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Accueil > Les équipes > Equipe de Recherche en Matériaux Moléculaires et Spectroscopies (ERMMES) > Publications

Publications

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2019



  • J. Besnardiere, B. Ma, A. Torres-Pardo, G. Wallez, H. Kabbour, J. M. González-Calbet, H. J. Von Bardeleben, B. Fleury, V. Buissette, C. Sanchez, T. Le Mercier, S. Cassaignon, et D. Portehault, « Structure and electrochromism of two-dimensional octahedral molecular sieve h’-WO3 », Nature Communications, vol. 10, nᵒ 1, p. 327, janv. 2019.
    Résumé : Octahedral molecular sieves (OMS) are built of transition metal-oxygen octahedra that delimit sub-nanoscale cavities. Compared to other microporous solids, OMS exhibit larger versatility in properties, provided by various redox states and magnetic behaviors of transition metals. Hence, OMS offer opportunities in electrochemical energy harnessing devices, including batteries, electrochemical capacitors and electrochromic systems, provided two conditions are met: fast exchange of ions in the micropores and stability upon exchange. Here we unveil a novel OMS hexagonal polymorph of tungsten oxide called h’-WO3, built of (WO6)6 tunnel cavities. h’-WO3 is prepared by a one-step soft chemistry aqueous route leading to the hydrogen bronze h’-H0.07WO3. Gentle heating results in h’-WO3 with framework retention. The material exhibits an unusual combination of 1-dimensional crystal structure and 2-dimensional nanostructure that enhances and fastens proton (de)insertion for stable electrochromic devices. This discovery paves the way to a new family of mixed valence functional materials with tunable behaviors.
    Mots-clés : ERMMES, POLE 2.


  • N. Daffé, J. - R. Jiménez, M. Studniarek, A. Benchohra, M. - A. Arrio, R. Lescouëzec, et J. Dreiser, « Direct Observation of Charge Transfer and Magnetism in Fe4Co4 Cyanide-Bridged Molecular Cubes », The Journal of Physical Chemistry Letters, vol. 10, nᵒ 8, p. 1799-1804, avr. 2019.
    Résumé : We have studied the zero-dimensional cubane molecular correspondent of a Prussian blue analogue Cs–Fe4Co4 at low temperature and high magnetic field by means of L-edge X-ray absorption spectroscopy and X-ray magnetic circular dichroism. We probe the magnetic and electronic structures of Fe and Co separately upon light irradiation, which allows us to observe directly the electron transfer coupled to a spin transition phenomenon within the molecular cubes and to investigate the nature of the metastable photoexcited state. The magnetic moments in the photoexcited state are found to be M = 1.3μB (Mspin = 0.59μB with large orbital moment, Morbit = 0.74μB) for low-spin FeIII and M = 1.5μB (Mspin = 1.08μB with orbital moment, Morbit = 0.41μB) for high-spin CoII at 2 K and 6.8 T. From our results, we evidence that a strong antiferromagnetic coupling between the metal ions can be ruled out.
    Mots-clés : ERMMES, POLE 2.


  • S. De, A. Flambard, D. Garnier, P. Herson, F. H. Köhler, A. Mondal, K. Costuas, B. Gillon, R. Lescouëzec, B. Le Guennic, et F. Gendron, « Probing the Local Magnetic Structure of the [FeIII(Tp)(CN)3]− Building Block Via Solid-State NMR Spectroscopy, Polarized Neutron Diffraction, and First-Principle Calculations », Chemistry – A European Journal, vol. 25, nᵒ 52, p. 12120-12136, 2019.
    Résumé : Abstract The local magnetic structure in the [FeIII(Tp)(CN)3]− building block was investigated by combining paramagnetic Nuclear Magnetic Resonance (pNMR) spectroscopy and polarized neutron diffraction (PND) with first-principle calculations. The use of the pNMR and PND experimental techniques revealed the extension of spin-density from the metal to the ligands, as well as the different spin mechanisms that take place in the cyanido ligands: Spin-polarization on the carbon atoms and spin-delocalization on the nitrogen atoms. The results of our combined density functional theory (DFT) and multireference calculations were found in good agreement with the PND results and the experimental NMR chemical shifts. Moreover, the ab-initio calculations allowed us to connect the experimental spin-density map characterized by PND and the suggested distribution of the spin-density on the ligands observed by NMR spectroscopy. Interestingly, significant differences were observed between the pseudo-contact contributions of the chemical shifts obtained by theoretical calculations and the values derived from NMR spectroscopy using a simple point-dipole model. These discrepancies underline the limitation of the point-dipole model and the need for more elaborate approaches to break down the experimental pNMR chemical shifts into contact and pseudo-contact contributions.
    Mots-clés : ERMMES, POLE 2.


  • D. Garnier, A. Mondal, Y. Li, P. Herson, L. - M. Chamoreau, L. Toupet, M. Buron Le Cointe, E. M. B. Moos, F. Breher, et R. Lescouëzec, « Tetranuclear [FeII2FeIII2]2+ molecular switches: [FeII(bik)2(N–)2] spin-crossover complexes containing [FeIII(Tp)(CN)3]– metalloligands as N-donor », Comptes Rendus Chimie, mai 2019.
    Résumé : Three novel mixed valence cyanide-bridged {FeIII2FeII2} square complexes were obtained through the self-assembling of [FeIII(Tp)(CN)3]- or [FeIII(Tp*)(CN)3]− cyanido building blocks with the in situ formed [FeII(bik)2(S)2] complex (Tp = hydrotris (pyrazol-1-yl)borate, Tp* = hydrotris (3,5-dimethyl-pyrazol-1-yl)borate, bik = bis(1-methylimidazol-2-yl)ketone, S = solvent). The structures of these three complexes (2, 3 and 4) are reminiscent of that of our previously published square complex {[FeIII(Tp)(CN)3]2 [FeII(bik)2]2}·[FeIII(Tp)(CN)3]2·18H2O·4CH3OH (1). They consist of cyanide-bridged square dicationic complexes, ClO4− (2 and 3) or BF4− (4) counterions and solvate molecules. The FT-IR cyanide stretching vibrations observed at νCN ≈ 2145–60 cm−1 are typical of {FeIII–CN–FeII} moieties. The investigation of the magnetic properties of 2 reveals the occurrence of spin-crossover centered at T1/2 = 227 K. The χMT variation, ca. 7 cm3 mol−1 K, reflects the complete spin-state change occurring on both {FeII(bik)(–NC)2} moieties (–NC represents the cyanido building blocks). The Slichter–Drickamer model leads to a weak cooperativity factor, Γ = 1.6 kJ mol−1 (with Γ < 2RT1/2), which reflects the gradual spin-state change. This is in agreement with the molecular structure of 2, which does not present significant intermolecular interactions. The calculated enthalpy and entropy variations associated with the spin-state equilibrium are ΔH = 24 kJ mol−1 and ΔS = 105 J K−1 mol−1. In contrast, 3 and 4 show only partial spin-crossover in the accessible temperature range (2–400 K) as the T1/2 are shifted toward higher temperatures (ca. T1/2 > 400 K). Although no photomagnetic effect is observed for 3, compound 4 shows a moderate increase in the magnetization upon irradiation at low temperature. This phenomenon is ascribed to the light-induced excited spin-state trapping (LIESST) effect. Interestingly, the complex 2 also shows a remarkable LIESST effect, which is observed with different laser lights covering the visible and near-infrared range. The resulting χMT value obtained in the photoinduced state suggests the occurrence of a ferromagnetic interaction inside the {FeIII–CN–FeII} units. Résumé Trois nouveaux complexes carrés {FeIII2FeII2} à pont cyanure et à valence mixte ont été obtenus par auto-assemblage des précurseurs cyanurés [FeIII(Tp)(CN)3]− ou [FeIII(Tp*)(CN)3]− et du complexe cationique [FeII(bik)2(S)2] formé in situ (Tp = hydrotris (pyrazol-1-yl)borate, Tp* = hydrotris (3,5-dimethyl-pyrazol-1-yl)borate, bik = bis(1-methylimidazol-2-yl)cétone, S = solvant). Les structures de ces trois complexes (2, 3 et 4) sont similaires à celle du complexe {[FeIII(Tp)(CN)3]2[FeII(bik)2]2}[FeIII(Tp)(CN)3]2·18H2O·4CH3OH (1) préalablement publié. Elles sont constituées de complexes carrés dicationiques à pont cyanure, de contre-ions ClO4− (2 and 3) ou BF4− (4) et de molécules de solvant. Les vibrations d’élongation des cyanures, observée en spectroscopie IR à νCN ≈ 2145–60 cm−1, sont caractéristiques d'unités {FeIII–CN–FeII}. L’étude des propriétés magnétiques de 2 révèle un équilibre de spin centré à T1/2 = 227 K. La variation du produit χMT, ca. 7 cm3 mol−1 K, traduit une conversion de spin complète sur chacune des unités {FeII(bik)(–NC)2} du carré (–NC représente le complexe précurseur cyanuré). L'analyse des données par le modèle de Slichter–Drickamer conduit à un faible facteur de coopérativité, Γ = 1.6 kJ mol−1 K (with Γ < 2RT1/2), en accord avec un changement d’état de spin graduel. Ces données sont en accord avec la structure de 2 qui ne montre pas d'interactions intermoléculaires notables. Les valeurs des variations d'enthalpie et d'entropie associées à la conversion de spin sont ΔH = 24 kJ mol−1 et ΔS = 105 J K−1 mol−1. Au contraire de 2, les composés 3 and 4 présentent seulement une conversion de spin partielle dans le domaine de température exploré (2–400 K), avec des valeurs T1/2 déplacées vers les hautes températures (ca. T1/2 > 400 K). Tandis qu'on n'observe pas d'effet photomagnétique pour 3 et seulement un faible effet dans 4, le composé 2 présente une forte augmentation de son aimantation sous irradiation à basse température. Cet effet est dû au piégeage photo-induit d'un état excité de spin (effet « LIESST », Light-Induced Excited Spin-State Trapping). Il est observé avec différentes sources laser couvrant le spectre visible et le proche infrarouge. Les valeurs de χMT obtenues dans l’état photo-induit suggèrent la présence d'une interaction ferromagnétique au sein de la paire {FeIII–CN–FeII}.
    Mots-clés : ERMMES, POLE 2.


