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Publications

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2014



  • M. Ménand, S. Adam de Beaumais, L. - M. Chamoreau, E. Derat, S. Blanchard, Y. Zhang, L. Bouteiller, et M. Sollogoub, « Solid-State Hierarchical Cyclodextrin-Based Supramolecular Polymer Constructed by Primary, Secondary, and Tertiary Azido Interactions », Angewandte Chemie International Edition, vol. 53, nᵒ 28, p. 7238-7242, juill. 2014.
    Mots-clés : Azides, cyclodextrins, E-POM, GOBS, inclusion compounds, MACO, POLE 1, POLE 2, POLE 3, POLE 4, POLYMERES, supramolecular polymers.
    Pièce jointe


  • A. Müller et P. Gouzerh, « Capsules with Highly Active Pores and Interiors: Versatile Platforms at the Nanoscale », Chemistry - A European Journal, vol. 20, nᵒ 17, p. 4862-4873, avr. 2014.

  • C. Rinfray, S. Renaudineau, G. Izzet, et A. Proust, « A covalent polyoxomolybdate-based hybrid with remarkable electron reservoir properties », Chemical Communications, vol. 50, nᵒ 62, p. 8575-8577, août 2014.
    Résumé : A new polyoxomolybdate-based hybrid platform TBA(4)[PMo11O39-{Sn(p-C6H4I)}] is reported. The presence of a post-functionalisable iodo-aryl moiety allows the grafting of a ferrocenyl moiety onto the POM. The electrochemical characterisation shows the effect of molybdenum on the electron reservoir properties of POM-based hybrids, which are further enhanced upon the addition of an acid.
    Mots-clés : chemistry, clusters, derivatives, E-POM, Keggin, platforms, POLE 2, polymers, polyoxometalates synthesis, polyoxotungstates, post-functionalization, Ruthenium.


  • E. Salanouve, G. Bouzemame, S. Blanchard, E. Derat, M. Desage-El Murr, et L. Fensterbank, « Tandem C-H Activation/Arylation Catalyzed by Low-Valent Iron Complexes with Bisiminopyridine Ligands », Chemistry – A European Journal, vol. 20, nᵒ 16, p. 4754-4761, 2014.
    Résumé : Tandem CH activation/arylation between unactivated arenes and aryl halides catalyzed by iron complexes that bear redox-active non-innocent bisiminopyridine ligands is reported. Similar reactions catalyzed by first-row transition metals have been shown to involve substrate-based aryl radicals, whereas our catalytic system likely involves ligand-centered radicals. Preliminary mechanistic investigations based on spectroscopic and reactivity studies, in conjunction with DFT calculations, led us to propose that the reaction could proceed through an inner-sphere CH activation pathway, which is rarely observed in the case of iron complexes. This bielectronic noble-metal-like behavior could be sustained by the redox-active non-innocent bisiminopyridine ligands.
    Mots-clés : aryl halides, bis(imino)pyridine iron, bond activation, catalysis, CH activation, cross-coupling reactions, CH activation, direct arylation, direct functionalization, E-POM, ethylene polymerization catalysts, E_POM, IR spectroscopy, Iron, MACO, POLE 1, POLE 2, POM, redox-active ligands, reductive elimination, unactivated arenes.
    Pièce jointe


  • 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.

  • R. Villanneau, A. Roucoux, P. Beaunier, D. Brouri, et A. Proust, « Simple procedure for vacant POM-stabilized palladium (0) nanoparticles in water: structural and dispersive effects of lacunary polyoxometalates », Rsc Advances, vol. 4, nᵒ 50, p. 26491-26498, 2014.
    Résumé : Metallic palladium nanoparticles have been generated by hydrogenation with H-2 of solutions of several non organometallic Pd-II-derivatives of heteropolytungstates, at ambient temperature and atmospheric pressure. These nanoparticles have been characterized by various techniques: P-31 NMR and Raman spectroscopy, TEM (including cryogenic techniques), DLS, EDX and XPS. The present strategy ruled out the presence of ligands and/or stabilizing agents other than the lacunary polyoxometalates (POMs) used. This allows the evaluation of the true efficiency of the different vacant POMs for the stabilization of the nanoparticles.
    Mots-clés : E-POM, gold nanoparticles, hydrogen-peroxide, Keggin, metal nanoparticles, molecular-oxygen, nanocluster formation, oxidation, pd nanoparticles, photocatalytic reduction, POLE 2, recyclable catalysts.


