Modulation of circularly polarized luminescence by swelling of microgels functionalized with enantiopure [Ru(bpy)3]2+ luminophores
2023-12-20
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.

Chirality Related Properties in Helicene and Tetrathiafulvalene based Materials
2023-12-22
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

Deadline sur PEPR LUMA
2023-09-15
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

Chirogenesis in Solid State and Spontaneous Resolution
2023-04-18
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

Disentangling Excimer Emission from Chiral Induction in Nanoscale Helical Silica Scaffolds Bearing Achiral Chromophores
2023-04-18
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 gabs values than in the other derivatives (gabs<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 gabs. All grafted chromophores evidence varying degrees of excimer emission which was not found to directly correlate to their grafting density.
Maria João Álvaro-MartinsJosé Garcés-Garcés, Antoine Scalabre, Peizhao Liu, Fernando Fernández-Lázaro, Ángela Sastre-Santos, Dario M. Bassani, Reiko Oda ChemPhysChem 2023, 24, e202200573
Description unavailable
Laboratory: CBMN, ISM, Universidad Miguel Hernández

Chiral shaped perovskite nanocrystals growth inside hollow silica nanoribbons
2023-04-18
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 https://pubs.acs.org/cms/10.1021/acs.nanolett.2c04823/asset/images/large/nl2c04823_0006.jpeg
Laboratory: CBMN

The 2nd day meeting of kinoa
2023-03-15
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

The kinoa tour
2023-02-22
Nous avons eu 10 propositions de visite de labo sur le campus bordelais pour échanger autour de la chiralité. Ces visites se sont tenues entre décembre 2022 et février 2023, avec des échanges scientifiques très constructifs. Merci à tous ceux qui ont donné de leur temps et curiosité 🙂
Laboratory: all labs

2nd Kinoa Meeting-2023
Laboratory:

Félicitation à Alexander et toute l’équipe NSYSA de l’ISM
2023-03-06
Alexander Kuhn, membre très actif de la fédération kinoa, professeur à l’École nationale supérieure de matériaux, d’agroalimentaire et de chimie et chercheur à l’Institut des Sciences Moléculaires a recu l'une des 24 médailles d'argent du CNRS octroyée en 2023. Félicitation de tous à l'équipe NSYSA (NanoSystèmes Analytiques) https://www.cnrs.fr/fr/personne/alexander-kuhn
https://nsysa.ism-bordeaux.cnrs.fr/staff/permanent/22-staff/288-contact-alexander-kuhn-2.html
Laboratory: ISM

Crystal Engineering of Conglomerates: Dilution of Racemate-Forming Fe(II) and Ni(II) Congeners into Conglomerate-Forming [Zn(bpy)3](PF6)2
2023-02-28
Conglomerate formation, where enantiomers within a racemic mixture self-segregate upon crystallization, is an advantageous property for obtaining chirally pure crystals and allows large-scale chiral resolution. However, the prevalence of conglomerates is low and difficult to predict. In this report, we describe our attempts to engineer conglomerates from racemate-forming compounds by integrating them into a conglomerate-forming matrix. In this regard, we found that Ni(II) and Fe(II) form molecular alloys with Zn(II) in [MxZn(1−x)(bpy)3](PF6)2 (where bpy = 2,2′-bipyridyl). Powder X-ray Diffraction (PXRD) and Energy-Dispersive X-ray spectroscopy (EDX) evidenced conglomerate crystallization with Ni(II) concentrations up to about 25%, while it was observed only for much lower concentrations of Fe(II). This can be attributed to the ability of [Ni(bpy)3](PF6)2 to access a metastable conglomerate phase, while no such phase has been detected in [Fe(bpy)3](PF6)2. Furthermore, the chiral phase appears to be favored in fast-growing precipitates, while the racemic phase is favored in slow re-crystallizations for both Ni(II) and Fe(II) molecular alloys. X-ray natural circular dichroism (XNCD) measurements on [Ni0.13Zn0.87(bpy)3](PF6)2 demonstrate the chirality of the nickel molecules within the zinc molecular matrix.
U. Serdan, L. Robin, M. Marchivie, M. Gonidec, P. Rosa, E. Duverger-Nédellec, E. Pouget, P. Sainctavit, M.-A. Arrio, A. Juhin, A. Rogalev, F. Wilhelm and E. A. Hillard Chemistry. 5(1) (2023) 255-268
fig :Molecular alloy of conglomerate [Ni@Zn(bpy)3](PF6)2
Laboratory: ICMCB