  • A. Harbi, H. Moutaabbid, Y. Li, C. Renero-Lecuna, M. Fialin, Y. Le Godec, S. Benmokhtar, et M. Moutaabbid, « The effect of cation disorder on magnetic properties of new double perovskites La2NixCo1-xMnO6 (x = 0.2–0.8) », Journal of Alloys and Compounds, vol. 778, p. 105-114, mars 2019.
    Résumé : Solid solutions of new double perovskite oxides La2NixCo1-xMnO6 (x = 0.2, 0.25, 0.5, 0.75, 0.8) were synthesized by solid-state reaction method. The X-ray powder diffraction data show that all the compounds crystallize in the monoclinic structure with space group P21/n at room temperature. The elementary composition of the powders was determined by the electron Probe Microanalysis. Raman and IR spectra show strong bands at (520, 650 cm−1) and (426, 600 cm−1) respectively, attributed to the stretching vibration of Ni/Co-O and Mn-O bonds in the structure. The magnetic studies for all the compounds have been performed in both DC and AC magnetic fields in the temperature range from 2 to 300 K. All samples exhibit a main paramagnetic to ferromagnetic (PM-FM) transition between 232 K and 260 K, and their Curie temperature increases rapidly with increasing x values. Three samples with x = 0.2, 0.25 and 0.5 respectively display also a secondary PM-FM transition between 200 K and 208 K. The thermal variation of out of phase component of AC susceptibility presents also frequency-dependent transitions between 65 K and 110 K unfolding the existence of super-paramagnetic mono-domains in all samples. The band gap energy has been calculated and revealing semiconductor behavior for all samples.
    Mots-clés : ERMMES, POLE 2.


  • M. Okubo, J. Long, D. R. Talham, et R. Lescouëzec, « Solid-state electrochemistry of metal cyanides », Comptes Rendus Chimie, vol. 22, nᵒ 6, p. 483 - 489, 2019.
    Résumé : Efficient energy storage in the form of batteries contributes to building sustainable society. As advanced batteries need positive electrode materials capable of larger capacity, higher voltage, and lower cost, it is important to search for novel electrode materials. Among various inorganic/organic materials, cyanido-bridged coordination compounds are promising candidates for battery electrodes due to their ability to undergo solid-state redox reaction associated with ion (de)intercalation. In this review, recent results about the thermodynamic and kinetic aspects of the solid-state electrochemistry of cyanido-bridged coordination compounds are summarized, providing a fundamental basis toward developing cyanide electrodes for advanced batteries. Résumé Le stockage de l’énergie dans des batteries performantes est un élément clé pour le développement des énergies renouvelables et d'un modèle de société durable. Un des défis pour construire de nouvelles batteries plus performantes est le développement de matériaux d'intercalation pour cathode présentant de plus grandes capacités, de plus grands voltages et des coûts réduits. Parmi les divers matériaux organiques et inorganiques explorés, les polymères de coordination à pont cyanure sont des candidats prometteurs. Ceux ci peuvent s'oxyder et se réduire à l’état solide en (dés)intercalant des ions. Dans cette revue, quelques résultats récents sur les aspects thermodynamiques et cinétiques des propriétés électrochimiques des polymères de coordination à pont cyanure sont résumés, démontrant leur potentiel intérêt comme életcrodes dans de nouvelles batteries.
    Mots-clés : ERMMES, POLE 2.
    Note Note
    <p>Forty years of exchange interactions on the occasion of the 75th birthday of Michel Verdaguer</p>

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  • W. X. C. Oliveira, W. D. do Pim, C. B. Pinheiro, Y. Journaux, M. Julve, et C. L. M. Pereira, « Monitoring the hydrogen bond net configuration and the dimensionality of aniline and phenyloxamate by adding 1H-pyrazole and isoxazole as substituents for molecular self-recognition », CrystEngComm, vol. 21, nᵒ 17, p. 2818-2833, avr. 2019.
    Résumé : This work describes the synthesis and characterization of a new class of oxamic acid derivatives containing pyrazole and isoxazole as substituents to investigate their ability to form hydrogen bonds aiming at applying them in crystal engineering and molecular self-recognition. In this respect, we report a new synthesis of 2-(4-nitrophenyl)-1,3-propanedial (1) in high yield using SOCl2 as a chlorinating agent. The new oxamic esters 4-(1H-pyrazol-4-yl)phenylene-N-(ethyloxamate) (2d) and 4-(1,2-oxazol-4-yl)phenylene-N-(ethyloxamate) (3d) were prepared from 1. The synthetic route consists of the cyclisation of 1 either with hydrazine to afford 4-(-aminophenyl)-1H-pyrazole (2a) or with hydroxylamine to obtain the isoxazole-based molecule 4-(4-nitrophenyl)-1,2-oxazole (3a). The reduction of 2a and 3a was carried out in an acidic/tin solution to yield 4-(4-ammoniophenyl)-1H-pyrazol-2-ium trichlorostannate(II) chloride monohydrate (2b) and 4-(4-ammoniophenyl)-1,2-oxazole hexachlorostannate(IV) (3b). Basic extraction of 3b provided 4-(4-aminophenyl)-1,2-oxazole (3c). The reduction of 2a to 4-(4-aminophenyl)-1H-pyrazole (2c) was achieved by means of hydrazine associated with supported palladium on carbon. The condensation of 2c and 3c with ethyl chlorooxoacetate delivers oxamic esters 2d and 3d. In n-tetrabutylammonium hydroxide solution 2d is fully hydrolyzed, obtaining the n-tetrabutylammonium salt of 4-(1H-pyrazole-4-yl)phenylene-N-oxamate as a hemihydrate (2e). The low stability of isoxazole molecules in basic solutions was proved by crystallizing the n-tetrabutylammonium salt of 1-cyano-1-(4-nitrophenyl)-2-oxoethanide (3f) (obtained by cleavage of 3d with n-Bu4NOH) and preparing its conjugated acid 2-(4-nitrophenyl-3-oxopropanenitrile (3e). The structures of 2b, 3b, 3d and 2e were solved by single crystal X-ray diffraction techniques. The analysis of their crystal packing reveals hydrogen bond features compatible for all compounds as well as some differences depending on the pH of the crystallization solution and the presence or absence of the oxamate group due to the increase of hydrogen bond donors and acceptors.
    Mots-clés : ERMMES, POLE 2.
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  • O. Stetsiuk, V. Synytsia, S. R. Petrusenko, V. N. Kokozay, A. El-Ghayoury, J. Cano, F. Lloret, M. Julve, B. Fleury, et N. Avarvari, « Co-existence of ferro- and antiferromagnetic interactions in a hexanuclear mixed-valence CoIII2MnII2MnIV2 cluster sustained by a multidentate Schiff base ligand », Dalton Transactions, vol. 48, nᵒ 31, p. 11862-11871, 2019.
    Résumé : The successful utilization of the “direct synthesis” approach yielded the unprecedented hexanuclear complex of formula [Co2MnII2MnIV2(L1)4Cl2(μ3-O)2(dmf)4]·2dmf (1) (H3L is the Schiff base derived from the condensation of salicylaldehyde and 3-aminopropane-1,2-diol). Single crystal X-ray analysis revealed that 1 crystallizes in the monoclinic system P21/c and it contains a rare mixed-valence CoIII2MnII2MnIV2(μ2-O)8(μ3-O)2 core where all metal ions are linked through the phenolato and alkoxo groups of the L3− ligand. Besides the charge balance resulting from the X-ray structure, the oxidation state of the metal ions has been confirmed by XPS spectroscopy. Cryomagnetic studies indicate the coexistence of ferro- (MnIV–MnII, J2 = +1.10(3) cm−1, J3 = +2.19(3) cm−1; MnII–MnII, j = +0.283(3) cm−1) and antiferromagnetic interactions (MnIV–MnIV, J1 = −17.31(4) cm−1), with the six-coordinate CoIII ions being diamagnetic. DFT type calculations were carried out to substantiate these values. The energy diagram for the different spin states using the best-fit parameters shows the occurrence of six low-lying spin states (S = 0–5) which are close in energy but clearly separated from the remaining ones, with the ground spin state being S = 5. Complex 1 is found to be the first example where weak ferromagnetic exchange between MnII ions through the long –O–MnIV–O– pathway takes place.
    Mots-clés : ERMMES, POLE 2.