  • M. Yaqub, J. J. Walsh, T. E. Keyes, A. Proust, C. Rinfray, G. Izzet, T. McCormac, et R. J. Forster, « Electron Transfer to Covalently Immobilized Keggin Polyoxotungstates on Gold », Langmuir, vol. 30, nᵒ 15, p. 4509-4516, avr. 2014.

2013



  • N. Bridonneau, L. - M. Chamoreau, P. P. Lainé, W. Wernsdorfer, et V. Marvaud, « A new versatile class of hetero-tetra-metallic assemblies: highlighting single-molecule magnet behaviour », Chemical Communications, vol. 49, nᵒ 82, p. 9476-9478, sept. 2013.
    Résumé : Hetero-tetra-metallic species based on hexanuclear assemblies [((valen)M1)Ln(OH2)2(μM2(CN)8)]22− (Ln = GdIII, TbIII; M1 = CuII, NiII and M2 = MoIV, WIV) and co-crystallized mononuclear complexes [M3(tpy)2]2+ (M3 = NiII, RuII, OsII) were identified, fully characterized, and shown to constitute a new class of single-molecule magnets.
    Mots-clés : E-POM, POLE 2.


  • J. Fortage, G. Dupeyre, F. Tuyèras, V. Marvaud, P. Ochsenbein, I. Ciofini, M. Hromadová, L. Pospísil, A. Arrigo, E. Trovato, F. Puntoriero, P. P. Lainé, et S. Campagna, « Molecular Dyads of Ruthenium(II)– or Osmium(II)–Bis(terpyridine) Chromophores and Expanded Pyridinium Acceptors: Equilibration between MLCT and Charge-Separated Excited States », Inorganic Chemistry, vol. 52, nᵒ 20, p. 11944-11955, oct. 2013.
    Résumé : The synthesis, characterization, redox behavior, and photophysical properties (both at room temperature in fluid solution and at 77 K in rigid matrix) of a series of four new molecular dyads (2–5) containing Ru(II)– or Os(II)–bis(terpyridine) subunits as chromophores and various expanded pyridinium subunits as electron acceptors are reported, along with the reference properties of a formerly reported dyad, 1. The molecular dyads 2–4 have been designed to have their (potentially emissive) triplet metal-to-ligand charge-transfer (MLCT) and charge-separated (CS) states close in energy, so that excited-state equilibration between these levels can take place. Such a situation is not shared by limit cases 1 and 5. For dyad 1, forward photoinduced electron transfer (time constant, 7 ps) and subsequent charge recombination (time constant, 45 ps) are evidenced, while for dyad 5, photoinduced electron transfer is thermodynamically forbidden so that MLCT decays are the only active deactivation processes. As regards 2–4, CS states are formed from MLCT states with time constants of a few dozens of picoseconds. However, for these latter species, such experimental time constants are not due to photoinduced charge separation but are related to the excited-state equilibration times. Comparative analysis of time constants for charge recombination from the CS states based on proper thermodynamic and kinetic models highlighted that, in spite of their apparently affiliated structures, dyads 1–4 do not constitute a homologous series of compounds as far as intercomponent electron transfer processes are concerned.
    Mots-clés : E-POM, POLE 2.