Autonomous Chiral Microswimmers with Self‐mixing Capabilities for Highly Efficient Enantioselective Synthesis
2022-12-15
The development of chiral catalysts plays a very important role in various areas of chemical science. Heterogeneous catalysts have the general advantage of allowing a more straightforward separation from the products. One specific case of heterogeneous catalysis is electrocatalysis, being potentially a green chemistry approach. However, a typical drawback is that the redox conversion of molecules occurs only at the electrode/electrolyte interface, and not in the bulk of the electrolyte. The second limitation is that the electrodes have to be physically connected to a power supply to induce the desired reactions. To circumvent these problems, we propose here a complementary approach by replacing macroscopic electrodes with an ensemble of self-propelled redox active microswimmers. They move autonomously in solution while transforming simultaneously a prochiral starting compound into a specific enantiomer with a very high enantiomeric excess, accompanied by a significantly increased production rate of the favorite enantiomer.
S. Arnaboldi, G. Salinas, G. Bonetti, P. Garrigue, R. Cirilli, T. Benincori, A. Kuhn
Angew.Chem.Int.Ed. 61 (2022) e202209098
Laboratory: ISM

Electrochemiluminescent enantioselective detection with chiral-imprinted mesoporous metal surfaces
2022-12-15
Chiral-imprinted mesoporous Pt-Ir alloy surfaces were combined in a synergetic way with electrochemiluminescence (ECL) to detect the two enantiomers of phenylalanine (PA) as a model compound, acting simultaneously as a chiral target and as a co-reactant to generate significant differences in ECL signals. The chiral features of the metal surfaces are converted into an enantioselective electrogeneration of the excited state of the [Ru(bpy)3]2+ dye, which in fine produces the differentiating light emission with up to 20-fold differences in intensity for the two enantiomers. These findings open up the possibility of developing new ECL-based bioassays and microscopy of chiral environments.
S. Butcha, J. Yu, Z. Pasom, B. Goudeau, C. Wattanakit, N. Sojic, A. Kuhn
ChemComm 58 (2022) 10707-10710
Laboratory: ISM

Bipolar electrochemical rotors for the direct transduction of molecular chiral information
2022-12-15
Efficient monitoring of chiral information of bioactive compounds has gained considerable attention, due to their involvement in different biochemical processes. In this work, we propose a novel dynamic system for the easy and straightforward recognition of chiral redox active molecules and its possible use for the efficient measurement of enantiomeric excess in solution. The approach is based on the synergy between the localized enantioselective oxidation of only one of the two antipodes of a chiral molecule and the produced charge-compensating asymmetric proton flux along a bipolar electrode. The resulting clockwise or anticlockwise rotation is triggered only when the probe with the right chirality is present in solution. The angle of rotation shows a linear correlation with the analyte concentration, enabling the quantification of enantiomeric ratios in mixtures where the two antipodes are present in solution. This device was successfully used to simultaneously measure different ratios of the enantiomers of 3,4-dihydroxyphenylalanine and tryptophan. The versatility of the proposed approach opens up the possibility to use such a dynamic system as a straightforward (bio)analytical tool for the qualitative and quantitative discrimination of different redox-active chiral probes.
S. Arnaboldi, G. Salinas, G. Bonetti, R. Cirilli, T. Benincori, A. Kuhn
Biosens. Bioelectron. 218 (2022) 114740
Laboratory: ISM

Wireless electromechanical enantio-responsive valves
2022-12-15
Microfluidic valves based on chemically responsive materials have gained considerable attention in recent years. Herein a wireless enantio-responsive valve triggered by bipolar electrochemistry combined with chiral recognition is reported. A conducting polymer actuator functionalized with the enantiomers of an inherently chiral oligomer was used as bipolar valve to cover a tube loaded with a dye, and immersed in a solution containing chiral analytes. When an electric field is applied, the designed actuator shows a reversible cantilever-type deflection, allowing the release of the dye from the reservoir. The tube can be opened and closed by simply switching the polarity of the system. Qualitative results show the successful release of the colorant, driven by chirality and redox reactions occurring at the bipolar valve. The device works well even in the presence of chemically different chiral analytes in the same solution. These systems open up new possibilities in the field of microfluidics, including also controlled drug delivery applications.
G. Salinas, F. Malacarne, G. Bonetti, R. Cirilli, T. Benincori, S. Arnaboldi, A. Kuhn
Chirality (2022) in press
Laboratory: ISM