2018



  • T. F. C. Cruz, C. A. Figueira, J. C. Waerenborgh, L. C. J. Pereira, Y. Li, R. Lescouëzec, et P. T. Gomes, « Synthesis, characterization and magnetism of homoleptic bis(5-aryl-2-iminopyrrolyl) complexes of iron(II) and cobalt(II) », Polyhedron, vol. 152, p. 179-187, 2018.


  • S. De, L. - M. Chamoreau, H. El Said, Y. Li, A. Flambard, M. - L. Boillot, S. Tewary, G. Rajaraman, et R. Lescouëzec, « Thermally-Induced Spin Crossover and LIESST Effect in the Neutral [FeII(Mebik)2(NCX)2] Complexes: Variable-Temperature Structural, Magnetic, and Optical Studies (X = S, Se; Mebik = bis(1-methylimidazol-2-yl)ketone) », Frontiers in Chemistry, vol. 6, août 2018.


  • S. De, S. Tewary, D. Garnier, Y. Li, G. Gontard, L. Lisnard, A. Flambard, F. Breher, M. - L. Boillot, G. Rajaraman, et R. Lescouëzec, « Solution and Solid-State Study of the Spin-Crossover [FeII(R-bik)3](BF4)2 Complexes (R = Me, Et, Vinyl) », European Journal of Inorganic Chemistry, vol. 2018, nᵒ 3-4, p. 414-428, janv. 2018.
    Résumé : The magnetic properties of three spin-crossover complexes, [FeII(R-bik)3](BF4)2·nH2O (1–3), based on bis(imidazolyl)ketone ligands, were investigated in solution and the solid state. Their properties were compared with those of the ketone-free analogue, [FeII(bim)3](OTf)2 (4). The alkyl and vinyl R groups have weak influence on the transition temperature, T1/2, in solution, while stronger differences are observed in the solid state, because different intermolecular interactions occur in 1–3. The spin-state equilibria in solution were followed by SQUID magnetometry and the Evans NMR spectroscopy method. Interestingly, the equilibria can also be simply and efficiently probed by following the temperature dependence of an adequately chosen 1H chemical shift. Overall, these experiments give coherent results, with T1/2 located between 320 and 335 K, a narrow range, in comparison with the solid state. DFT calculations have allowed the rationalization of the magnetic differences. The molecular-orbital and spin-density calculations reveal that the presence of the C=O group between the imidazolyl units in the ligands of 1–3 leads to an extended aromatic system, an effective π-acceptor effect, stabilizing the LS state and reducing the LS–HS gap, in comparison with 4.
    Mots-clés : Density functional calculations, ERMMES, Iron, Paramagnetic NMR spectroscopy, POLE 2, Spin crossover.
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  • J. - R. Jiménez, A. Sugahara, M. Okubo, A. Yamada, L. - M. Chamoreau, L. Lisnard, et R. Lescouëzec, « A [FeIII(Tp)(CN)3]− scorpionate-based complex as a building block for designing ion storage hosts (Tp: hydrotrispyrazolylborate) », Chemical Communications, avr. 2018.
    Résumé : Using a scorpionate-based complex, [FeIII(Tp)(CN)3]−, as a building block, a new cyanide-based molecular material [{FeIII(Tp)(CN)3}2NiII(H2O)2]·4H2O (1), which can be viewed as a lower dimensional model of Prussian blue analogues, was investigated as a lithium-ion storage host.
    Mots-clés : ERMMES, POLE 2.
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  • Y. Journaux, J. Ferrando-Soria, E. Pardo, R. Ruiz-Garcia, M. Julve, F. Lloret, J. Cano, Y. Li, L. Lisnard, P. Yu, H. Stumpf, et C. L. M. Pereira, « Design of Magnetic Coordination Polymers Built from Polyoxalamide Ligands: A Thirty Year Story », European Journal of Inorganic Chemistry, vol. 2018, nᵒ 3-4, p. 228–247, janv. 2018.
    Résumé : The aim of this review is to pay tribute to the legacy of O. Kahn. Kahn's credo was to synthesize magnetic compounds with predictable structure and magnetic properties. This is illustrated herein with results obtained by Kahn's group during his Orsay period thirty years ago, but also on the basis of our recent results on the synthesis of coordination polymers with oxamate ligands. The first part of this review is devoted to a short description of the necessary knowledge in physics and theoretical chemistry that Kahn and his group have used to select oxamate ligands, the complex-as-ligand strategy and the synthesis of heterobimetallic systems. Then, we describe the strategies we have later used to obtain the desired target compounds. The use of complexes as building-blocks, associated to a control of the metal ions chirality and stoichiometry, allowed us to obtain coordination polymers with predictable dimensionality. For the synthesis of single-chain magnets (SCMs) we show that the ligand chemical flexibility makes the isolation of the chains in the solid and the occurence of slow magnetic relaxation possible. For 1D and 2D molecule-based magnets (MBMs), the magnetic ordering strongly depends on the interchain or interplane interactions, which are difficult to control. Again the flexibility of the oxamate ligands allowed their strengthening in the solid sate, yielding MBMs with critical temperatures up to 30 K. We will also present our results on 3D coordination polymers, particularly on the porous magnets displaying large octagonal channels. This family of porous MBMs possess outstanding chemical properties, such as post-synthetic transformation in the solid state. Finally, we will also show that oxamate ligands allows the design of multifunctional materials, as in the case of the first chiral SCM. Overall, the results presented in this review show the impressive potential the oxamate ligands have for the design of coordination polymers.
    Mots-clés : Bridging ligands, Coordination Polymer, ERMMES, Heterometallic complexes, Ligand design, Magnetic properties, Metal-Organic Frameworks, Metallacycles, N, O ligands, POLE 2.
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  • R. Plamont, J. Tami, J. - R. Jimenez, A. Benchohra, O. Khaled, G. Gontard, Y. Li, et R. Lescouëzec, « A soluble cyanide-bridged {Fe <sub>4</sub> Ni <sub>4</sub> } box encapsulating a Cs <sup>+</sup> ion: synthesis, structure and electronic properties », Journal of Coordination Chemistry, vol. 71, nᵒ 5, p. 601-614, mars 2018.