  • M. M. Lorion, B. Matt, S. Alves, A. Proust, G. Poli, J. Oble, et G. Izzet, « Versatile Post-functionalization of Polyoxometalate Platforms By Using An Unprecedented Range of Palladium-Catalyzed Coupling Reactions », Chemistry - A European Journal, vol. 19, nᵒ 38, p. 12607-12612, sept. 2013.
    Mots-clés : Allylic alkylation, clusters, cross-coupling, CSOB, dawson, E-POM, head groups, Heck reaction, hybrid, Keggin, organic-inorganic hybrids, Palladium, POLE 1, POLE 2, POLE 3, Polyoxometalates, polyoxotungstates, POM, ROCS, SSO, surfaces, surfactants.


  • B. Matt, J. Fize, J. Moussa, H. Amouri, A. Pereira, V. Artero, G. Izzet, et A. Proust, « Charge photo-accumulation and photocatalytic hydrogen evolution under visible light at an iridium(iii)-photosensitized polyoxotungstate », Energy & Environmental Science, vol. 6, nᵒ 5, p. 1504, 2013.


  • B. Matt, X. Xiang, A. L. Kaledin, N. Han, J. Moussa, H. Amouri, S. Alves, C. L. Hill, T. Lian, D. G. Musaev, G. Izzet, et A. Proust, « Long lived charge separation in iridium(III)-photosensitized polyoxometalates: synthesis, photophysical and computational studies of organometallic–redox tunable oxide assemblies », Chemical Science, vol. 4, nᵒ 4, p. 1737-1745, mars 2013.
    Résumé : Keggin and Dawson-type polyoxometalates (POMs) covalently grafted to heteroleptic cyclometalated iridium(iii) complexes (POM–[Ir] dyads) have been prepared by postfunctionalization of organosilyl and organotin POM derivatives. Electronic properties of these 4 photosensitized POM–[Ir] dyads were evaluated by
    Mots-clés : ARC, CSOB, E-POM, POLE 1, POLE 2, POLE 3, POM.


  • A. Parrot, G. Izzet, L. - M. Chamoreau, A. Proust, O. Oms, A. Dolbecq, K. Hakouk, H. El Bekkachi, P. Deniard, R. Dessapt, et P. Mialane, « Photochromic Properties of Polyoxotungstates with Grafted Spiropyran Molecules », Inorganic Chemistry, vol. 52, nᵒ 19, p. 11156-11163, oct. 2013.
    Résumé : The first systems associating in a single molecule polyoxotungstates (POTs) and photochromic organic groups have been elaborated. Using the (TBA)4[PW11O39{Sn(C6H4I)}] precursor, two hybrid organic?inorganic species where a spiropyran derivative (SP) has been covalently grafted onto a {PW11Sn} fragment via a Sonogashira coupling have been successfully obtained. Alternatively, a complex containing a silicotungstate {PW11Si2} unit connected to two spiropyran entities has been characterized. The purity of these species has been assessed using several techniques, including 1H and 31P NMR spectroscopy, mass spectrometry, and electrochemical measurements. The optical properties of the hybrid materials have been investigated both in solution and in the solid state. These studies reveal that the grafting of SPs onto POTs does not significantly alter the photochromic behavior of the organic chromophore in solution. In contrast, these novel hybrid SP?POT materials display highly effective solid-state photochromism from neutral SP molecules initially nonphotochromic in the crystalline state. The photoresponses of the SP?POT systems in the solid state strongly depend on the nature and the number of grafted SP groups.
    Mots-clés : E-POM, POLE 2, POM.


  • C. Rinfray, G. Izzet, J. Pinson, S. Gam Derouich, J. - J. Ganem, C. Combellas, F. Kanoufi, et A. Proust, « Electrografting of Diazonium-Functionalized Polyoxometalates: Synthesis, Immobilisation and Electron-Transfer Characterisation from Glassy Carbon », Chemistry – A European Journal, vol. 19, nᵒ 41, p. 13838–13846, 2013.
    Résumé : Polyoxometalates (POMs) are attractive candidates for the rational design of multi-level charge-storage materials because they display reversible multi-step reduction processes in a narrow range of potentials. The functionalization of POMs allows for their integration in hybrid complementary metal oxide semiconductor (CMOS)/molecular devices, provided that fine control of their immobilisation on various substrates can be achieved. Owing to the wide applicability of the diazonium route to surface modification, a functionalized Keggin-type POM [PW11O39Ge(p-C6H4-CC-C6H4-$\rm N+\hfill \atop 2\hfill$)]3− bearing a pending diazonium group was prepared and subsequently covalently anchored onto a glassy carbon electrode. Electron transfer with the immobilised POM was thoroughly investigated and compared to that of the free POM in solution.
    Mots-clés : diazonium grafting, E-POM, Electron transfer, electron transport, POLE 2, Polyoxometalates, POM, surface immobilization.