Self-assembled monolayer protection of chiral-imprinted mesoporous platinum electrodes for highly enantioselective synthesis
2022-12-15
In modern chemistry, chiral (electro)catalysis is a powerful strategy to produce enantiomerically pure compounds (EPC). However, it still struggles with uncontrollable stereochemistry due to side reactions, eventually producing a racemic mixture. To overcome this important challenge, a well-controlled design of chiral catalyst materials is mandatory to produce enantiomers with acceptable purity. In this context, we propose the synergetic combination of two strategies, namely the elaboration of mesoporous Pt films, imprinted with chiral recognition sites, together with the spatially controlled formation of a self-assembled monolayer. Chiral imprinted metals have been previously suggested as electrode materials for enantioselective recognition, separation and synthesis. However, the outermost surface of such electrodes is lacking chiral information and thus leads to unspecific reactions. Functionalising selectively this part of the electrode with a monolayer of organosulfur ligands allows an almost total suppression of undesired side reactions and thus leads to a boost of enantiomeric excess to values of over 90% when using these surfaces in the frame of enantioselective electrosynthesis. In addition, this strategy also decreases the total reaction time by one order of magnitude. The study therefore opens up promising perspectives for the development of heterogeneous enantioselective electrocatalysis strategies.
S. Butcha, V. Lapeyre, C. Wattanakit, A. Kuhn
  Chem.Sci., 13, 2022, 2339
Laboratory: ISM

Two Prizes during JACC2022 conference
2022-10-06
Two prizes were delivered during JACC2022 :
  • Paola Matozzo (Univ. Rennes-PhD student at ISCR) for the poster  prize for her presentation on ''Exciton coupling chirality in helicene-porphyrin conjugates''
  • Nicolas Bruni (Univ. Bordeaux-PhD student at LOMA) for the young talk prize for his presentation on ''Directed morphogenesis of rewritable chiral liquid crystal supramolecular structures by chiral light''
 
Laboratory: JACC2022

GDR PES “Photo-Electro-Stimulation”
2022-10-20
The ISM will host the next symposium of the GDR PES "Photo-Electro-Stimulation". The goal of this GDR is to put together photochemists, spectroscopists and electrochemists to discuss about the interplay between these fields. The forthcoming symposium will take place from Monday 7th to Wednesday 9th of November at the ENSCBP school in Pessac. Here is the website to register: https://jpes.sciencesconf.org/ You should create an account prior to register in case you do not have already one. Registration is free but compulsory !
Laboratory: ISM

INSCRIPTION TO JACC 2022
2022-06-02
Journées André Collet de la Chiralité
  • October 4-7 (2022) in a wonderfull place in Biarritz
  • deadline for oral abstract submission : June 15th July 15-2022
  • deadline for poster abstract submission : August 31, 2022
  • early bird registration starting : July 1rst July 24, 2022
More information on https://jacc2022.sciencesconf.org
With as Plenary and Keynote speakers :
  • Melanie Schnell
  • Tiziana Benincori
  • Marie-Claire Schanne Klein
  • Hiroshi Yamamoto
  • Eric Meggers
  • Etienne Brasselet
  • Mathieu Raynal
  • Benjamin Abécassis
  • Jess Wade
  • Félix Freire
Laboratory: ICMCB

Kick-off meeting of ANR-CHIMERA
2022-05-10
CHIMERA standing for Chiral Induction from Microns to Electrons for Radiative Anisotropy, also in collaboration with Yann Battie (LCP-A2MP-Université de Lorraine/Metz)
Laboratory: IECB/ISM/CELIA/CBMN

Upcoming virtual event for Chirality.
2022-02-17
the  First Virtual Symposium on Chirality hosted by our very own Associate Editor, Prof. Oliver Trapp. The virtual symposium will take place on Tuesday, 22 February 2022 from 12:00 PM UTC to 2:30 PM UTC Register now to attend for free! We welcome three Chirality authors:
  • Prof. Tamaki Nakano (Institute for Catalysis (ICAT), Hokkaido University, Japan)  Light-induced Conformational Transition of Polymers and Small Molecules
    Based on his work:
    Photo racemization of 2,2′-dihydroxy-1,1′-binaphthyl derivatives --- Chirality, 2021. https://doi.org/10.1002/chir.23400
  • Prof. Dr. Alexander Kuhn (Groupe Nanosystèmes Analytiques, Université de Bordeaux, France) Unconventional Electrochemical Approaches for the Direct Readout of Chiral Information
    Based on his work:
    Hybrid light-emitting devices for the straightforward readout of chiral information--Chirality, 2021. https://doi.org/10.1002/chir.23370
  • Dr. Peter Wipf (Department of Chemistry, University of Pittsburgh, USA) Enantioselective Imine Additions in the Preparation of Bioactive Lead Compounds Based on his work: Enantioselective synthesis and selective functionalization of 4-aminotetrahydroquinolines as novel glp-1 secretagogues --Chirality, 2021. https://doi.org/10.1002/chir.23403
More information on our speakers and the agenda for the event can be found on our event website.  
Laboratory: Chirality journal

PhotoElectron ELiptical Dichroism : PEELD
2022-02-09
The resonance-enhanced multiphoton ionization of chiral molecules by elliptically polarized laser pulses produces photoelectron angular distributions that are forward/backward asymmetric with respect to the light propagation axis. We investigate this photoelectron elliptical dichroism in the (2 + 1)-photon ionization of fenchone molecules, using wavelength tunable femtosecond UV pulses. We show that the photoelectron elliptical asymmetry is extremely sensitive to the intermediate resonant states involved in the ionization process, and enables electronic couplings to be revealed that do not show up so clearly when using circularly polarized light.
https://hal-cnrs.archives-ouvertes.fr/hal-03547281
Laboratory: CELIA

Revealing the Influence of Molecular Chirality on Tunnel-Ionization Dynamics
2021-12-21
The tunneling of a particle through a barrier is one of the most fascinating quantum phenomena. The motion taking place under the barrier, in a region forbidden by classical mechanics, is the subject of intense debate. Many experiments aim at measuring the time taken by the particle to go through the tunnel. Here, we take a completely different direction, revealing the influence of the dynamics under the barrier on the motion of the outgoing particle. Our approach combines two key elements: the barrier is chiral—its structure cannot be superimposed on its mirror image—and it rotates in time. Specifically, our barrier holds the electrons inside a chiral molecule, set spinning by a photoionizing laser field whose polarization rotates. The electrons must pass through the spinning barrier of the molecule to escape.
Laboratory: CELIA

Optically Active CdSe/CdS Nanoplatelets Exhibiting Both Circular Dichroism and Circularly Polarized Luminescence
2021-11-30
In this paper, chiroptical 2D CdSe/CdS nanoplatelets (NPLs) are prepared by ligand exchange approach, exhibiting both circular dichroism (CD) and circularly polarized luminescence (CPL). Furthermore, the CD and CPL signals are easily tuned via the design of the CdS-island structuration of the shell and its thickness which are controlled with the reaction time.
Laboratory: ICMCB

Ultrafast relaxation investigated by photoelectron circular dichroism: an isomeric comparison of camphor and fenchone
2021-11-26
Circular dichroism in the photoelectron angular distribution decays exponentially in ∼730 fs from a +9% forward amplitude during the first hundreds of femtoseconds to reach an asymptotic −2% backward amplitude after to have photoexcited at ~6 eV. This time-scale is drastically shorter than in fenchone, its isomer. Our analysis allows us to evaluate the impact of the anisotropy of excitation and reveal a breakdown of the Franck-Condon approximation.
Laboratory: CELIA

Interdisciplinarity and Chirality
2021-10-25
Symmetry and Chirality: Where Physics Shakes Hands with Chemistry and Biology by Laurence Barron
Laboratory: a review article

Direct dynamic read-out of molecular chirality with autonomous enzyme-driven swimmers
2021-10-14
This work describes a first example of autonomous miniaturized swimmers which can detect the chirality of molecules present in solution by adapting their trajectories at the air/water interface. In the presence of one enantiomer they will swimm clockwise, in the presence of the other enantiomer the motion will be anti-clockwise. See also press release by CNRS
Laboratory: ISM

Chirality induction to achiral molecules by silica-coated chiral molecular assemblies
2021-07-23
Hybrid silica-organic nanohelices are used to organize a large variety of non-chiral small organic molecules or inorganic anions to nanometer-sized assemblies. Such chiral organization of achiral molecules induces chiroptical properties as detected by vibrational or electronic circular dichroism (CD), as well as from circularly polarized luminescence (CPL). This is a collaborative work with  University of Rome Tor Vergata and University of Kumamoto
Laboratory: CBMN, ISM

Chirality Induction to CdSe Nanocrystals Self-Organized on Silica Nanohelices: Tuning Chiroptical Properties
2021-10-07
An article on CdSe nanocrystals (NCs) grafted on chiral silica nanoribbons, and the resulting induced circular dichroism observed from the NCs.This work is done in the context of LIA-CNPA by a double degree PhD student between Univ. Bordeaux and Kyoto Univ.
Laboratory: CBMN

Bipolar electrochemical measurement of enantiomeric excess with inherently chiral polymer actuators
2021-07-19
An article about the direct visual readout of enantiomeric excess with wireless actuators. The work has been performed together with collegues from Milan and Como.  
Laboratory: ISM