  • T. Zhang, A. Solé-Daura, S. Hostachy, S. Blanchard, C. Paris, Y. Li, J. J. Carbó, J. M. Poblet, A. Proust, et G. Guillemot, « Modeling the Oxygen Vacancy at a Molecular Vanadium(III) Silica-Supported Catalyst », Journal of the American Chemical Society, vol. 140, nᵒ 44, p. 14903-14914, nov. 2018.
    Résumé : Here we report on the use of a silanol-decorated polyoxotungstate, [SbW9O33(tBuSiOH)3]3– (1), as a molecular support to describe the coordination of a vanadium atom at a single-site on silica surfaces. By reacting [V(Mes)3·thf] (Mes = 2,4,6-trimethylphenyl) with 1 in tetrahydrofuran, the vanadium(III) derivative [SbW9O33(tBuSiO)3V(thf)]3– (2) was obtained. Compound 2 displays the paramagnetic behavior expected for a d2-VIII high spin complex (SQUID measurements) with a triplet electronic ground state (ca. 30 kcal·mol–1 more stable than the singlet, from DFT calculations). Compound 2 proves to be a reliable model for reduced isolated-vanadium atom dispersed on silica surfaces [(≡Si—O)3VIII(OH2)], an intermediate that is often proposed in a Mars–van Krevelen type mechanism for partial oxidation of light alcohols. Oxidation of 2 under air produced the oxo-derivative [SbW9O33(tBuSiO)3VO]3– (3). In compound 2, the d2-electrons are localized in degenerated d(V) orbitals, whereas in the electronically analogous bireduced-[SbW9O33(tBuSiO)3VO]5–, 3·(2e), one electron is localized on d(V) orbital and the second one is delocalized on the polyoxotungstic framework, leading to a unique case of a bireduced heteropolyanion derivative with completely decoupled d1-V(IV) and d1-W(V). Our body of experimental results (EPR, magnetic measurements, spectroelectrochemical studies, Raman spectroscopy) and theoretical studies highlights (i) the role of the apical ligand coordination, i.e., thf (σ-donor) vs oxo (π-donor), in destabilizing or stabilizing the d(V) orbitals relative to the d(W) orbitals, and (ii) a geometrical distortion of the O3VO entity that causes a splitting of the degenerated orbitals and the stabilization of one d(V) orbital in the bireduced compound 3·(2e).
    Mots-clés : E-POM, ERMMES, POLE 2.

2017



  • S. P. Babailov, E. V. Peresypkina, Y. Journaux, et K. E. Vostrikova, « Nickel(II) complex of a biradical: Structure, magnetic properties, high NMR temperature sensitivity and moderately fast molecular dynamics », Sensors and Actuators B: Chemical, vol. 239, p. 405-412, 2017.


  • A. Conte-Daban, V. Borghesani, S. Sayen, E. Guillon, Y. Journaux, G. Gontard, L. Lisnard, et C. Hureau, « Link between Affinity and Cu(II) Binding Sites to Amyloid-β Peptides Evaluated by a New Water-Soluble UV–Visible Ratiometric Dye with a Moderate Cu(II) Affinity », Analytical Chemistry, vol. 89, nᵒ 3, p. 2155-2162, févr. 2017.
    Résumé : Being able to easily determine the Cu(II) affinity for biomolecules of moderate affinity is important. Such biomolecules include amyloidogenic peptides, such as the well-known amyloid-β peptide involved in Alzheimer’s disease. Here, we report the synthesis of a new water-soluble ratiometric Cu(II) dye with a moderate affinity (109 M–1 at pH 7.1) and the characterizations of the Cu(II) corresponding complex by X-ray crystallography, EPR, and XAS spectroscopic methods. UV–vis competition was performed on the Aβ peptide as well as on a wide series of modified peptides, leading to an affinity value of 1.6 × 109 M–1 at pH 7.1 for the Aβ peptide and to a coordination model for the Cu(II) site within the Aβ peptide that agrees with the one mostly accepted currently.
    Mots-clés : ERMMES, POLE 2.


  • A. Flambard, A. Sugahara, S. De, M. Okubo, A. Yamada, et R. Lescouëzec, « Probing the local structure of Prussian blue electrodes by 113Cd NMR spectroscopy », Dalton Transactions, vol. 46, nᵒ 19, p. 6159-6162, mai 2017.
    Résumé : We demonstrate that 113Cd NMR is a potent technique to monitor the local electronic and structural states of the Prussian blue electrode during Li+ intercalation, providing an atomic-scale insight into the reaction mechanism.
    Mots-clés : ERMMES, POLE 2.
    Pièce jointe Full Text PDF 354.8 ko (source)


  • J. - R. Jiménez, M. Tricoire, D. Garnier, L. - M. Chamoreau, J. von Bardeleben, Y. Journaux, Y. Li, et R. Lescouëzec, « A new {Fe4Co4} soluble switchable nanomagnet encapsulating Cs+: enhancing the stability and redox flexibility and tuning the photomagnetic effect. », Dalton Transactions, vol. 46, nᵒ 44, p. 15549–15557, nov. 2017.
    Résumé : We report a new cyanide-bridged Cs⊂{Fe4Co4} box, a soluble model of photomagnetic Prussian blue analogues (PBAs). The Cs+ ion has a high affinity for the box and can replace the K+ ion in the preformed K-cube. This exchange is kinetically impeded at room temperature but is accelerated by heating and using the 18-crown-6 ether. The inserted Cs+ ion confers a high robustness to the cube, which withstands boiling, as shown by variable-temperature NMR studies. The stability of this model complex in solution allows the probing of the electronic interaction between the alkali ion and the cyanide cage by using various techniques. These interactions are known to play a role in the photomagnetic behaviour of PBAs. Firstly, the 133Cs NMR spectroscopy proves that there is an electronic communication between the encapsulated alkali ion and the cyanide cage. The measured up-field signal, observed at ca. −200 ppm at 300 K, reveals that a certain amount of spin density is transferred through the bonds from the paramagnetic Co(II) ion to the encapsulated cation. Secondly, cyclovoltammetric studies show that the nature of the inserted ions affects the redox properties of the cage and influences the electronic communication between the metal ions. However, the differences in the electrochemical properties of the K-cube and the Cs-cube remain moderate. As the switching properties are influenced by the redox potential of the Fe and Co centers, similar photomagnetic behaviour is observed, with both of them being highly photomagnetic. This result contrasts strikingly with previous studies on the 3D polymeric PBAs, where the PBAs with a high amount of Cs+ show poor photomagnetic behaviour. In that case, cooperative behaviour likely influences the switching properties. Finally, EPR spectroscopy shows that the K-cube is more anisotropic than the Cs-cube. This difference is reflected in the changes occurring in the slow magnetic relaxation (single molecule magnet behaviour) observed in the two cubes.
    Mots-clés : ERMMES, POLE 2.


  • S. B. Moussa, H. Bachouâ, M. Gruselle, P. Beaunier, A. Flambard, et B. Badraoui, « Hybrid organic-inorganic materials based on hydroxyapatite structure », Journal of Solid State Chemistry, vol. 248, p. 171-177, avr. 2017.
    Résumé : The present article details the formation of calcium hydroxyapatite synthesized by the hydrothermal way, in presence of glycine or sarcosine. The presence of these amino-acids during the synthetic processes reduces the crystalline growthing through the formation of hybrid organic-inorganic species The crystallite sizes are decreasing and the morphology is modified with the increase of the amino-acid concentration.
    Mots-clés : ARC, ERMMES, Glycine, Hydrothermal synthesis, Hydroxyapatite, POLE 1, POLE 2, Sarcosine.


  • K. Shankar, A. Mondal, Y. Li, Y. Journaux, et J. B. Baruah, « Hydroxide-Bridged Mixed-Valence Tetranuclear Cobalt 4-Nitrophenol Inclusion Complex Showing Single Molecule Magnet Property », ChemistrySelect, vol. 2, nᵒ 26, p. 7792-7798, 2017.
    Résumé : Two tetranuclear hydroxide-bridged mixed-valence cobalt complexes, one having 4-nitrophenolate anions and other having 4-nitrophenol as guest, namely [(μ2-dea)2(phen)2Co2(μ3-OH)2Co2(phen)2](np)4•H2O (1), [(μ2-dea)2(phen)2Co2(μ3-OH)2 Co2(phen)2]Cl4•2Hnp•9H2O (2) (Hnp=4-nitrophenol, phen=1,10-phenanthroline, dea=di-deprotonated diethanolamine) were synthesized and structurally characterized. Complex cation of these two complexes are based on Co4O4(OH)2 units where two cobalt ions are in Co2+ and other two are in Co3+ oxidation states. Reaction of same set of reactants namely phen, Hnp and diethanolamine with cobalt nitrate in presence or absence of hydrochloric acid resulted complex 1 and 2 respectively. The two triply-bridging hydroxides of complex 1 are in identical environment, but the complex 2 has two triply-bridging hydroxides in slightly different environments having differences in Co-O(hydroxide) bond distances around them. Complex 2 is ferromagnetic and shows field induced Single Molecule Magnets (SMM) behavior.
    Mots-clés : ERMMES, Hydroxide-bridged complex, Magnetic properties, POLE 2, Single molecule magnet, Tetranuclear cobalt complex.

