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As part of an international collaboration, scientists from the Centre de Recherche Paul Pascal, the Institut de Chimie de la Matière Condensée de Bordeaux (CNRS/University of Bordeaux) and the ESRF have shown how to chemically adjust the electronic structure of a layered metal-organic material to control its physical properties, such as electrical conduction and magnetism. This work, published in the journal Nature Communications, paves the way for the design of a new generation of conducting, and potentially superconducting, molecule-based materials.
Molecule-based components proposed for integration into our miniaturized electronic equipment must possess perfectly controlled magnetic and electrical conduction properties. Their ability to be semiconductors, conductors or even insulators, while exhibiting remarkable magnetic properties, makes them very good candidates for integration into future devices for spintronic applications. This is why chemists and physicists are working together to understand the precise role of physicochemical parameters at the origin of the electrical conduction and magnetic properties. With this aim, scientists from more than ten institutions worldwide, led by the Centre de Recherche Paul Pascal (CNRS/University of Bordeaux), studied the coordination materials MCl2(pyrazine)2 (see Figure). These coordination polymers have the particularity to display a layered (2D) structure and to possess strong metal-ligand interactions, which exacerbate the targeted electronic properties. In this family of iso-structural materials, the scientists’ goal was to understand why the vanadium and titanium analogues are an antiferromagnetic insulator and a paramagnetic metal, respectively, while the chromium-based compound is a ferrimagnetic semiconductor.
By combining the analyses of electrical conductivity, magnetoresistance, magnetic properties, specific heat, and density functional calculations (DFT) with the X-ray absorption spectroscopy carried out at the ESRF’s ID12 beamline, the international research teams managed to get a complete picture of the scientific case. “The ID12 beamline is where all questions regarding local magnetic and orbital moments, oxidation state and electronic structures get answers! And if we cannot get an answer right away, we have the chance to modify the experimental setup on the beamline or to imagine new materials to complete the story. What a luxury to work in this unique world-class facility and with its scientists”, explains Rodolphe Clérac, CNRS researcher at the Centre de Recherche Paul Pascal and main corresponding author of the publication. In this published work, the authors show that in the case of vanadium, the pyrazine ligands simply mediate strong interactions between the V(II) spins that remain localized on each metal centre. On the other hand, for titanium, they highlight the transfer of an electron between the Ti(II) ion and the two pyrazine ligands, during the synthesis. For this reason, TiCl2(pyrazine)2 then displays a metallic behavior (a strongly correlated Fermi liquid state), and even presents the highest electrical conductivity ever observed among coordination solids based on octahedrally coordinated metal ions.
“We have a long-standing collaboration with the research team at the Centre de Recherche Paul Pascal and this work is another example of excellent fundamental science combining their methodology with the unique ESRF’s facilities”, says Andrei Rogalev, scientist in charge of ID12.
This work shows how the choice of the metal ion M in a series of iso-structural materials, allows to finely control their physical properties, and in particular their electrical conduction but also their magnetism. Rodolphe Clérac explains the implications of this finding in the long term: “Our results pave the way for the design of a new generation of metal-organic materials possessing metallic or even potentially superconducting properties”.
Structure of the MCl2(pyrazine)2 materials shown perpendicular (a) and parallel (b) to the 2D layers. Color code: V, dark green; Cl, green; N, blue; C, grey. @K. Pedersen & R. Clérac
Reference
Panagiota Perlepe, Itziar Oyarzabal, Laura Voigt, Mariusz Kubus, Daniel N. Woodruff, Sebastian E. Reyes-Lillo, Michael L. Aubrey, Philippe Négrier, Mathieu Rouzières, Fabrice Wilhelm, Andrei Rogalev, Jeffrey B. Neaton, Jeffrey R. Long, Corine Mathonière, Baptiste Vignolle, Kasper S. Pedersenet Rodolphe Clérac
From an antiferromagnetic insulator to a strongly correlated metal in square-lattice MCl2(pyrazine)2 coordination solids
Nature Communications 2022
doi.org/10.1038/s41467-022-33342-5
Contacts
Rodolphe Clérac, CNRS researcher at the CRPP
Email l rodolphe.clerac@u-bordeaux.fr
Find the CNRS interview of Rodolphe Clérac:
Directeur de recherche CNRS au Centre de recherche Paul Pascal (Pessac) et responsable du groupe « Matériaux moléculaires & magnétisme » reçoit le prix « Lectureship in Chemical Sciences » 2022 de la Royal Society of Chemistry, attribué alternativement par la Royal Society of Chemistry et la Société Chimique de France. Cette distinction récompense ses développements de nouveaux domaines de recherche en magnétisme moléculaire et ses contributions originales à l’étude des matériaux magnétiques.
