Molecular magnetism
The Molecular Magnetism team develops a research activity on complex magnetic structures involving metal ions and/or radicals. It is based on two complementary axes:
- The study of the electronic structure of synthetic molecules or biological systems by electron paramagnetic resonance (EPR) at high field and high frequency (HF-EPR). Such studies mainly focus on the determination of magnetic anisotropy and the understanding of its origin. They also involve, in the most favorable cases, the study of their relaxation properties.
- The synthesis and caracterization of metal complexes with remarkable magnetic properties and/or original properties. The synthesis activity uses both techniques from organic chemistry (synthesis of complex proligands) and coordination chemistry. The characterization is essentially based on classical spectroscopies, single-crystal X-ray diffraction and magnetometry.
Self-Assembly of 2p-3d-4f molecular clusters (adapted from Inorg. Chem. 2022, 61, 17037–17048)
Research staff
Non-permanent researchers who have worked in or passed through the laboratory :
Petr Neugebauer, Varun Kumar, Guillaume Perrin-Toinin
Topics
Determining the magnetic anisotropy of molecular systems :
The magnetic anisotropy of discrete molecular systems is the essential characteristic for the appearance of molecule-magnet properties.
The LNCMI offers precise determination of anisotropy parameters using a multi-technique approach that combines experimental methods such as High-Field High-Frequency Electron Paramagnetic Resonance (HF-EPR), magnetometry and, where appropriate, magneto-Infrared spectroscopy, with a theoretical approach, usually in the context of collaborations.
Metal-radical architectures :
The design and synthesis of molecular magnetic materials has been the subject of intense research over the last 20 years, mainly using transition metals or lanthanide ions linked by diamagnetic ligands. However, the use of open-layer organic ligands offers several advantages. The first of these is the possibility of intense metal-radical exchange interactions. This was first demonstrated with nitronyl nitroxide radicals.
We’re interested in another family of radicals, verdazyl radicals. These radicals cannot be coordinated to metal ions in a monodentate fashion. In order to take advantage of the chelate effect, it is necessary to introduce ancillary coordinating groups to control denticity or even introduce new functions (bridging, chirality, etc.). Finally, verdazyl radicals can be oxidized and/or reduced, which is sometimes a weakness in terms of stability, but also opens up new possibilities for controlling exchange interactions, for example.
Architectures combining metal ions and organic radicals are a novel approach to a number of fundamental questions in molecular magnetism, such as the respective roles of the metal ion’s localized spin and the ligand’s delocalized spin, the influence of the radical ligand on the spin transition, and total spin parity on molecule-magnet properties.
Complex with three cobalt(II) ions coordinated by acetate bridges and verdazyl ligands (Inorg. Chem. 2022, 61, 17037–17048).
Techniques
High-Field High-Frequency Electronic Paramagnetic Resonance (HF-EPR)
Chemistry Laboratory
The LNCMI is equipped with a chemistry laboratory covering the main synthesis methods used in molecular chemistry, with facilities for synthesis in controlled atmospheres (vacuum ramps, glove boxes) or under solvothermal conditions, for example. The laboratory also boasts a wide range of characterization techniques, including IR and ATG (with the possibility of coupling the two techniques), UV-Vis spectroscopy (absorption and circular dichroism) and electrochemistry.
Publications
Selected publications
Investigation by Chemical Substitution within 2p-3d-4f Clusters of the Cobalt(II) Role in the Magnetic Behavior of [vdCoLn]2 (vd = Verdazyl Radical)
G. Novitchi, S. Shova, C. Train,
Inorg. Chem. 2022, 61, 17037–17048 (HAL)
Chemical tuning of spin clock transitions in molecular monomers based on nuclear spin-free Ni(II)
M. Rubín-Osanz , F. Lambert , F. Shao , E. Rivière , R. Guillot , N. Suaud, N. Guihéry, D. Zueco , A.-L. Barra, T. Mallah , F. Luis
Chem. Sci. 2021, 12, 5123-5133 (HAL)
Macroscopic and Microscopic Magnetic Investigation of an Atypical 3D Bimetallic Oxalate- Based Magnet
V. Simonet, F. Damay, S. Ferlay, A. Cea, C. Maxim, C. Train
J. Phys. Chem. C 2020, 124, 1, 952-957J. Phys. Chem. C 2020, 124, 1, 952-957 (HAL)
Publications LNCMI de la thématique sur HAL