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2016

2015



  • M. Castellano, R. Ruiz-García, J. Cano, J. Ferrando-Soria, E. Pardo, F. R. Fortea-Pérez, S. - E. Stiriba, W. P. Barros, H. O. Stumpf, L. Cañadillas-Delgado, J. Pasán, C. Ruiz-Pérez, G. de Munno, D. Armentano, Y. Journaux, F. Lloret, et M. Julve, « Metallosupramolecular approach toward multifunctional magnetic devices for molecular spintronics », Coordination Chemistry Reviews, vol. 303, p. 110-138, nov. 2015.
    Résumé : The work presented in this review constitutes a successful extension of our group's research on the chemistry and physics of dinuclear copper(II) metallacyclophanes with aromatic polyoxalamide ligands. The design and synthesis of metallacyclic complexes that contain multiple electro- and photoactive (either metal- or ligand-based) spin carriers and the study of their spectroscopic and magnetic properties as well as their redox and photochemical activity are of large interest in the multidisciplinary field of metallosupramolecular chemistry. In doing this, a ligand design approach has been followed which is based on the copper(II)-mediated self-assembly of bis(oxamato) bridging ligands possessing potentially electro- and photoactive, extended π-conjugated aromatic spacers. This strategy benefits from the inherent physical and chemical properties of aromatic organic molecules by functionalizing them with two oxamato donor groups to get dinucleating ligands that are then able to self-assemble with square planar CuII ions affording the targeted oxamato-based dicopper(II) metallacyclophanes. The organic functionalization in this new class of metallacyclic systems constitutes a unique example of ligand design for the supramolecular control of the structure and magnetic properties, as well as the electro- and photochemical activities. This novel class of oxamato-based dicopper(II) metallacyclophanes provides excellent models for the fundamental study on through-ligand long-distance and redox- or photo-triggered electron exchange phenomena, which are two central topics in molecular magnetism and molecular electronics. Using these simple dinuclear metallacyclic complexes as dynamic chemical systems to perform specific and selective tasks under the control of an external (electro- and/or photochemical) stimulus that switches “ON” and “OFF” their electronic (optical and/or magnetic) properties may have an enormous impact in several domains of molecular nanoscience. Hence, oxamato-based dicopper(II) metallacyclophanes appear as very promising candidates to get multifunctional magnetic devices controlling and facilitating the spin communication (“molecular magnetic couplers” and “molecular magnetic wires”) or exhibiting charge storage (“molecular magnetic capacitors”) and bistable spin behavior (“molecular magnetic rectifiers” and “molecular magnetic switches”) for potential applications in information processing and storage in the emerging areas of molecular spintronics and quantum computing. Moreover, because of the potential high affinity for a variety of metal surfaces through the free carbonyl-oxygen atoms of the oxamate groups, they are very appealing candidates for the study of coherent electron transport through single molecules.
    Mots-clés : Electrochemistry, ERMMES, Ligand design, Magnetochemistry, Metallacyclic complexes, Metallosupramolecular chemistry, photochemistry, POLE 2.
    Note Note
    <p>Castellano, Maria Ruiz-Garcia, Rafael Cano, Joan Ferrando-Soria, Jesus Pardo, Emilio Fortea-Perez, Francisco R. Stiriba, Salah-Eddine Barros, Wdeson P. Stumpf, Humberto O. Canadillas-Delgado, Laura Pasan, Jorge Ruiz-Perez, Catalina de Munno, Giovanni Armentano, Donatella Journaux, Yves Lloret, Francesc Julve, Miguel<br />Fortea-Perez, Francisco/B-7848-2014;<br />Pardo, Emilio/0000-0002-1394-2553; Armentano, Donatella/0000-0002-8502-8074</p>


  • D. de Bellefeuille, M. Orio, A. L. Barra, A. Aukauloo, Y. Journaux, C. Philouze, X. Ottenwaelder, et F. Thomas, « Redox Noninnocence of the Bridge in Copper(II) Salophen and Bis(oxamato) Complexes », Inorganic Chemistry, vol. 54, nᵒ 18, p. 9013-9026, sept. 2015.
    Résumé : Two square-planar copper(II) complexes of 1,2-bis(2-hydroxy-3,5-di-tert-butylbenzimino)-4,5-bis-(dimethylamino)benzene (1) and N-[4,5-bis(dimethylamino)-2-(oxalylamino)benzene]oxamate (2(2-)) were prepared. The crystal structures of the proligands H2L1 and Et2H2L2, as well as the corresponding complexes, are reported. The proligands each display a one-electron-oxidation wave, which is assigned to oxidation of the bis(dimethylamino)benzene moiety into a pi radical. Complexes 1 and 2(2-) exhibit reversible one-electron-oxidation waves in their cyclic voltammograms (E-1/2(1) = 0.14 and E-1/2(2) = 0.31 V for 1 and E-1/2(1) = 0.47 V vs Fc(+)/Fc for 2(2-)). The first process corresponds to oxidation of the bis(dimethylamino)benzene central ring into a pi radical, while the second process for 1 is ascribed to oxidation of the pi radical into an alpha-diiminoquinone. The one-electron-oxidized species 1(+) and 2(-) exhibit intense visible near-IR absorptions, which are diagnostic of pi radicals. They display a triplet signal in their electron paramagnetic resonance spectra, which stem from magnetic coupling between the ligand-radical spin and the copper(II) spin. The zero-field-splitting parameters are larger for 2(-) than 1(+) because of greater delocalization of the spin density onto the coordinated amidato N atoms. Density functional theory calculations support a pi-radical nature of the one-electron-oxidized complexes, as well as S = 1 ground spin states. The electrogenerated 1(2+) comprises a closed-shell diiminoquinone ligand coordinated to a copper(II) metal center. Both 1 and 2 catalyze the aerobic oxidation of benzyl alcohol, albeit with different yields.
    Mots-clés : ERMMES, POLE 2.
    Note Note
    <p>de Bellefeuille, David Orio, Maylis Barra, Anne-Laure Aukauloo, Ally Journaux, Yves Philouze, Christian Ottenwaelder, Xavier Thomas, Fabrice<br />Orio, Maylis/J-6355-2015; Ottenwaelder, Xavier/J-1801-2012<br />Orio, Maylis/0000-0002-9317-8005; Ottenwaelder, Xavier/0000-0003-4775-0303</p>
    Note Note
    <p>de Bellefeuille, David Orio, Maylis Barra, Anne-Laure Aukauloo, Ally Journaux, Yves Philouze, Christian Ottenwaelder, Xavier Thomas, Fabrice<br />Orio, Maylis/J-6355-2015; Ottenwaelder, Xavier/J-1801-2012<br />Orio, Maylis/0000-0002-9317-8005; Ottenwaelder, Xavier/0000-0003-4775-0303</p>


  • T. Grancha, M. Mon, F. Lloret, J. Ferrando-Soria, Y. Journaux, J. Pasan, et E. Pardo, « Double Interpenetration in a Chiral Three-Dimensional Magnet with a (10,3)-a Structure », Inorganic Chemistry, vol. 54, nᵒ 18, p. 8890-8892, sept. 2015.
    Résumé : A unique chiral three-dimensional magnet with an overall racemic double-interpenetrated (10,3)-a structure of the formula [(S)-(1-PhEt)-

    Me3N](4)[Mn4Cu6(Et(2)pma)(12)] (DMSO)(3)]center dot 3DMS center dot 5H(2)O (1; Et(2)pma = N-2,6-diethylphenyloxamate) has been synthesized by the self-assembly of a mononuclear copper(II) complex acting as a metalloligand toward Mn-II ions in the presence of a chiral cationic auxiliary, constituting the first oxamato-based chiral coordination polymer exhibiting long-range magnetic ordering.
    Mots-clés : ERMMES, POLE 2.
    Note Note
    <p>Grancha, Thais Mon, Marta Lloret, Francesc Ferrando-Soria, Jesus Journaux, Yves Pasan, Jorge Pardo, Emilio<br />Pardo, Emilio/C-9519-2013;<br />Pardo, Emilio/0000-0002-1394-2553</p>


  • A. Paquirissamy, A. R. Ruyack, A. Mondal, Y. Li, R. Lescouëzec, C. Chanéac, et B. Fleury, « Versatile nano-platforms for hybrid systems: expressing spin-transition behavior on nanoparticles », Journal of Materials Chemistry C, vol. 3, nᵒ 14, p. 3350-3355, 2015.