  • C. Schäffer, A. M. Todea, H. Bögge, S. Floquet, E. Cadot, V. S. Korenev, V. P. Fedin, P. Gouzerh, et A. Müller, « A further step towards tuning the properties of metal-chalcogenide nanocapsules by replacing skeletal oxide by sulphide ligands », Dalton Transactions, vol. 42, nᵒ 2, p. 330-333, 2013.
    Résumé : Addition of [Mo2VO2(μ-O)(μ-S)(aq)]2+ linker-type units to a solution/dynamic library containing tungstates results via the formation of the complementary pentagonal {(W)W5} units logically in the self-assembly of a mixed oxide/sulphide {WVI72MoV60}-type Keplerate, thereby demonstrating the ability to tune th
    Mots-clés : building-blocks, capsule, centers, chemistry, clusters, dynamic library, E-POM, keplerate-type, molybdenum-oxide, POLE 2, POM, pores, x-ray structures.


  • R. Villanneau, A. B. Djamâa, L. - M. Chamoreau, G. Gontard, et A. Proust, « Bisorganophosphonyl and -Organoarsenyl Derivatives of Heteropolytungstates as Hard Ligands for Early-Transition-Metal and Lanthanide Cations », European Journal of Inorganic Chemistry, vol. 2013, nᵒ 10-11, p. 1815–1820, 2013.
    Résumé : The coordination properties of bisorganophosphonyl and bisorganoarsenyl derivatives of heteropolytungstates towards lanthanides and early-transition-metal cations were studied in organic medium. This new class of vacant polyoxometalate (POM) hybrids proved to conserve coordination sites after the grafting of the RP=O2+ or RAs=O2+ groups onto the trivacant A,α-[PW9O34]9– and B,α-[AsW9O33]9– platforms. The consequence of the presence of free P=O or As=O groups is an increase of the hardness of the coordination sites in these anions (according to Pearson's HSAB theory). Although soft divalent transition metal cations were hardly coordinated with these hybrid monovacant POMs, complexes with hard s group (Ca2+), lanthanide (La3+, Ce3+) and d0 early-transition-metal cations were obtained and studied, in particular by single crystal X-ray diffraction. Owing to the possibility of modification of the trivacant platform, the type of the grafted function (phosphonyl or arsenyl) or the organic function R, these systems offer a unique possibility to finely modulate the coordination sphere of the cation.
    Mots-clés : Calcium, Coordination chemistry, E-POM, lanthanides, organic–inorganic hybrids, POLE 2, Polyoxometalates, POM, Titanium, transition metals, Tungsten, Vanadium.


  • R. Villanneau, A. Marzouk, Y. Wang, A. B. Djamaa, G. Laugel, A. Proust, et F. Launay, « Covalent Grafting of Organic–Inorganic Polyoxometalates Hybrids onto Mesoporous SBA-15: A Key Step for New Anchored Homogeneous Catalysts », Inorganic Chemistry, vol. 52, nᵒ 6, p. 2958-2965, mars 2013.
    Résumé : Covalent grafting of heteropolyanions hybrids B,α-[AsIIIW9O33{P(O)(CH2CH2CO2H)}2]5- on 3-aminopropyl functionalized SBA-15 has been achieved through the formation of peptide bonds. The covalent link has been confirmed by using IR and 13C CP MAS NMR spectroscopies. Electrostatic interactions between carboxylate and protonated amines have been discarded on the basis of the retention of POMs after repeated washings of the resulting material by ionic liquid (bmimCl). This is the first example of anchored monovacant polyoxometalates (POM) in which nucleophilic oxygen atoms are still available after incorporation into mesoporous supports. Further characterization of the textural properties of grafted materials has shown that they still retain an important mesoporosity, which is compatible with their potential use in heterogeneous catalysis. Such systems are thus interesting candidates for the preparation of anchored homogeneous catalysts in which the POMs would play the role of polydentate inorganic ligands for the active centers.
    Mots-clés : E-POM, POLE 2, POM.

