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Accueil > Les équipes > Architectures Moléculaires (A.R.C) > Publications

Publications

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2021



  • G. Basuyaux, A. Amar, C. Troufflard, A. Boucekkine, R. Métivier, M. Raynal, J. Moussa, L. Bouteiller, et H. Amouri, « Cyclometallated Pt(II) Complexes Containing a Functionalized Bis-Urea Alkynyl Ligand: Probing Aggregation Mediated by Hydrogen Bonds versus Pt⋅⋅⋅Pt and π−π Interactions », European Journal of Inorganic Chemistry, vol. 2021, nᵒ 35, p. 3622-3631, sept. 2021.
    Résumé : Abstract Neutral cyclometallated Pt(II) complexes [(C^Nt?Bu^Nt?Bu)Pt?R] (4?5) containing a bis-urea alkynyl (R) ligand have been prepared and fully characterized. The dichotomous nature of 4?5 makes it difficult to anticipate which interactions (hydrogen bonds, π?π stacking and Pt???Pt) will dominate their assembly process. The aggregation properties of 4?5 were thus probed by multifarious analytical (UV/Vis, FT-IR, NMR, MS, CD, emission) and computational (DFT, TD-DFT) techniques. CD analyses of sergeants-and-soldiers type mixtures between 4 and an enantiopure Pt-free monomer (S,S)-3 reveal that no amplification of supramolecular helicity occurs in this system. In fact, complex 4 acts as competitor or chain capper, likely through hydrogen bonding, of the homochiral assemblies formed by (S,S)-3. In DMSO, 1H NMR and DOSY analyses indicate that 4 and 5 form aggregates. Likewise, the aggregation is promoted by the addition of H2O as suggested by red shift of the lowest energy emission band, which might originate from a 3MMLCT excited state. TD-DFT calculations confirm that self-aggregation occurs through Pt???Pt and π?π interactions yielding head-to-tail aggregates in DMSO and DMSO/H2O mixtures. Our study therefore suggests a (condition dependent) competitive rather than a cooperative mode of action of the different types of interactions present in aggregates of 4?5.
    Mots-clés : Aggregation, ARC, Bisurea, Competitor, Luminescence, POLYMERES, Pt⋅⋅⋅Pt interactions, Sergeants-and-soldiers.

2020



  • R. El-Hnayn, L. Canabady-Rochelle, C. Desmarets, L. Balan, H. Rinnert, O. Joubert, G. Medjahdi, H. Ben Ouada, et R. Schneider, « One-Step Synthesis of Diamine-Functionalized Graphene Quantum Dots from Graphene Oxide and Their Chelating and Antioxidant Activities », Nanomaterials, vol. 10, nᵒ 1, p. 104, janv. 2020.
    Résumé : 2,2’-(Ethylenedioxy)bis(ethylamine)-functionalized graphene quantum dots (GQDs) were prepared under mild conditions from graphene oxide (GO) via oxidative fragmentation. The as-prepared GQDs have an average diameter of ca. 4 nm, possess good colloidal stability, and emit strong green-yellow light with a photoluminescence (PL) quantum yield of 22% upon excitation at 375 nm. We also demonstrated that the GQDs exhibit high photostability and the PL intensity is poorly affected while tuning the pH from 1 to 8. Finally, GQDs can be used to chelate Fe(II) and Cu(II) cations, scavenge radicals, and reduce Fe(III) into Fe(II). These chelating and reducing properties that associate to the low cytotoxicity of GQDs show that these nanoparticles are of high interest as antioxidants for health applications.
    Mots-clés : 2, 2’-(ethylenedioxy)bis(ethylamine), ARC, graphene quantum dots, optical properties, POLE 1, redox-active nanoparticles.


  • A. Li, Y. Li, L. - M. Chamoreau, C. Desmarets, L. Lisnard, et Y. Journaux, « A Bis-Polydentate Oxamate-Based Achiral Ligand That Can Stabilize a Macrocyclic Mixed Valence Compound or Induce a 1D Helical Chain », European Journal of Inorganic Chemistry, vol. 2020, nᵒ 34, p. 3311-3319, 2020.
    Résumé : The reaction of the N-(2-hydroxyphenyl)oxamate ligand (ohpma) has been investigated with cobalt(II) and copper(II) ions. It has led to two coordination compounds, (TMA)3[CoIII(ohpma)2CoII(MeOH)23]·10H2O·5MeOH (1) and (HNEt3)[Cu(ohpma)] (2). Both compounds have been characterized by single-crystal X-ray diffraction and magnetometry. The X-ray diffraction studies have revealed atypical structures that are not commonly observed in oxamate coordination chemistry with a macrocyclic arrangement for the mixed-valence cobalt-based complex 1, and a helical chiral chain for compound 2. In the latter, the bis-polydentate nature of the (ohpma)3– ligand with distinct tridentate and bidentate coordination sites creates a chirogenic center on the copper ion. The investigation of the magnetic properties shows for complex 1 a single-molecule magnet behavior detectable under static field, while antiferromagnetic interactions dominate the behavior of 2.
    Mots-clés : ARC, ERMMES, POLE 1, POLE 2.

2018



  • S. ben Moussa, A. Mehri, M. Gruselle, P. Beaunier, G. Costentin, et B. Badraoui, « Combined effect of magnesium and amino glutamic acid on the structure of hydroxyapatite prepared by hydrothermal method », Materials Chemistry and Physics, vol. 212, p. 21-29, juin 2018.
    Résumé : Magnesium modified calcium hydroxyapatite of different Mg/Ca compositions have been synthesized using the hydrothermal method in the presence of glutamic acid. The resulting materials have been characterized by X-ray powder diffraction, chemical analysis, IR Spectroscopy and Transmission Electron Microscopy (TEM). X-ray diffraction analysis shows that the resulting materials consist of a single phase having an apatitic structure. IR spectroscopy highlights the presence of carboxylic groups for the organic moieties grafted onto the apatitic surface. The surface properties of apatite samples are determined.
    Mots-clés : Apatite surface, ARC, Glutamic acid, Hybrid compound, Hydrothermal method, POLE 1.
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