  • Y. Prado, N. Daffé, A. Michel, T. Georgelin, N. Yaacoub, J. M. Grenèche, F. Choueikani, E. Otero, P. Ohresser, M. A. Arrio, C. Cartier-dit-Moulin, P. Sainctavit, B. Fleury, V. Dupuis, L. Lisnard, et J. Fresnais, « Enhancing the magnetic anisotropy of maghemite nanoparticles via the surface coordination of molecular complexes », Nature Communications, vol. 6, déc. 2015.
    Résumé : Superparamagnetic nanoparticles are promising objects for data storage or medical applications. In the smallest-and more attractive-systems, the properties are governed by the magnetic anisotropy. Here we report a molecule-based synthetic strategy to enhance this anisotropy in sub-10-nm nanoparticles. It consists of the fabrication of composite materials where anisotropic molecular complexes are coordinated to the surface of the nanoparticles. Reacting 5 nm gamma-Fe2O3 nanoparticles with the [Co-II(TPMA)Cl-2] complex (TPMA: tris(2-pyridylmethyl) amine) leads to the desired composite materials and the characterization of the functionalized nanoparticles evidences the successful coordination-without nanoparticle aggregation and without complex dissociation-of the molecular complexes to the nanoparticles surface. Magnetic measurements indicate the significant enhancement of the anisotropy in the final objects. Indeed, the functionalized nanoparticles show a threefold increase of the blocking temperature and a coercive field increased by one order of magnitude.
    Mots-clés : ERMMES, POLE 2.
    Note Note
    <p>Prado, Yoann Daffe, Nieli Michel, Aude Georgelin, Thomas Yaacoub, Nader Greneche, Jean-Marc Choueikani, Fadi Otero, Edwige Ohresser, Philippe Arrio, Marie-Anne Cartier-dit-Moulin, Christophe Sainctavit, Philippe Fleury, Benoit Dupuis, Vincent Lisnard, Laurent Fresnais, Jerome</p>


  • Y. Wang, P. - A. Deyris, T. Caneque, F. Blanchard, Y. Li, F. Bigi, R. Maggi, S. Blanchard, G. Maestri, et M. Malacria, « A Simple Synthesis of Triangular All-Metal Aromatics Allowing Access to Isolobal All-Metal Heteroaromatics », Chemistry – A European Journal, vol. 21, nᵒ 35, p. 12271-12274, 2015.
    Résumé : A simple synthetic method allows the one-pot assembly of C3-symmetric, 44-core-valence-electron, triangular Pd or Pt clusters and their heterobimetallic mixed Pd/Pt analogues. These mixed metal complexes are the first examples of stable triangular all-metal heteroaromatics. In contrast to traditional heteroaromatic molecules formed combining main-group elements, they actually retain structural and electronic features of their homonuclear analogues.
    Mots-clés : aromaticity, cluster compounds, E-POM, ERMMES, Heterocycles, MACO, Metallacycles, POLE 1, POLE 2.


  • H. Yang, S. Masse, M. Rouelle, E. Aubry, Y. Li, C. Roux, Y. Journaux, L. Li, et T. Coradin, « Magnetically recoverable iron oxide–hydroxyapatite nanocomposites for lead removal », International Journal of Environmental Science and Technology, vol. 12, nᵒ 4, p. 1173-1182, avr. 2015.
    Résumé : Magnetite–hydroxyapatite nanocomposites were prepared by in situ precipitation of the calcium phosphate phase in an iron oxide colloidal suspension. Homogeneous magnetic powders were obtained with iron oxide content up to 50 wt%, without perturbation of the magnetite structure nor formation of additional calcium phosphates. The surface area of the composite powder was significantly increased after incorporation of magnetite due to the better apatite particle dispersion. This results in an increased available reactive surface, favoring lead sorption and hydroxypyromorphite precipitation, both leading to an enhanced lead removal capacity of the composite materials. The magnetic properties of magnetite nanocrystals were preserved upon association with hydroxyapatite. Full recovery of the composite powder after lead removal could be achieved using a simple magnet at a relatively low iron oxide content (20 wt%). This indicates a strong interaction between hydroxyapatite and magnetite particles within the composite powder. The procedure is simple, easily scalable and involves only environmental friendly materials.
    Mots-clés : ERMMES, POLE 2.

2014


  • M. Castellano, W. P. Barros, A. Acosta, M. Julve, F. Lloret, Y. Li, Y. Journaux, G. De Munno, D. Armentano, R. Ruiz-Garcia, et J. Cano, « Dicopper(II) Anthraquinophanes as Multielectron Reservoirs for Oxidation and Reduction: A Joint Experimental and Theoretical Study », Chemistry a European Journal, vol. 20, nᵒ 43, p. 13965-13975, oct. 2014.
    Résumé : Two new dinuclear copper(II) metallacyclophanes with 1,4-disubstituted 9,10-anthraquinonebis(oxamate) bridging ligands are reported that can reversibly take and release electrons at the redox-active ligand and metal sites, respectively, to give the corresponding mono-and bis(semiquinonate and/or catecholate) Cu-2(II) species and mixedvalent Cu-II/Cu-III and high-valent Cu-2(III) ones. Density functional calculations allow us to give further insights on the dual ligand-and metal-based character of the redox processes in this novel family of antiferromagnetically coupled dicopper(II) anthraquinophanes. This unique ability for charge storage could be the basis for the development of new kinds of molecular spintronic devices, referred to as molecular magnetic capacitors (MMCs).
    Mots-clés : chemistry, clusters, copper, Density functional calculations, electron-transfer, ERMMES, ligand, Magnetic properties, molecular electronics, POLE 2, quantum cellular-automata, quinones, redox properties, transition-metal-complexes.

  • B. Matt, K. M. Pondman, S. J. Asshoff, B. ten Haken, B. Fleury, et N. Katsonis, « Soft Magnets from the Self-Organization of Magnetic Nanoparticles in Twisted Liquid Crystals », Angewandte Chemie-International Edition, vol. 53, nᵒ 46, p. 12446-12450, nov. 2014.
    Résumé : Organizing magnetic nanoparticles into long-range and dynamic assemblies would not only provide new insights into physical phenomena but also open opportunities for a wide spectrum of applications. In particular, a major challenge consists of the development of nanoparticle-based materials for which the remnant magnetization and coercive field can be controlled at room temperature. Our approach consists of promoting the self-organization of magnetic nanoparticles in liquid crystals (LCs). Using liquid crystals as organizing templates allows us to envision the design of tunable self-assemblies of magnetic nanoparticles, because liquid crystals are known to reorganize under a variety of external stimuli. Herein, we show that twisted liquid crystals can be used as efficient anisotropic templates for superparamagnetic nanoparticles and demonstrate the formation of hybrid soft magnets at room temperature.
    Mots-clés : coatings, ERMMES, POLE 2, Self-assembly.

  • A. Mondal, Y. Li, L. - M. Chamoreau, M. Seuleiman, L. Rechignat, A. Bousseksou, M. - L. Boillot, et R. Lescouëzec, « Photo- and thermo-induced spin crossover in a cyanide-bridged {(Mo2Fe2II)-Fe-V} rhombus molecule », Chemical Communications, vol. 50, nᵒ 22, p. 2893-2895, 2014.
    Résumé : The self-assembly of [Mo-V(CN)(8)](3-) and [Fe-II(bik)(2)(S)(2)](2+) affords a cyanide-bridged {(Mo2Fe2II)-Fe-V} rhombus molecule that shows photo-magnetic effect under laser light irradiation at low temperature and exhibits thermo-induced spin crossover near ambient temperature.
    Mots-clés : behavior, complexes, crystal, ERMMES, POLE 2.