2012


  • S. Blanchard, E. Derat, M. Desage-El Murr, L. Fensterbank, M. Malacria, et V. Mouries-Mansuy, « Non-Innocent Ligands: New Opportunities in Iron Catalysis », European Journal of Inorganic Chemistry, nᵒ 3, p. 376-389, janv. 2012.
    Résumé : Introduced in the late sixties, non-innocent (or redox) ligands have been extensively studied for their unusual and intriguing chemical behavior. Their ability to delocalize and/or provide electrons to the metal center of organometallic complexes confers them undisputable chemical interest and has proved valuable in the development of novel synthetic methodologies. This review will focus on the chemistry and applications of low-valent iron complexes bearing potentially non-innocent ligands. Because of the elusive nature of these ligands, and whenever possible, theoretical calculations and analysis of spectroscopic data will be presented in an effort to provide insights into the catalytic activity of the complexes.
    Mots-clés : 2-pi+2-pi cycloaddition, 2-state reactivity, ab-initio, COS, cross-coupling reactions, Density functional calculations, E-POM, electronic-structure, ethylene polymerization catalysts, h bond activation, Iron, Low-valent iron complexes, MACO, mechanistic aspects, Non-innocent ligands (NILs), olefin polymerization, POLE 1, POLE 2, POM, Redox chemistry, transition-metal complexes.

  • S. Brossard, F. Volatron, L. Lisnard, M. - A. Arrio, L. Catala, C. Mathoniere, T. Mallah, C. C. dit Moulin, A. Rogalev, A. Smekhova, et P. Sainctavit, « Investigation of the Photoinduced Magnetization of Copper Octacyanomolybdates Nanoparticles by X-ray Magnetic Circular Dichroism », Journal of the American Chemical Society, vol. 134, nᵒ 1, p. 222-228, janv. 2012.
    Résumé : Through an extensive set of SQUID magnetic measurements, X-ray absorption spectroscopy, and X-ray magnetic circular dichroism, we have determined the nature of the metastable photomagnetic phase in the cyano-bridged 3D network Cs2Cu7[Mo(CN)(8)](4). The photomagnetic effect is induced by the photoconversion of Mo(IV) ions in low spin (LS) configuration (S = 0) into Mo(IV) ions in high spin (HS) configuration (S = 1). The magnetic and spectroscopic measurements fully support the
    Mots-clés : E-POM, ERMMES, MMMAX, POLE 2.