The Royal Society of Chemistry-Société Chimique de France Lectureship in Chemical Sciences is a reciprocal lectureship awarded alternately by the Royal Society of Chemistry and the Société Chimique de France (SCF), for advances in chemistry made by a scientist while working and residing in France or the UK, respectively.
Dr. Clérac’s team build matter from the atomic level using metals and organic molecules in order to organise them to promote one or several targeted physical properties. This requires a strong synergy between the chemistry and physics of these systems. It is this duality that fascinates Rodolphe Clérac and inspires his research work on molecule-based magnetic materials and molecular magnets. His group’s work offers broad prospects for the preparation of a new generation of lightweight magnetic materials that could be applied within aeronautics, space or mobile technologies and the electronics of tomorrow….
Congratulations to Pierre Dechambenoit appointed as 2022 junior member of the Institut Universitaire de France.
Congratulations to Ryan Evenson (Harvard University) and Carmen Metzler (University of Puerto Rico), both recipients of a 2022-23 Chateaubriand Fellowship (http://chateaubriand-fellowship.org). They will spend 4 months in the M3 team working on magnetic materials.
ADAGIO is an international fellowship programme aiming at attracting talented post-doc scientists to develop their 3 year projects.
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During more than 7 minutes, this TV report shows the work of our team through different short videos and by interviewing Rodolphe Clérac. The main topics are coordination chemistry, our research work, the CNRS 2021 silver medal, the importance of fundamental research and research funding in France.
Ces pros qui nous inspirent : dans ce rendez-vous hebdomadaire, on découvre les coulisses du monde du travail en Nouvelle-Aquitaine, on comprend les problématiques des entreprises, leurs innovations, et leur agilité dans un monde en pleine mutation.
TV7 : Modes d’Emplois / Chimie de coordination : du temps pour la recherche
Épisode du 17/02/2022
Les acènes sont des molécules linéaires composées de cycles de benzène fusionnés, dont l’extension améliore les performances électroniques, mais complique fortement la synthèse. Des scientifiques du CEMES (CNRS), de l’académie tchèque des sciences (République tchèque) et de l’université d’Hokkaido (Japon) ont obtenu le premier acène stable à neuf cycles benzéniques : le nonacène. Publiés dans la revue Nature Communications, ces travaux pourraient aboutir au développement de nouveaux composants électroniques.
Les acènes sont une famille d’hydrocarbures comprenant plusieurs benzènes fusionnés formant une chaîne linéaire. Ces molécules présentent des propriétés électroniques singulières, car plus ces acènes sont longs et plus leur comportement se rapproche de celui des semi-métaux. Or, comme il s’agit de molécules organiques, les acènes sont beaucoup plus faciles à fonctionnaliser et mettre en forme que les semiconducteurs inorganiques, ce qui permet de leur donner des propriétés supplémentaires et de les déposer sur davantage de surfaces différentes. Les chercheurs tentent donc de concevoir des acènes de plus en plus longs, mais l’ajout de nouveaux cycles benzéniques réduit très fortement la solubilité et la stabilité de la molécule. Si la fabrication du tétracène ou du pentacène, composés respectivement de quatre et cinq cycles de benzène, est bien connue, des doutes subsistaient quant à la possibilité d’aller au-delà de l’heptacène (sept cycles). Des chercheurs du Centre d’élaboration de matériaux et d’études structurales (CEMES, CNRS), de l’académie tchèque des sciences (République tchèque) et de l’université d’Hokkaido (Japon) ont obtenu pour la première fois un nonacène, soit un acène à neuf cycles. Il se présente sous la forme d’un solide noir, qui se conserve sous atmosphère inerte pendant des mois…
By coupling together a pair of lanthanide ions within the same compound, researchers have created what they believe are the most magnetic molecules ever made (Science 2022, DOI: 10.1126/science.abl5470).
“By all the traditional metrics of single-molecule magnets, they’re the best,” says Nicholas Chilton of the new molecules. Chilton, who’s based at the University of Manchester, collaborated on the work with Jeffrey Long at the University of California, Berkeley, and Benjamin Harvey at the US Naval Air Warfare Center Weapons Division. Although the molecules’ magnetism only reveals itself at low temperatures, Chilton hopes that these dilanthanide complexes might pave the way for new types of powerful yet lightweight permanent magnets.