  • R. Tirfoin, L. - M. Chamoreau, Y. Li, B. Fleury, L. Lisnard, et Y. Journaux, « Synthesis, structure and magnetic properties of phenylhydroxamate-based coordination clusters », Dalton Transactions, vol. 43, nᵒ 44, p. 16805-16817, 2014.
    Résumé : The strategic recombination of preformed coordination clusters in the presence of polymodal bridging ligands has successfully led to the characterisation of five new compounds of structural and magnetic interest. Indeed using the dinuclear complex [M-2(H2O)(piv)(4)(Hpiv)(4)] (M = Co, Ni; Hpiv = pivalic acid) as starting material and reacting it with phenylhydroxamic acid (H(2)pha) has yielded the four tetrametallic coordination clusters [Co-4(Hpha)(2)(piv)(6)(Hpiv)(4)] (1), [Ni-4(Hpha)(2)(piv)(6)(Hpiv)(2)(DMF)(2)] (2), [Co-4(Hpha)(2)(piv)(6)(EtOH)(2)(H2O)(2)] (3), [Ni-4(Hpha)(2)(piv)(6)(EtOH)(2)(H2O)(2)] (4) and the hexanuclear complex [Co-6(Hpha)(4)(piv)(8)(EtOH)(2)]center dot EtOH (5). All the compounds have been structurally characterised revealing a particular binding mode for the hydroxamate ligand. The study of their magnetic properties has been performed and the modelling of these properties has been done using the appropriate hamiltonians for each compound. The experimental data and their modelling show non-zero spin ground states for compounds 4 and 5.
    Mots-clés : ERMMES, POLE 2.


  • A. - R. Tomsa, Y. Li, S. Blanchard, P. Herson, K. Boubekeur, P. Gouzerh, et A. Proust, « Oxo-Centered Trinuclear Chromium(III) Complexes with Both Carboxylate and Amidoximate Ligands », Journal of Cluster Science, vol. 25, nᵒ 3, p. 825-838, 2014.
    Mots-clés : Amidoximes, Carboxylate, catalysis, Chromium, E-POM, ERMMES, Inorganic Chemistry, Magnetism, Physical Chemistry, POLE 2, POM, structure.

2013



  • N. Baumgärtel, A. Flambard, F. H. Köhler, et R. Lescouëzec, « Paramagnetic Hexacyanometalates. The Diversity of Spin Distribution Studied by <sup>13</sup> C and <sup>15</sup> N MAS NMR Spectroscopy », Inorganic Chemistry, vol. 52, nᵒ 21, p. 12634-12644, nov. 2013.


  • M. Castellano, F. R. Fortea-Pérez, A. Bentama, S. - E. Stiriba, M. Julve, F. Lloret, G. De Munno, D. Armentano, Y. Li, R. Ruiz-García, et J. Cano, « Dicopper(II) Metallacyclophanes with Oligo(p-phenylene-ethynylene) Spacers: Experimental Foundations and Theoretical Predictions on Potential Molecular Magnetic Wires », Inorganic Chemistry, vol. 52, nᵒ 13, p. 7645-7657, 2013.
    Résumé : Two novel double-stranded dicopper(II) metallacyclophanes of formula (nBu4N)4[Cu2(dpeba)2]·4MeOH·2Et2O (1) and (nBu4N)4[Cu2(tpeba)2]·12H2O (2) have been prepared by the CuII-mediated self-assembly of the rigid (?rod-like?) bridging ligands N,N?-4,4?-diphenylethynebis(oxamate) (dpeba) and N,N?-1,4-di(4-phenylethynyl)phenylenebis(oxamate) (tpeba), respectively. Single crystal X-ray diffraction analysis of 1 confirms the presence of a dicopper(II)tetraaza[3.3]4,4?-diphenylethynophane metallacyclic structure featuring a very long intermetallic distance between the two square planar CuII ions [r = 14.95(1) Å]. The overall parallel-displaced π-stacked conformation of the two nearly planar para substituted diphenylethyne spacers [dihedral angle (?) of 7.8(1)°] leads to important deviations from the perpendicular orientation of the copper mean basal planes with respect to the facing benzene planes [dihedral angles (?) of 56.4(1) and 58.4(1)°]. X-band EPR spectra together with variable-temperature magnetic susceptibility and variable-field magnetization measurements of 1 and 2, both in solution and in the solid state, show the occurrence of a non-negligible, moderate to weak intramolecular antiferromagnetic coupling [?J = 3.9?4.1 (1) and 0.5?0.9 cm?1 (2); H = ?JS1·S2 with S1 = S2 = SCu = 1/2]. Density functional calculations on the BS singlet (S = 0) and triplet (S = 1) spin states of the model complexes 1 and 2 with an ideal orthogonal molecular geometry (? = 0° and ? = 90°) support the occurrence of a spin polarization mechanism for the propagation of the exchange interaction between the two unpaired electrons occupying the dxy orbital of each square planar CuII ion through the predominantly π-type orbital pathway of the double p-diphenylethyne (1) and di(phenylethynyl)phenylene spacers (2). Time-dependent density functional calculations reproduce the observed bathochromic shift of the main intraligand (IL) π?π* transition in the electronic absorption spectra of 1 and 2 [?1 = 308 (1) and 316 nm (2)]. In the series of orthogonal model complexes 1?5 with linear oligo(p-phenylene-ethynylene) (OPE) spacers, ?C6H4(C≡CC6H4)n? (n = 1?5), a linear increase of the IL π?π* transition energy with the reciprocal of the intermetallic distance is theoretically predicted [?max = 1.99 ? 104 + 2.15 ? 105 (1/r) (S = 0) or ? = 2.01 ? 104 + 2.18 ? 105 (1/r) (S = 1)], which clearly indicates that the effective π-conjugation length increases with the number of phenylethyne repeating units. This is accompanied by an exponential decay of the antiferromagnetic coupling with the intermetallic distance [?J = 1.08 ? 103 exp(?0.31r)], which supports the ability of the extended π-conjugated OPEs to mediate the exchange interaction between the unpaired electrons of the two CuII centers with intermetallic distances in the range of 1.5?4.3 nm. Further developments may be then envisaged for this new family of oxamato-based dicopper(II) oligo-p-phenylethynophanes on the basis of the unique ligand capacity to act as a molecular antiferromagnetic wire.
    Mots-clés : ERMMES, POLE 2.


  • M. Castellano, R. Ruiz-García, J. Cano, M. Julve, F. Lloret, Y. Journaux, G. De Munno, et D. Armentano, « Multielectron transfer in a dicopper(ii) anthraquinophane », Chemical Communications, vol. 49, nᵒ 34, p. 3534, 2013.


  • N. Dia, L. Lisnard, Y. Prado, A. Gloter, O. Stéphan, F. Brisset, H. Hafez, Z. Saad, C. Mathonière, L. Catala, et T. Mallah, « Synergy in Photomagnetic/Ferromagnetic Sub-50 nm Core-Multishell Nanoparticles », Inorganic Chemistry, vol. 52, nᵒ 18, p. 10264-10274, sept. 2013.
    Résumé : Based on nickel hexacyanidochromate and cobalt hexacyanidoferrate Prussian blue analogues, two series of photomagnetic/ferromagnetic sub-50 nm core multishell coordination nanoparticles have been synthesized in a surfactant-free one-pot multistep procedure with good control over the dispersity (10% standard deviation) and good agreement with the targeted size at each step. The composition and the valence state of each shell have been probed by different techniques that have revealed the predominance of CoII-NC-FeIII pairs in a series synthesized without alkali while CoIII-NC-FeII photoswitchable pairs have been successfully obtained in the photoactive coordination nanoparticles by control of Cs+ insertion. When compared, the photoinduced behavior of the latter compound is in good agreement with that of the model one. Exchange coupling favors a uniform reversal of the magnetization of the heterostructured nanoparticles, with a large magnetization brought by a soft ferromagnetic shell and a large coercivity due to a harder photomagnetic shell. Moreover, a persistent increase of the photoinduced magnetization is observed for the first time up to the ordering temperature (60 K) of the ferromagnetic component because of a unique synergy.
    Mots-clés : ERMMES, MMMAX, POLE 2.


  • R. Djeda, C. Desmarets, L. - M. Chamoreau, Y. Li, Y. Journaux, G. Gontard, et H. Amouri, « Meso-Helicates with Rigid Angular Tetradentate Ligand: Design, Molecular Structures, and Progress Towards Self-Assembly of Metal–Organic Nanotubes », Inorganic Chemistry, vol. 52, nᵒ 22, p. 13042-13047, 2013.