  • L. de Viguerie, A. Mouret, H. - P. Brau, V. Nardello-Rataj, A. Proust, et P. Bauduin, « Surface pressure induced 2D-crystallization of POM-based surfactants: preparation of nanostructured thin films », Crystengcomm, vol. 14, nᵒ 24, p. 8446-8453, 2012.
    Résumé : The present study investigates the deposition of hybrid organic/inorganic monolayers composed of polyoxometalate (POM) of the Keggin-type [PW12O40](3-) electrostatically linked to three alkylammonium surfactants. The surface pressure dependence, i.e. Langmuir isotherm, as well as their 2D self-assembly has been investigated with mono-and double-chained surfactants and by varying the alkyl chain length. Stable monolayers were obtained for the hexadecyltrimethylammonium and the didodecyldimethylammonium POM surfactants, called respectively C16POM and 2C12POM. It was found that increasing the surface pressure led to the formation of crystallized nano-and micro-domains in coexistence with the monolayer. The crystallites formed were monodisperse in their size repartition and showed various shapes and sizes: oblate nanoparticles of nanometric size (height ca. 7 nm, diameter ca. 140 nm) for C16POM and micrometric 2D-hexagonal crystallites for 2C12POM. The monolayers and the micro-(nano-) crystallites have been characterized after transfer on silicon wafers by means of atomic force microscopy (AFM), transmission electron microscopy (TEM) and surface-enhanced ellipsometric contrast (SEEC). High crystallinity of the hexagonal aggregates was revealed by electron diffraction (ED). For 2C12POM the monolayer formed before crystallisation is in a 2D-liquid state with the alkyl chains pointing out of the water with an average angle of the alkyl chains to the normal of the plane estimated at 50 degrees. It is shown that the surface pressure induced crystallization of the POM surfactant results in the change of the ammonium surfactant arrangement around the POM with the alkyl chains pointing up and down the POM units showing a reverse bilayer-like structure. This change in the ammonium surfactant arrangement in response to the increase of the surface pressure enables (i) to reduce the molecular area and (ii) the formation of a 2D-hexagonal crystalline lattice of POM units. On the other hand for C16POM the formation of oblate nanoparticles is driven by a three-dimensional growth at the water surface.
    Mots-clés : E-POM, POLE 2, POM.

  • L. Dermeche, N. Salhi, S. Hocine, R. Thouvenot, et C. Rabia, « Effective Dawson type polyoxometallate catalysts for methanol oxidation », Journal of Molecular Catalysis a-Chemical, vol. 356, p. 29-35, avr. 2012.
    Résumé : Dawson type polyoxometallates K6P2MoxW18-xO62 (x=0, 5, 6) and alpha 1 and alpha 2-K7P2Mo5VW12O62 were prepared and characterized by BET, IR. UV-vis and P-31 NMR spectroscopies and thermal analysis (TG and DTA) and tested in methanol oxidation at 260 degrees C in the presence of molecular oxygen. The Dawson compounds were found to be active in this reaction and the product distribution (formaldehyde, methyl formate, dimethylether, dimethoxymethane) depends on the polyanion composition and on the framework symmetry. alpha-K6P2W18O62 exhibits an excellent catalytic performance with ca. 27% of methanol conversion and 98% of dimethylether selectivity. alpha 1-K7P2Mo5VW12O62 and alpha 2-K7P2Mo5VW12O62 show a similar activity (17-19% of conversion) with 49% of methyl formate selectivity and 41% of formaldehyde selectivity respectively. alpha-K6P2Mo6W12O62 is the most oxidizing catalyst and the most selective toward the methyl formate (ca. 53%). (C) 2011 Elsevier B.V. All rights reserved.
    Mots-clés : acid, Dawson anions, dimethoxymethane, Dimethyl ether, E-POM, Formaldehyde, heteropolyanions, isobutane, keggin phosphomolybdate salts, Methanol oxidation, Methyl formate, oxide catalysts, performance, POLE 2, POM, selective oxidation, silica, tert-butyl ether.