Roberta Sessoli of the University of Florence, a pioneer of single-molecule magnets who was not involved in the work, says “this really is a very, very important piece of work. This is something that is going to remain as a milestone.”…
Metal-containing organic molecules that exhibit magnetism could one day offer a lightweight, flexible alternative to the relatively dense metal and ceramic magnets used in today’s engines, turbines, and electronics. Researchers have shown that a promising but unstable molecular magnet can become stable when 3D printed (Nano Lett. 2022, DOI: 10.1021/acs.nanolett.1c01879).
In recent years, chemists have built molecular magnets that have magnetic fields comparable to those of conventional magnets at room temperature. But even promising ones, such as vanadium hexacyanochromate, remain sensitive to the environment, says Shenqiang Ren, a materials scientist at the University at Buffalo. “You have to test them in a glove box,” he says. Ren wanted to mix a molecular magnet with a printing resin with the hope that the plastic casing might protect the material from the open air.
Rodolphe Clérac, chercheur en chimie de coordination au Centre de recherche Paul Pascal (CRPP – CNRS et Université de Bordeaux ) nous parle de son projet de recherche ! Il est lauréat 2021 de la médaille d’argent du CNRS pour son travail sur la physique et la chimie des matériaux moléculaires magnétiques
Pour faire face aux besoins croissants en stockage de données informatiques les chimistes sont parvenus à stocker l’information binaire à l’échelle de molécules individuelles appelées « molécules-aimants ». Cependant, pour envisager leur insertion au sein de dispositifs, les molécules doivent pouvoir conserver l’information sans subir l’influence de celle portée par les voisines, ce qui nécessite de contrôler leur organisation au sein du matériau. Défi relevé par des scientifiques du Centre de recherche Paul Pascal (CNRS / Université de Bordeaux) et de l’Université de Canterbury en Nouvelle-Zélande qui montrent comment des caténanes magnétiques, structures mécaniquement imbriquées, permettent cette organisation de molécules-aimants au sein d’édifices complexes tridimensionnels. Ces résultats font l’objet d’une publication dans la revue Angewandte Chemie.
Comme son nom l’indique, une molécule-aimant est un aimant formé d’une seule molécule. Sous l’action d’un champ magnétique, son aimantation peut présenter deux états adressables. Il est possible de passer réversiblement d’un état à l’autre ce qui confère à cette molécule-aimant un effet mémoire. D’où l’intérêt des spécialistes du magnétisme moléculaire pour ces objets qui pourraient permettre dans le futur le stockage d’information binaire, voire quantique, à une échelle très réduite.
Au sein d’un même matériau ou d’un dispositif de stockage, chaque molécule-aimant doit être capable de conserver son état magnétique sans subir l’influence de celle de ses voisines, condition essentielle si l’on veut contrôler l’information stockée sur chaque molécule. Il est donc nécessaire de maîtriser leur organisation de manière à ce que l’on puisse assigner individuellement un bit d’information à une molécule-aimant donnée.
Aujourd’hui, on sait isoler les molécules-aimants les unes des autres en les déposant sur des surfaces. Mais, pour parvenir à une miniaturisation plus importante encore, il faut dépasser cet arrangement bidimensionnel pour atteindre une organisation tridimensionnelle, avec un contrôle parfait de l’arrangement des molécules dans les trois directions de l’espace.
Grâce à la flexibilité de la chimie de coordination,* des scientifiques du Centre de recherche Paul Pascal (CNRS / Université de Bordeaux) et de l’Université de Canterbury en Nouvelle-Zélande viennent de démontrer qu’il est possible d’organiser des molécules-aimants dans des constructions moléculaires d’une grande complexité, comme un caténane** résultant de l’auto-assemblage de 8 molécules-aimants à base d’ions cobalt(II). Cette architecture complexe en catenane présente deux carrés imbriqués l’un dans l’autre dont chaque sommet est une molécule-aimant isolée de ses voisines (figure ci-dessus). On peut donc penser que dans le futur, les chimistes de coordination pourront réellement répondre à n’importe quel type d’organisation nécessaire aux applications des molécules-aimants….
Related links:
Angewandte Chemie International Edition: https://doi.org/10.1002/anie.202113837
Websites:
Congratulations to all the speakers!
