system. In the ortho- derivatives, poor organization due to steric hindrance is reflected in a low density of chromophores on walls of the silica-nanostructures (<0.1 vs. >0.3 and up to 0.6 molecules/nm² for the ortho and meta or para derivatives, respectively) and lower g_abs values than in the other derivatives (g_abs<2×10⁻⁵ vs 6×10⁻⁵ for the ortho and para derivatives, respectively). The para derivatives presented a better organization and increased values of g_abs. All grafted chromophores evidence varying degrees of excimer emission which was not found to directly correlate to their grafting density.
Maria João Álvaro-Martins, José Garcés-Garcés, Antoine Scalabre, Peizhao Liu, Fernando Fernández-Lázaro, Ángela Sastre-Santos, Dario M. Bassani, Reiko Oda ChemPhysChem 2023, 24, e202200573

Laboratory : CBMN, ISM, Universidad Miguel Hernández

https://doi.org/10.1002/cphc.202200573

2023-04-18

News: Helical perovskite nanocrystals (H-PNCs) were prepared using nanometric silica helical ribbons as platforms for the in-situ growth of the crystals using supersaturated recrystallization method. The H-PNCs grow inside nanometric helical porous silica, their handedness are determined by the handedness of porous silica templates. They show strong induced circular dichroism (CD) and induced circularly polarized luminescence (CPL) signals, with very high dissymetric g-factors. Right-handed and left-handed PNCs show respectively positive and negative CD and CPL signals, with dissymmetric g-factor (abs and lum) of ~ +/- 2*10-2. Simulations based on the boundary element method demonstrate that the circular dichroism comes from the chiral shape of H-PNCs.
Peizhao Liu, Yann Battie, Takaki Kimura, Yutaka Okazaki, Piyanan Pranee, Hao Wang, Emilie Pouget, Sylvain Nlate, Takashi Sagawa, and Reiko Oda
https://doi.org/10.1021/acs.nanolett.2c04823

Laboratory : CBMN

https://doi.org/10.1021/acs.nanolett.2c04823

2023-03-15

News: The Research Federation "Chirality in Nouvelle Aquitaine" (Ki-NOA) is organizing its 2nd day of scientific meetings and exchanges on the 25th of April at the IECB (2 rue Robert Escarpit, Pessac). This event will take place from 8h50-17h15, and the program is available at https://kinoa.cnrs.fr/2nd-kinoa-meeting/ Registration mandatory before the 7th of April on the framaform sent by email.

Laboratory : all labs

https://kinoa.cnrs.fr/2nd-kinoa-meeting/