OMC team - Multifunctional Inorganic Materials

The Multifunctional Inorganic Materials (MIM) group involves eight permanent researchers who are molecular chemists, crystallographers and physicists with knowledges in transition and rare earth metals coordination chemistry. Our common aim is the rational design of molecules and materials using step by step synthetic approaches. The main specificity of the MIM group research activity is the combination of electronic, (nonlinear) optical and magnetic properties. The backgrounds, working environment and collaborations of the MIM group makes it an ideal research group for the study of multidisciplinary research projects with high attractiveness level for all the students.

Multiple Properties Single-Molecule Magnets

Keywords: Single-Molecule Magnet, Luminescence, Chirality, Electro-activity

The design of multifunctional materials is a challenge for both chemist and physicist communities eager to know and observe new physical properties resulting from the synergy of others properties. Thus the elaboration of lanthanide luminescent Single-Molecule Magnets allow magneto-structural correlations between magnetism and luminescence since the latter is a photography of the energy splitting at the origin of the magnetic behavior. The introduction of chirality through the use of binaphtyl or helicenes based-ligands induced a differentiation of magnetic behavior between the racemic mixture and the enantiomeric form of the molecular system. Finally when electro-active ligand involving the tetrathiafulvalene fragment is used, the modulation of the physical properties depending of its oxidation state can be ambitioned.

Multiple Properties Single-Molecule Magnets

Isotopic Enrichment of Single-Molecule Magnets

Keywords: Single-Molecule Magnet, Isotopes, Molecular Magnetism

Single-Molecule Magnets (SMMs) are molecular objects capable of storing magnetic information at low temperatures. However, the opening of the hysteresis cycle is thwarted by quantum phenomena (tunnel effect), the origin of which is a perturbation of the electronic magnetic moment. Hyperfine coupling is one of these perturbations and we are developing an original strategy, based on isotopic enrichment, which allows to modulate this coupling. We have applied this strategy to Dy(III) complexes functioning as magnet molecules and highlighted significant modifications of the relaxation phenomena at low temperature as a function of the nuclear spin of the Dy(III) ion but also as a function of the hyperfine coupling constant. This work shows that it is possible to explore the performance of magnet molecules thanks to isotopic enrichment and that, in addition, nuclear spin is a tool for manipulating the electronic magnetic moment on the molecular scale for calculation applications. quantum. This incites us to explore other lanthanide in other systems to confirm or infirm our first assumptions.

Isotopic Enrichment of Single-Molecule Magnets

Transition-metal complexes of unsymmetricaly-substituted Schiff base ligands for nonlinear optics

Keywords: transition metals; Schiff bases; donor-acceptor; nonlinear optics.

The Schiff base family constitutes a major class of ligands in inorganic chemistry. Their formidable success relies on their high affinity for a great number of metal ions in various oxidation states to form a wide range of stable complexes, and their modular synthesis, which allows for a convenient tuning of both the electronics of the ligand and the steric hindrance around the metal. They found numerous applications in both chemical and biological processes. In the field of functional molecular materials, complexes of assymmetric Schiff bases that are dipolar molecules bearing electron donor and acceptor groups connected through a π-conjugated spacer, have proven to be efficient chromophores exhibiting large second-order nonlinear optical (NLO) responses controlled by low-energy metal-to-ligand charge transfer (MLCT) excitations. On the other hand, they show excellent catalytic activities in various reactions at high temperatures and in the presence of moisture. Our interest has been centered in the design and construction of novel transition metal complexes supported by N2O2-tetradentate unsymmetrically-substituted Schiff base ligands (CCR 2018, 357,  144; NJC 2020, 40, 9190) exhibiting redox-switchable opto-electronic properties (NJC 2019, 43, 10468). Enhancement of the NLO properties was achieved on progressing from small molecules to main-chain oligomers and side-chain metallopolymers. Those complexes are also efficient and reusable precatalyst for the CuAAC (click) reactions (NJC 2016, 40, 3308) and ROP of rac-lactides (polyhedron 2019, 162, 91). This research work is performed as part of the Chilean-French International Research program “Multifunctional Molecules and Materials” (IRP M3-CNRS No. 1207).

Transition-metal complexes of unsymmetricaly-substituted Schiff base ligands for nonlinear optics

Contact : Jean-René Hamon.