The 20 minutes website has also communicated on our article in The Conversation.
Des aimants légers et performants grâce à la chimie moléculaire…
Les aimants sont des matériaux présents dans de très nombreux objets de nos vies quotidiennes: ce sont par exemple des constituants essentiels de nos ordinateurs, des microphones, des moteurs électriques d’appareils ménagers ou même de turbines d’éoliennes. Pour certaines applications, comme dans les smartphones ou les satellites, ces aimants doivent être à la fois légers et de petite taille.
Les aimants sont généralement des solides constitués de métaux purs, d’oxydes métalliques ou d’alliages métalliques. Malgré leur utilisation intensive et leur énorme succès dans les applications technologiques, la production d’aimants pose des problèmes environnementaux et économiques. Certains éléments chimiques nécessaires à leur élaboration, comme les terres rares présents dans les aimants les plus puissants connus aujourd’hui, sont inégalement répartis sur la planète ou difficiles à isoler. De plus, la fabrication des aimants nécessite souvent des procédés réalisés à haute température qui consomment beaucoup d’énergie.
Afin de remédier à ces problèmes, les scientifiques essayent depuis environ 3 décennies de créer un nouveau type d’aimants en assemblant des molécules pour créer un édifice aux propriétés désirées. L’élaboration de tels assemblages moléculaires se fait à température ambiante, ce qui rend leur fabrication facile à reproduire et peu coûteuse. Cependant, il y a encore quelques mois, les performances des aimants moléculaires (température de fonctionnement, capacité d’attraction…) étaient encore très loin de celles des aimants conventionnels.
Récemment, dans une étude publiée dans Science, nous avons démontré qu’il est désormais possible d’obtenir des aimants moléculaires avec des caractéristiques comparables aux aimants conventionnels….
Rodolphe Clérac, Research Director at the Centre de Recherche Paul and head of the “Molecular Materials & Magnetism” team, received the 2021 Silver Medal from the CNRS. In 2000, he joined the IUT of Bordeaux 1 and the Centre de Recherche Paul Pascal, as an associate professor. He began his career focusing on the physical properties of fullerene salts and new molecular materials. In 2001, he brought together a new research team around molecular magnetic materials and introduced coordination chemistry at the Centre de Recherche Paul Pascal.
In 2002, he discovered the first single-chain magnets, which opened up a new research field in molecular magnetism. His work then focused on these new one-dimensional magnets, the organization of molecule-magnets into coordination networks and he widened his researches towards bi- and tri-stable molecule-based systems with intramolecular electron transfer or spin conversion in solution, in the solid state or liquid crystal phases. In 2008, he joined the CNRS becoming a full-time researcher, and then in 2013, he was promoted to research director. In 2020, he developed a new post-synthetic approach and obtain the first molecular magnets operating up to 242°C with a high coercivity at room temperature. This synthetic strategy offers broad prospects for the preparation of a new generation of lightweight magnets at high temperature. His projects are currently directed towards the synthesis of new multifunctional molecule-based materials containing redox-active sites in order to obtain high-performance magnets also possessing high electrical conduction, photoactivity or porosity allowing selective gas absorption.
Rodolphe Clérac is author and co-author of over 500 publications and has presented over 130 invited lectures. He was elected in 2019 to the European Academy of Sciences and in 2020 to the Academia Europaea. In 2014, he became a junior distinguished member of the Société Chimique de France and received various awards including in 2017 the France-Berkeley Fund Award, in 2014 the National Chinese Award for the “1000 Talents Program” and in 2009 the Young Researcher Award of the Division de Chimie Physique de la Société Chimique de France.
Contact: Rodolphe Clérac
Centre de Recherche Paul Pascal, UMR CNRS 5031
“Molecular Materials & Magnetism” team
115 Avenue du Dr. A. Schweitzer, 33600 Pessac, FRANCE
Phone: +33 (0) 5 56 84 56 50
“Substantial π-aromaticity in the anionic heavy-metal cluster [Th@Bi12]4−“, A.R. Eulenstein, Y.J. Franzke, N. Lichtenberger, R.J. Wilson, H. Lars Deubner, F. Kraus, R. Clérac, F. Weigend and S. Dehnen, Nature Chemistry, 13, 149-155, (2021) – 10.1038/s41557-020-00592-z – hal-03133022
See below different links, which discuss this work:
In English:
https://chemistrycommunity.nature.com/
https://www.chemistryworld.com
In German:
“Metal-organic magnets with large coercivity and ordering temperatures up to 242°C”, Science, Vol. 370, Issue 6516, pp. 587-592, (2020) – 10.1126/science.abb3861 – Abstract – Reprint – Full text
“Lightening the load” by Jake Yeston – 10.1126/science.370.6516.543-e
“A hard permanent magnet through molecular design” by R. A. Murphy, J. R. Long & T. D. Harris, Communications Chemistry (2021) 4:70 – link
“Des aimants légers et performants grâce à la chimie moléculaire” by C. Mathonière and R. Clérac, The Conversation, 11th April 2021 – link
See below other links (179), which discuss our work (in 19 different languages):
In French (17):
- Communiqué de Presse du CNRS
- France culture interview of R. Clérac
- 20minutes.fr
- École Normale Supérieure (Chimie)
- Lab. Ondes et Matière d’Aquitaine
- Centre de Recherche Paul Pascal
- Techniques de l’Ingénieur
- Nextinpact.com
- Industrie-techno.com
- Knowledi.com
- Enviscope.com
- Genius-science.fr
- Techno-science.net
- Maniacgeek.net
- Technoguide.fr
- Citizenside.fr
- Rtflash.fr
In Greek:
In Basque (3):
In Spanish (21):
- Ebuenasnoticias.com
- Lavanguardia.com
- Enciclopediauniverso.com
- Tn.com.ar
- 15minutos.com
- Eluniversal.com.mx
- Enterateaguascalientes.com
- Noticiasdelaciencia.com
- Planoinformativo.com
- Noticiasncc.com
- Towla24.com
- Ehu.eus
- Zientzia-astea.org
- Sitiosfuente.info
- Quimica.es
- Pdm.com.co
- Esdelatino.com
- Nuevoperiodico.com
- newsupdater.xyz: pages 1 & 2
- servepink.com
In German (6):
- Weltderphysik.de
- Chemie.de
- Frankfurter Allgemeine
- Wissenschaft-aktuell.de
- Wirtschaftsblatt-bg.com pages 1 & 2
In Chinese (17):
- Cnfeol.com
- Mp.weixin.qq.com
- 68nw.com
- News.xsjk.net
- Repe.com.cn
- Szdwzr.com
- Read01.com
- M.nanoer.net
- yidianzixun.com
- sohu.com
- dy.163.com
- 360doc.com
- zhuanlan.zhihu.com
- baijiahao.baidu.com
- fjirsm.ac.cn
- 519640.com
- min.news
In Japanese:
In Indonesian (3):
In Hungarian:
In Thai:
In Vietnamese:
In Persian:
In Romanian (2):
- Riotech.xyz: pages 1 & 2
In English (60):
- CNRS News
- The European Synchrotron Radiation Facility (ESRF) News
- Physicsworld
- Eurekalert.org: pages 1 & 2
- University of Bath (UK)
- The University of Jyväskylä (Finland)
- Relatablesci.com
- Qsstudy.com
- Ksc.krasn.ru
- En.brinkwire.com
- Scitechdaily.com: pages 1 & 2
- Azom.com
- Sciencedaily.com: pages 1 & 2
- Losangelesweeklytimes.com
- Thesciencestory.com
- Helabima.uk
- Marketresearchstore.com
- 7thspace.com
- Scienmag.com
- Bioengineer.org
- Alphagalileo.org
- Spaceforce.org.uk
- Occasion-to-be.com
- News.nestia.com
- Chemeurope.com
- Phys.org
- Knowledia.com
- Ioherald.com
- Todaynewspost.com
- Dagoldinfo.com
- Innovations-report.com
- Archyde.com
- 24x7news.live
- Rejerusalem.com
- Severskiy.com
- Farsnews.ir
- Upnewsinfo.com
- Wtbgoods.com
- Rokzfast.com
- Haptic.ro
- Newonnews.com
- Dailynewsbro.com
- Amazingresearchs.com: pages 1 & 2
- Newsdelay.com: pages 1 & 2
- Latestnewstripura.com
- Healthmedicinet.com
- Sciencecodex.com
- Nextbizpost.com
- Hindikhabre.com
- Svmakers.org
- Thescotfree.com
- Networthynewz.com
- Climaxnewsroom.com
- Focustechnica.com
- Alternative-learning.org
In Russian: (23)
- Kirensky.ru: pages 1 & 2
- Sib-science.info
- Scientificrussia.ru
- Ksc.krasn.ru
- News.rambler.ru
- Polit.ru
- anonsens.ru
- Sbras.info
- 24rus.ru
- Nauka.tass.ru
- Sensaciy.net
- Indicator.ru
- News.mail.ru
- Yandex.ru
- 1line.info
- Openscience.news
- Nanonewsnet.ru
- zavtranews.ru
- glasnarod.ru
- minobrnauki.gov.ru
- ko.com.ua
- technews2.pp.ua
In Filipino (2):
- Healthie.xyz: pages 1 & 2
In Lithuanian (2):
- Maketrendz.xyz: pages 1 & 2
In Finnish (2):
In Czech (2):
- Instantz.xyz: pages 1 & 2
Towards next-generation molecule-based magnets
Magnets are to be found everywhere in our daily lives, whether in satellites, telephones or on fridge doors. However, they are made up of heavy inorganic materials whose component elements are, in some cases, of limited availability.
Now, researchers from the CNRS, the University of Bordeaux and the ESRF (European Synchrotron Radiation Facility in Grenoble) have developed a new lightweight molecule-based magnet, produced at low temperatures, and exhibiting unprecedented magnetic properties. This compound, derived from coordination chemistry, contains chromium, an abundant metal, and inexpensive organic molecules. This is the first molecule-based magnet that exhibits a ‘memory effect’ (i.e. it is capable of maintaining one of its two magnetic states) up to a temperature of 240°C. This effect is measured by what is known as a coercive field, which is 25 times higher at room temperature for this novel material than for the most efficient of its molecule-based predecessors. This property therefore compares well with that of certain purely inorganic commercial magnets. The discovery, published on 30 October in Science, opens up highly promising prospects, which could lead to next-generation magnets complementary to current systems.
Reference & authors: P. Perlepe, I. Oyarzabal, A. Mailman, M. Yquel, M. Platunov, I. Dovgaliuk, M. Rouzières, P. Négrier, D. Mondieig, E. A. Suturina, M.A. Dourges, S. Bonhommeau, R. A. Musgrave, K. S. Pedersen, D. Chernyshov, F. Wilhelm, A. Rogalev, C. Mathonière, R. Clérac, “Metal-organic magnets with large coercivity and ordering temperatures up to 242°C”, Science, Vol. 370, Issue 6516, pp. 587-592, (2020) – 10.1126/science.abb3861 – Abstract – Reprint – Full text
Online comments and publications
Acknowledgments: This work was supported by the University of Bordeaux, the Région Nouvelle Aquitaine, Quantum Matter Bordeaux, the Basque Government, the University of the Basque Country, the Villum Fonden, the University of Jyväskylä, the Academy of Finland, the Centre National de la Recherche Scientifique (CNRS) and the ESRF-The European Synchrotron.
Contact: clerac@crpp-bordeaux.cnrs.fr
What is the Academia Europaea?
The object of Academia Europaea is the advancement and propagation of excellence in scholarship in the humanities, law, the economic, social, and political sciences, mathematics, medicine, and all branches of natural and technological sciences anywhere in the world for the public benefit and for the advancement of the education of the public of all ages in the aforesaid subjects in Europe.
Academia Europaea is a European, non-governmental association acting as an Academy. Our members are scientists and scholars who collectively aim to promote learning, education and research. Founded in 1988, with about 3800 members which includes leading experts from the physical sciences and technology, biological sciences and medicine, mathematics, the letters and humanities, social and cognitive sciences, economics and the law.
This study reports the first transition metal compounds featuring mixed fluoride–cyanide ligands. A significant enhancement of the magnetic anisotropy, as compared to the pure fluoride ligated compounds, is demonstrated by combined analysis of high-field electron paramagnetic resonance (HF-EPR) spectroscopy and magnetization measurements.
What did scientists discover?
This study reports the first transition metal molecules featuring both fluorine and cyanide ligands (see “branches” attached to the metal atom (M) in the molecules at the top of the figure). A strong and significant enhancement of the non-uniformity of the magnetism, the “magnetic anisotropy” for the trans-[ReIVF4(CN)2]2– complex (shown in the upper right) was discovered by combined high-field magnetization and electron paramagnetic resonance (EPR) spectroscopy (see lower Figure).
Why is this important?
This research highlights an efficient new strategy for synthesizing molecular building blocks based on heavier transition metals that feature relatively large magnetic moments and very strong magnetic anisotropy. Such building blocks may form the basis for future high-performance magnetic materials used in high-density information storage applications.
