The research activity of the team is focused on electron spin resonance in high field and high frequency (HF-EPR) and synthesis of molecule-based magnetic materials.
For the HF-EPR, the effects related to high field can usually be distinguished from those associated with high frequency :
The main interest for using high fields concerns systems that have a X band signal. These studies focus on systems with spin S = 1/2. They allow measuring differences in Landé factors masked at low-field system by either excessive linewidths, or field-independent interactions such as hyperfine ones.
The high frequency measurements mainly applies to the study of the so-called ‘X-band silent’ compounds, that is to say to compounds with integer spin and/or large zero-field splitting (ZFS). The development of EPR spectrometers using high frequencies (95 GHz and above) in fact led to the disappearance of the concept of EPR silent compound.
The synthesis of molecular magnetic materials is mainly developed along two axes that shall feed one another :
The synthesis and study of multifunctional metal-organic frameworks. It is based on the versatility of molecular chemistry. It indeed allows, by an appropriate choice of the starting precursors, to obtain materials combining several physico-chemical properties in a rational way. In the most interesting cases, these properties interact to give rise to new physico-chemical properties. Our efforts are currently orientated towards compounds combining magnetism and properties associated with non-centrosymmetry. A special focus is given to magneto-chiral dichroism, a property that exists in enantioenriched systems exhibiting a spontaneous or induced magnetization.
The synthesis and study of magnetic materials based on verdazyl radical. These organic species give birth to purely organic compounds of interest but are also the source for developing an original coordination chemistry towards transition and lanthanide ions. It leads to compounds where the exchange interaction can be very strong and/or sigle-molecule magnets behaviour as observed in a series of clusters combining combining verdazyl radicals, transition metal(II) and lanthanide(III) ions.
Moreover we are currently developing set-ups to perform electrochemical and chemical reactions under high magnetic fields. Promising preliminary results have been obtained : (i) working in the same conditions (reactants, solvent, temperature,…) with and without magnetic fields, different crystallographic phases of a molecular conductors were obtained (ii) the kinetics of a reaction catalyzed by transition metal complexes with non-innocent ligands is deeply influenced by the application of a magnetic field.
More details can be found below: