Carine Duhayon

Tuberculosis remains a major global health challenge, motivating the development of innovative drug delivery strategies. Herein, polyphosphorhydrazone dendrimers were investigated as covalent nanocarriers for anti-tuberculosis drugs. Three dendrimer families, including two novel glycoluril-based architectures, were synthesized and functionalized with several anti-tuberculosis drugs or fragments thereof (isoniazid, pyrazinamide, and thioacetazone), via cleavable acylhydrazone or ester linkages. Isoniazid-functionalized dendrimers bearing acylhydrazone linkages displayed the highest activity against Mycobacterium tuberculosis, with a minimum inhibitory concentration as low as 0.097 μM per dendrimer for the glycoluril-cored generation-zero dendrimer, corresponding to 0.39 μM per isoniazid fragment, an approximately two-fold improvement over free isoniazid. In contrast, ester-functionalized dendrimers were inactive. The most potent dendrimers retained activity against rifampicin-, ethambutol-, and streptomycin-resistant strains, but were inactive against isoniazid-resistant strains and non-tuberculous mycobacteria. Cytotoxicity studies revealed a favorable selectivity index exceeding 100. These results identify low-generation glycoluril-cored polyphosphorhydrazone dendrimers as promising platforms for anti-tuberculosis drug delivery.

The ability to tune the redox and photophysical properties of transition metal complexes is crucial for expanding their functional scope across diverse applications. Such modulation is commonly achieved through rational ligand design and the deliberate assembly of heteroleptic complexes featuring tailored coordination environments. However, the selective synthesis of tris-heteroleptic metal complexes featuring three different bidentate ligands remains a major challenge in coordination chemistry. These specific architectures are still rarely reported in the literature, largely due to their synthetic complexity and the lack of general, reliable protocols for their preparation. In this general context, we present an efficient synthetic strategy for the preparation of octahedral tris-heteroleptic Ru(II) phosphonium ylide complexes incorporating three distinct chelating ligands. The isolated pyridyl-phosphonium ylide Ru(II) complexes exhibit intense and tunable photoluminescence, with emission profiles spanning a broad spectral window from sky blue to near-infrared, along with a wide range of redox potentials. The successful isolation of these well-defined Ru species highlights the crucial influence of ligand electronic and steric properties on the excited-state behavior of the metal center.

Hydrostatic pressure can be a valuable aid in the structural study of a chiral compound, avoiding disorder and providing an unambiguous description of the stereochemistry of the chemical system. This follows from the single-crystal X-ray diffraction studies performed on the chiral framework [Y4(ox)5(L*)2(H2O)4]·2.5H2O, 1 (L* = (S,S)-1,3-bis(carboxyethyl)imidazolium)), for hydrostatic pressures up to 3.6 GPa. The positional disorder for the chiral groups obtained at ambient pressure vanished when the crystal was subjected to hydrostatic pressure (2.4 GPa), unambiguously confirming the stereoisomer for all the chiral carbon centers and the homochiral nature of 1.

The electrochemical and photophysical properties of two series of ruthenium bis(bipyridine) complexes featuring either a pyridine-phosphonium ylide (PC) or a pyridine-iminophosphorane (PN) ligand were synthesized. Three different bipyridines were employed allowing the synthesis of six P-ylide Ru^II complexes. All the complexes were fully characterized by multinuclear NMR spectroscopy, HR-mass spectrometry, as well as X-ray crystallography, and no major difference was observed between them. In cyclic voltammetry, the measured potentials agree with the electronic properties of the bipyridine ligands and underline the strong electron donation of the phosphonium ylide. Indeed, the oxidation is facilitated and the reductions become more difficult compared to the corresponding [Ru(^Rbpy)₃] complexes. The absorption spectra of the PC and PN Ru^II complexes are similar, with a bathochromic shift compared to polypyridine Ru^II complexes, which is amplified in the presence of electron-withdrawing substituents on the bipyridine. Regarding luminescence, the PC complexes emit at a lower energy than the PN analogues. In addition, the associated lifetime depends on both the nature of the P-ylide and the substituents on the bipyridine ligand. This was related to the different adiabatic ³MC/³MLCT gap calculated at the DFT level, which is larger for two iminophosphorane complexes exhibiting a lifetime of the order of a few hundred nanoseconds.

Solvothermal conditions enable the formation of polynuclear Co(II) compounds with 4′‐[p‐(Imidazol‐1‐yl)phenyl]‐2,2′:6′,2′′‐terpyridine (L) acting as a bridging ligand. 1D coordination polymer [Co₂(L)₂(Cl)₄].5H₂O, 1, and discrete [Co₂(L)(Cl)₄(DMF)]₂, 2, can be selectively obtained by tuning the CoCl₂/L ratio involved in the reaction. A peculiar feature in complex 2 is the occurrence of tetrahedral and octahedral Co centers bridged by a chloride atom, whereas Co(II) is six‐coordinated in 1. The crystal structures of both compounds have been characterized by single‐crystal X‐ray diffraction studies. Magnetic studies have evidenced a canted antiferromagnetic (i.e., weak ferromagnet) behavior for 2.

Air-stable photoluminescent cyclometallated phosphonium ylide-based iridium(iii) complexes are highly active catalysts in visible-light single electron (SET) and energy transfer (EnT) processes.

The integration of organic species with polyoxometalates leads to the formation of hybrid materials that benefit from the combined functionalities of both components. These organo-inorganic systems are of great interest due to their potential synergistic behavior. Developing straightforward and efficient synthetic approaches to design such materials combining the rigidity of the inorganic backbone and the tunability of organic units remains a key objective in the field of materials chemistry. In this work, we present a simple "one-pot" synthesis route for the compound (C₆H₂₀N₃)₂[P₂Mo₅O₂₃].1.5H₂O. Structural characterization was performed using single-crystal X-ray diffraction alongside infrared and UV-Visible spectroscopy. The compound crystallizes in the monoclinic system, space group P2₁/c, with the following unit cell parameters: a = 18.9626(2) Å, b = 10.8514(1) Å, c = 16.4933(1) Å, β = 107.37(1)°, and Z = 4. Its structure is based on a diphosphomolybdate anion [P₂Mo₅O₂₃]^6-, neutralized by two organic cations (C₆H₂₀N₃)³⁺, and accompanied by 1.5 lattice water molecules. The three-dimensional arrangement is characterized by layered assemblies oriented along the a-axis, stabilized through extensive hydrogen bonding. These layers alternate between polyanionic clusters, organic moieties, and water molecules, forming a robust supramolecular network. Notably, this material displays photochromic behavior, suggesting its potential for applications in responsive optical systems.

Chiral 1D coordination compounds formed by association of either of the enantiomers of [ML(MeOH)Cl]Cl (with M=Mn^II or Fe^II; L stands for either R or S enantiomer of a pentadentate macrocycle) and NBu₄[Fe^III(bpb)(CN)₂], namely: 1D‐[{Fe^III(bpb)(CN)₂}{M^II(L^R)}](PF₆) and 1D‐[{Fe^III(bpb)(CN)₂}{M^II(L^S)}](PF₆) with M=Mn (2R, 2S) and Fe (3R, 3S). The bis(triphenylphosphine)iminium salt of the metallo‐ligand, PNP[Fe^III(bpb)(CN)₂]⋅2H₂O, 1 b, is also described. Their preparations, crystal structures, optical and magnetic properties are reported. Mössbauer spectroscopy confirmed the oxidation state in the [Fe^II−Fe^III] chain, for which AC susceptibility suggests SCM behavior, but for very low T.