Read more on MagLab website:
About the European Academy of Sciences (EURASC) :
“The European Academy of Sciences (EURASC) is a non-profit non-governmental, independent organization of the most distinguished scholars and engineers performing forefront research and the development of advanced technologies, united by a commitment to promoting science and technology and their essential roles in fostering social and economic development. One of the most important objectives of the Academy is the promotion of fundamental research and excellence in science and technology. The EURASC aims to recognize and elect to its membership the best European scientists with a vision for Europe as a whole, transcending national borders both in elections and in actions, and with the aims of strengthening European science and scientific cooperation and of utilizing the expertise of its members in advising other European bodies in the betterment of European research, technological application and social development.”
https://www.eurasc.org/new-members
https://www.eurasc.org/user/725/rod…
Contact :
Centre de Recherche Paul Pascal, UMR CNRS 5031
115 Avenue Schweitzer, 33600 Pessac, FRANCE
Phone : +33 (0) 5 56 84 56 50
Dr. Xiaozhou Ma received one of two prizes for the best poster presented at the 7th European Conference on Molecular Magnetism which took place in Florence, Italy, the 15th-18th of September 2019.
The title of her poster was “Magnetic Exchange Coupling Promotion in Dinuclear Compounds with Redox-active Ligand”.
Xiaozhou Ma was a PhD student of P. Dechambenoit and R. Clérac who defended on the 11th of September 2019.
Rodolphe Clérac’s research has been recently cited by the CNRS Institute of Chemistry.
L’origine du magnétisme atypique de l’ion actinide Uranium(IV) enfin comprise
Les ions de terres rares et d’actinides, qui présentent des propriétés magnétiques remarquables étant données leurs structures électroniques, sont de bons candidats pour entrer dans la composition des aimants de nouvelle génération. Mais alors pourquoi, de manière atypique, l’uranium au degré oxydation IV n’est que faiblement magnétique, alors qu’au regard de sa structure électronique, ses propriétés devraient être comparables aux autres analogues de terres rares ou d’actinides?
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In partial fulfillment of the requirements for a posthumous PhD diploma for Angela Valentin, a thesis defense of her work will take place in the CRPP amphitheatre on 11 December 2019 at 14h.
In attendance will be the jury consisting of Jeanne Crassous (Institut des Sciences Chimiques de Rennes), Lorenzo di Bari (University of Pisa), Jérôme Lacour (Univeristy of Geneva), and Cécile Zakri (University of Bordeaux).
The presentation will be delivered by E. Hillard and P. Rosa..
Friends and family are cordially invited to attend this commemoration of Angela’s work.
Dans le cadre de l’Idex de l’Université de Bordeaux, Guillaume Naulet, a reçu le prix de thèse “Sciences et Technologie”.
Guillaume a effectué sa thèse au CRPP de 2015 à 2018, sous la direction de Fabien DUROLA et Harald BOCK, dans l’équipe M3.
Son travail concernait le développement de techniques de protection pour la synthèse de larges arènes polycycliques par réaction de Perkin, ce qui a notamment permis de former des rubans de Möbius moléculaires.
Des molécules aromatiques et torsadées
“La chimie organique est régie par de nombreuses règles
établies au fil des expériences. Aujourd’hui, les chimistes
explorent les limites de ces lois. Comme Fabien Durola et son
équipe du Centre de recherche Paul Pascal (CNRS/Université
de Bordeaux), qui prouvent avec leur cyclo-tris-[5]hélicène
qu’un composé aromatique peut être triplement torsadé,
esthétique et atypique, de par ses propriétés électroniques
induites.”
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The Magnetism Network of the Greater Region won the 2018 interregional research prize for its collaborative fundamental research and R&D activities. Congratulations to the coordinator of this organizion, Thomas Hauet. Let’s wish the same success to the French and European Magnetometry Network!
This work demonstrates the possibility of modulating the spin state of the FeII sites and subsequently the magnetic properties of a [2×2] FeII grid-like complex by variation of the degree of deprotonation of the hydrazine-based N-H sites of the ligand in the complex. Evidence has been provided, both in the solid state and in solution, towards understanding the strong influence of the spin-crossover process on the pKas of the grid ligands, which exhibit a unique deprotonation pattern. The present study provides a demonstration of the effect of spin state switching of a chemical property, here on ligand pKa in a metallosupramolecular grid.