  • J. Ferrando-Soria, M. Castellano, R. Ruiz-Garcia, J. Cano, M. Julve, F. Lloret, C. Ruiz-Perez, J. Pasan, L. Canadillas-Delgado, D. Armentano, Y. Journaux, et E. Pardo, « Dicopper(II) Metallacyclophanes with Electroswitchable Polymethyl-Substituted para-Phenylene Spacers », Chemistry-a European Journal, vol. 19, nᵒ 36, p. 12124-12137, sept. 2013.
    Résumé : Double-stranded anionic dinuclear copper(II) metallacyclic complexes of the paracyclophane type [Cu2L2](4-) have been prepared by the Cu-II-mediated self-assembly of different para-phenylenebis(oxamato) bridging ligands with either zero-, one-, or four-electron-donating methyl substituents (L=N,N-para-phenylenebis(oxamate) (ppba; 1), 2-methyl- N,N-para-phenylenebis(oxamate) (Meppba; 2), and 2,3,5,6-tetramethyl- N,N-para-phenylenebis(oxamate) (Me(4)ppba; 3)). These complexes have been isolated as their tetra-n-butylammonium (1a-3a), lithium(I) (1b-3b), and tetraphenylphosphonium salts (1c-3c). The X-ray crystal structures of 1a and 3c show a parallel-displaced -stacked conformation with a smaller deviation from perpendicularity between the two benzene rings and the basal planes of the square planar Cu-II ions when increasing the number of methyl substituents (average dihedral angles (phi) of 58.72(7) and 73.67(5)degrees for 1a and 3c, respectively). Variable-temperature (2.0-300K) magnetic-susceptibility measurements show an overall increase of the intramolecular antiferromagnetic coupling with the number of methyl substituents onto the para-phenylene spacers (-J=75-95, 100-124, and 128-144cm(-1) for 1a-c, 2a-c, and 3a-c, respectively; H=-JS(1)xS(2)). Cyclic voltammetry (CV) measurements show a reversible one-electron oxidation of the double polymethyl-substituted para-phenylenediamidate bridging skeleton at a relatively low formal potential that decreases with the number of methyl substituents (E-1=+0.33, +0.24, and +0.15V vs. SCE for 1-3, respectively). The monooxidized dicopper(II) -radical cation species 3 prepared by the chemical oxidation of 3 with bromine exhibits intense metal-to-ligand charge-transfer (MLCT) transitions in the visible and near-IR ((max)=595 and 875nm, respectively) regions together with a rhombic EPR signal with a seven-line splitting pattern due to hyperfine coupling with the nuclear spin of the two Cu-II ions. Density functional (DF) calculations for 3 evidence a characteristic iminoquinonoid-type short-long-short alternating sequence of CN and CC bonds for both tetramethyl-para-phenylenediamidate bridges and a large amount of spin density of negative sign mainly delocalized along each of the four benzene C atoms directly attached to the amidate N atoms, which is in

    agreement with a fully delocalized -stacked monoradical ligand description. Hence, the spins of the two Cu-II ions (S-Cu=1/2) that are antiparallel aligned in 3 (OFF state) become parallel in 3 (ON state). Further developments may be then envisaged for this new permethylated dicopper(II) paracyclophane with a redox noninnocent ligand as a prototype for molecular magnetic electroswitch.
    Mots-clés : Bridging ligands, copper, copper(ii) metallacyclophane, Density functional calculations, electron-transfer, ERMMES, Magnetic properties, Metallacycles, MMMAX, POLE 2.


  • M. Gruselle, Y. Li, N. Ovanesyan, V. Makhaev, G. Shilov, F. Mushenok, C. Train, et S. Aldoshin, « (S)-(−)-(2-MeBu)N(Pr)2MeI Salt as Template in the Enantioselective Synthesis of the Enantiopure Two-dimensional (S)-(−)-(2-MeBu)N(Pr)2Me[ΛMnΔCr(C2O4)3] Ferromagnet », Chirality, vol. 25, nᵒ 8, p. 444–448, 2013.
    Résumé : We describe herein the synthesis of (rac)- or enantiopure (S)-(−)-(2-MeBu)N(Pr)2MeI ammonium salts. These racemic and enantiopure ammonium salts were used as cationic templates to obtain new two-dimensional (2D) ferromagnets [(rac)-(2-MeBu)N(Pr)2Me][MnCr(C2O4)3] and [(S)-(−)-(2-MeBu)N(Pr)2Me][ΔMnΛ nCr(C2O4)3]. The absolute configuration of the hexacoordinated Cr(III) metallic ion in the enantiopure 2D network was determined by a circular dichroism measurement. The structure of [(2-MeBu)N(Pr)2Me][MnCr(C2O4)3], established by single crystal X-ray diffraction, belongs to the chiral P63 space group. According to direct current (dc) magnetic measurements, these compounds are ferrromagnets with a temperature Tc = 6°K. Chirality 25:444–448, 2013. © 2013 Wiley Periodicals, Inc.
    Mots-clés : 2D chiral networks, ammonium salts, ARC, ERMMES, ferromagnets, MMMAX, POLE 1, POLE 2.

  • A. Mondal, L. - M. Chamoreau, Y. Li, Y. Journaux, M. Seuleiman, et R. Lescouezec, « WCo Discrete Complex Exhibiting Photo- and Thermo-Induced Magnetisation », Chemistry-a European Journal, vol. 19, nᵒ 24, p. 7682-7685, juin 2013.
    Mots-clés : chain, co, cobalt, crystal-structure, cyanide, cyanide ligand, electron-transfer, ERMMES, MMMAX, Photomagnetism, POLE 2, Tungsten.

  • A. Mondal, P. - I. Dassie, L. - M. Chamoreau, Y. Journaux, M. Julve, L. Lisnard, et R. Lescouëzec, « Combining Cyanometalates and Coordination Clusters: An Alternative Synthetic Route toward Original Molecular Materials », Crystal Growth & Design, vol. 13, nᵒ 10, p. 4190-4194, oct. 2013.
    Résumé : As an original synthetic route to molecular magnetic materials, we have reacted partially blocked cyanometalates with preformed coordination cluster. The association of the fac-[Fe(Tp)(CN)(3)](-) assembling metalloligand with the [Cu-3(OH)(pz)(3)](2+) trigonal cluster has afforded a novel coordination network where the trimetallic copper(II) nodes are linked by the iron(III) complexes into chains and by coordinating acetate into a two-dimensional framework.
    Mots-clés : anisotropy, chain, complexes, crystal-structures, cyanide, ERMMES, magnetic-properties, MMMAX, networks, new-generation, POLE 2, polymers, secondary building units.


  • A. Mondal, S. Durdevic, L. - M. Chamoreau, Y. Journaux, M. Julve, L. Lisnard, et R. Lescouëzec, « A cyanide and hydroxo-bridged nanocage: a new generation of coordination clusters », Chemical Communications, vol. 49, nᵒ 12, p. 1181, 2013.


  • A. Mondal, Y. Li, M. Seuleiman, M. Julve, L. Toupet, M. Buron-Le Cointe, et R. Lescouëzec, « On/Off Photoswitching in a Cyanide-Bridged {Fe <sub>2</sub> Co <sub>2</sub> } Magnetic Molecular Square », Journal of the American Chemical Society, vol. 135, nᵒ 5, p. 1653-1656, févr. 2013.

  • N. Pavlicek, C. Herranz-Lancho, B. Fleury, M. Neu, J. Niedenfuehr, M. Ruben, et J. Repp, « High-resolution scanning tunneling and atomic force microscopy of stereochemically resolved dibenzo[a,h]thianthrene molecules », Physica Status Solidi B-Basic Solid State Physics, vol. 250, nᵒ 11, p. 2424-2430, nov. 2013.
    Résumé : Recently, we reported on the bistable configurational switching of dibenzo[a,h]thianthrene (DBTH) molecules adsorbed on NaCl using combined low-temperature scanning tunneling and atomic force microscopy (STM/AFM). Here, we discuss the intra-molecular contrast in AFM images of the molecules as a function of the tip-molecule distance. Our experiments show that ridges in the frequency shift do not necessarily correlate with chemical bonds in this case of a non-planar molecule. To explain this finding we compare images acquired at different tip-molecule distances to the calculated electron density of the molecules obtained from density functional theory calculations (DFT). In addition, we analyze the probability of finding different configurations after adsorption onto the surface. DBTH molecules in two configurations probed by a CO-functionalized tip. Insets show AFM (left) and STM (right) images of a U molecule.
    Mots-clés : ERMMES, MMMAX, POLE 2.

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