Research Themes


A simplified reading of the group's expertise through our various potentially interesting compounds can be illustrated as shown in this diagram.

Since 2017, our research activity is mainly focused on a federating theme for which a high added value is expected (in red on the diagram). Of course, some collaborations/projects on related topics (fluorescent and/or bimodal probes, vectorized radiopharmaceuticals, enzyme inhibitors, multifunctional phenolic platforms...) in collaboration with local, national or international partners are also developed.

General scheme
General scheme

Rhenium(I) complexes: Towards novel luminescent and photoactive systems

So far, tricarbonyl-rhenium complexes have been studied in the team, in the field of radiopharmaceuticals as non-radioactive models of technetium-99m analogue radiocomplexes (diagnostic probes) or nuclear probes for therapeutic purposes (with the radioactive isotope rhenium-188). However, the interest of these complexes goes far beyond that. The complexes are stable, often biocompatible and easily incorporated by living cells.  They are intrinsically phosphorescent and their spectroscopic properties are largely modulated with the chemical structure, hence their interest as luminescent probes for optical imaging. Under light excitation, some of them can also deliver carbon monoxide molecules in a controlled manner (PhotoCORMs complexes for Photochemical CO-Releasing Molecules), knowing that CO is a gas recently identified as efficient in the treatment of cardiovascular diseases and to reduce transplant rejection.

MagenTa team focuses on the elucidation of the structural parameters governing the spectroscopic and photochemical properties of complexes based on the model below, through an in-depth experimental and theoretical study. The aim is to provide original and efficient diagnostic or therapeutic probes.

SCheme 2 english
SCheme 2 english

phosphorescent and/or photoactive tricarbonyl-rhenium(I) complexes

Relevant Results

  • Benzoxazole-pyta(Re(CO)3X) systems

We have recently identified different benzoxazole-[pyta(Re(CO)3X)] (rhenium(I) complexes pyta = pyridine-triazole chelator). Some of which are highly interesting from a spectroscopic point of view. They show (i) a high yellow emission in the solid state with a photoluminescence efficiency of 55% (highest efficiency observed to date for rhenium(I) complexes), (ii) an emission intensity that increases under the aggregation effect  and in the solid state (SLE effect or Solid-state Luminescence Enhancement).

SLE English
SLE English

In this way, we have proved that:

- the isomerism of the pyridine-triazole (pyta) ligand influences the photophysical properties of complexes. Thus, rhenium(I) complexes from a pyridine-1,2,4-triazole chelator exhibit an SLE effect and strong solid-state phosphorescence in contrast to their counterparts from a pyridine-1,2,3-triazole chelator,

- the steric hindrance and/or isomerism of the benzoxaxole moiety allows to optimize the solid-state phosphorescence properties of compounds,

- Some complexes exhibit mechanosensitive luminescence properties (such properties for rhenium(I) complexes have been demonstrated for the first time).

- By (replacing the chloride anchor ligand by a phosphine), photoreactive compounds (PhotoCORMs) were prepared. This photoreactivity is supported by a change in the phosphorescence properties (of interest for theranostics).

Ongoing development: Incorporation of [benzoxazole-pyta(Re(CO)3(PPh3)] complexes in synthetic talc for the development of photoactive mineral gel with antimicrobial application (collaboration with C. Leroux, GT, Toulouse)

Scheme 4 EN
Scheme 4 EN

  • Phenyl-pyta(Re(CO)3X) systems

New systems (replacement of benzoxazole by a substituted aromatic derivative) with similar photo-physical properties  are currently under investigation to get new luminescent materials and bioconjugates for SLE-based bio-imaging applications.

For more details on this topic,  refer to the publications tab and in particular: Dalton 2018 (J. Wang et al.); Dalton 2019 (J. Wang et al.), Chem. Eur. J. 2021 (J.P. Calupitan et al.), Dalton 2021 (A.D. Hernandez Mejias et al.), Dalton 2021 (A. Poirot et al.).

Other researches

  • Rhenium(I) complexes as inhibitors of Carbonic Anhydrases IX and XI

In a study combining calculations, docking and experimentation, original tricarbonyl-rhenium(I) complexes carrying a sulphonamide or coumarin arm were developed. They exhibited nanomolar inhibitory activity against Carbonic Anhydrases IX (hCA IX) and XII (hCA XII), as well as very high selectivity against hCA IX and hCA XII with respect to the off-target isoforms hCA I and hCA II.

For more details on this topic, refer to the publications tab and in particular: J. Enzyme Inhib. Med. Chem. 2019 (Y. Aimene et al.); Crystals 2021 (Y. Aimene et al.).
 

  • Imaging (nano)probes
Development of a bimodal nano-probe for medical imaging, combining the spatial precision of MRI with the high sensitivity of nuclear imaging in collaboration with the LCC and ToNIC laboratories (Toulouse).  Our expertise in the synthesis of bifunctional chelating ligands towards technetium-99m, PET elements such as copper-64 and gallium-68 or gadolinium is required.


Radiolabelled GBVA10-9 or CPB peptides for diagnosis and/or therapy of hepatocellular carcinoma.

The reseaches are developed in collaboration with ENSC Rennes (FRM project) where our expertise in the synthesis of bifunctional chelating ligands towards technetium-99m (or even rhenium-188) is required.

For more details on this topic,  refer to the publications tab and in particular: New J. Chem. 2020 (P. Mathieu et al.).

Our partnerships

  • Dr. M. Wolff, Vienna University (Calculations, modelisation and crystallography)
  • Dr. A. Erriguible,  Bordeaux University (Nanoparticules)
  • Dr. C. Amiens, LCC Toulouse (Nanoparticules)
  • Dr. B. Delavaux-Nicot, LCC Toulouse (Electrochemistry)
  • Dr. C. Le Roux, GET Toulouse (synthetic talc Hybrides )
  • Dr. R. Métivier, Dr C. Allain, ENS Paris Saclay  (Photophysics)
  • Dr. S. Cammas-Marion, ENSCR (Polymers, nanoparticules)
  • Dr. N. Lepareur, anticancer Center Eugène Marquis, Rennes (Radiomarquage Tc-99m, Re-188)
  • Drs. F. Desmoulin, I. Quelven-Bertin, Pr. P. Payoux, ToNIC Toulouse (Radiomarquage, IMR, in vivo test)
  • Dr. A. Seridi, Guelma University, Algéria (Calculations, docking)
  • Dr. J.-Y. Winum, Institute of Biomolecules Max Mousseron, Montpellier (Enzymology)
  • Pr. Dr. A Ngezahayo, Institute of Cell Biology and Biophysics, Hannover (cell physiology)