![modulating the spin state of the FeII sites and subsequently the magnetic properties of a [2x2] FeII grid-like complex](https://sites.google.com/site/m3researchgroup/News/newpublicationinthejournaloftheamericanchemicalsocietyonspinstatechemistry/TOC.fr.jpg?attredirects=0)
Sébastien Dhers, Abhishake Mondal, David Aguilà, Juan Ramírez, Sergi Vela, Pierre Dechambenoit, Mathieu Rouzières, Jonathan R. Nitschke, Rodolphe Clérac & Jean-Marie Lehn. Spin State Chemistry: Modulation of Ligand pKa by Spin State Switching in a [2×2] Iron(II) Grid-Type Complex J. Am. Chem. Soc. 2018, 140 (26), pp 8218–8227 DOI : 10.1021/jacs.8b03735
Incorporating functional molecules into sensor devices is an emerging area in molecular electronics that aims at exploiting the sensitivity of different molecules to their environment and turning it into an electrical signal. Among the emergent and integrated sensors, microelectromechanical systems (MEMS) are promising for their extreme sensitivity to mechanical events. However, to bring new functions to these devices, the functionalization of their surface with molecules is required. Herein, we present original electronic devices made of an organic microelectromechanical resonator functionalized with switchable magnetic molecules. The change of their mechanical properties and geometry induced by the switching of their magnetic state at a molecular level alters the device’s dynamical behavior, resulting in a change of the resonance frequency. We demonstrate that these devices can be operated to sense light or thermal excitation. Moreover, thanks to the collective interaction of the switchable molecules, the device behaves as a non-volatile memory. Our results open up broad prospects of new flexible photo- and thermo-active hybrid devices for molecule-based data storage and sensors.
Matias Urdampilleta, Cedric Ayela,
Pierre-Henri Ducrot, Daniel Rosario-Amorin, Abhishake Mondal, Mathieu
Rouzières, Pierre Dechambenoit, Corine Mathonière, Fabrice Mathieu, Isabelle
Dufour et Rodolphe Clérac
Molecule-based microelectromechanical sensors
Scientific Reports – Mai 2018
DOI: 10.1038/s41598-018-26076-2
Stephanie Beach, of the Doerrer Group (Boston University), recently won a prestigious Chateaubriand Fellowship. The Chateaubriand Fellowship is a grant offered by the Embassy of France in the United States. It supports outstanding Ph.D. students from American universities who wish to conduct research in France for a period ranging from 4 to 9 months. Chateaubriand fellows are selected through a merit-based competition, through a collaborative process involving expert evaluators in both countries.
The program is divided into two subprograms: Humanities and Social Sciences (HSS) which supports those who seek to study Humanities and Social Sciences. Stephanie was awarded the Chateaubriand Fellowship in Science, Technology, Engineering, Mathematics & Biology-Health (STEM), which is for doctoral students who aim to initiate or reinforce collaborations, partnerships or joint projects between French and American research teams. This fellowship is offered by the Office for Science & Technology (OST) of the Embassy of France in partnership with American universities and French research organizations such as CNRS, Inserm and Inria.
Stephanie is currently working at the Centre de Recherche Paul Pascal, a CNRS lab, in Bordeaux, France from February through May of 2018 to partner with the group of Prof. Rodolphe Clérac. She is developing new variations of the Doerrer group thiocarboxylate lantern complexes for development as single molecule magnets.
Congratulations Stephanie!
Past news:
- Rodolphe Clérac has been selected for the France-Berkeley Fund Award
- First circular for the ECMM
- First circular for the BOOK-D
- Emergent properties in spin crossover materials
- Fabien Durola, Jean-Marie Lehn and Jean-Pierre Sauvage on the 2016 Nobel Prize in Chemistry
- Benjamin Wilson awarded 2016 NZ France Friendship Fund Excellence Scholarship
- Abhishake Mondal wins the European Award on Molecular Magnetism Doctoral Thesis
- CNRS INC Focus on Molecular Magnet…
- M3 work on SMM featured in C&EN
- Congratulations Anandi!
- Kasper won a prize from Dalton Poster Symposium.
- M3 work on molecular switch cited by the CNRS INC
- R. Clérac honored by the SCF
- CNRS INC is talking about M3 work on tristable SMM !
- M3 research on Redox-Active ligand to promote spin delocalization cited by the CNRS INC
- The biggest polyaromatic “seen” by XRD…
- CNRS focus on molecular switch from M3…
- Ie-Rang Jeon wins thesis prize