  • J. Fortage, C. Peltier, C. Perruchot, Y. Takemoto, Y. Teki, F. Bedioui, V. Marvaud, G. Dupeyre, L. Pospísil, C. Adamo, M. Hromadová, I. Ciofini, et P. P. Lainé, « Single-Step versus Stepwise Two-Electron Reduction of Polyarylpyridiniums: Insights from the Steric Switching of Redox Potential Compression », Journal of the American Chemical Society, vol. 134, nᵒ 5, p. 2691-2705, 2012.
    Résumé : Contrary to 4,4?-dipyridinium (i.e., archetypal methyl viologen), which is reduced by two single-electron transfers (stepwise reduction), the 4,1?-dipyridinium isomer (so-called ?head-to-tail? isomer) undergoes two electron transfers at apparently the same potential (single-step reduction). A combined theoretical and experimental study has been undertaken to establish that the latter electrochemical behavior, also observed for other polyarylpyridinium electrophores, is due to potential compression originating in a large structural rearrangement. Three series of branched expanded pyridiniums (EPs) were prepared: N-aryl-2,4,6-triphenylpyridiniums (Ar-TP), N-aryl-2,3,4,5,6-pentaphenylpyridiniums (Ar-XP), and N-aryl-3,5-dimethyl-2,4,6-triphenylpyridinium (Ar-DMTP). The intramolecular steric strain was tuned via N-pyridinio aryl group (Ar) phenyl (Ph), 4-pyridyl (Py), and 4-pyridylium (qPy) and their bulky 3,5-dimethyl counterparts, xylyl (Xy), lutidyl (Lu), and lutidylium (qLu), respectively. Ferrocenyl subunits as internal redox references were covalently appended to representative electrophores in order to count the electrons involved in EP-centered reduction processes. Depending on the steric constraint around the N-pyridinio site, the two-electron reduction is single-step (Ar = Ph, Py, qPy) or stepwise (Ar = Xy, Lu, qLu). This steric switching of the potential compression is accurately accounted for by ab initio modeling (Density Functional Theory, DFT) that proposes a mechanism for pyramidalization of the Npyridinio atom coupled with reduction. When the hybridization change of this atom is hindered (Ar = Xy, Lu, qLu), the first reduction is a one-electron process. Theory also reveals that the single-step two-electron reduction involves couples of redox isomers (electromers) displaying both the axial geometry of native EPs and the pyramidalized geometry of doubly reduced EPs. This picture is confirmed by a combined UV?vis?NIR spectroelectrochemical and time-dependent DFT study: comparison of in situ spectroelectrochemical data with the calculated electronic transitions makes it possible to both evidence the distortion and identify the predicted electromers, which play decisive roles in the electron-transfer mechanism. Last, this mechanism is further supported by in-depth analysis of the electronic structures of electrophores in their various reduction states (including electromeric forms).
    Mots-clés : E-POM, POLE 2, SUPRA.


  • G. Izzet, M. Ménand, B. Matt, S. Renaudineau, L. - M. Chamoreau, M. Sollogoub, et A. Proust, « Cyclodextrin-Induced Auto-Healing of Hybrid Polyoxometalates », Angewandte Chemie International Edition, vol. 51, nᵒ 2, p. 487–490, 2012.
    Mots-clés : auto-healing, cyclodextrins, E-POM, GOBS, Host–guest systems, POLE 2, POLE 3, Polyoxometalates, POM.

  • D. Laurencin, R. Thouvenot, K. Boubekeur, P. Gouzerh, et A. Proust, « Connecting ruthenium substituted Keggin-type tungstophosphates by oxotungstic bridges: Evidence for the steric effect of {RuL3}(2+) (L-3 = eta(6)-arene, (DM(S)under-barO)(3)) fragments », Comptes Rendus Chimie, vol. 15, nᵒ 2-3, p. 135-142, mars 2012.
    Résumé : The intrinsic reactivity of the organoruthenium-grafted tungstophosphates [alpha-PW11O39(Ru(eta(6)-arene)(H2O))](5-) and [alpha-PW11O39(Ru(DM (S) under barO)(3)(H2O)}(15-) has been studied as a prerequisite for later catalytic studies. Upon reflux in aqueous solution, they partially transform into [{PW11O39Ru(eta(6)-arene)}(2){WO2}](8-) (when arene = benzene, toluene ...) and [alpha-PW11O39{Ru(DM (S) under barO)}(15)-, respectively. In the former case, the conversion is markedly increased by deliberate addition of tungstate: through a solution NMR study, we show that [(PW11O39Ru(eta(6)-p-cymene))(2)(WO2)(18-) is quantitatively obtained by refluxing a 2:1:2 mixture of [alpha-PW11O39](7-). [Ru(eta(6)-p-cymene)Cl-2](2) and [WO2](2-) at pH 3. In contrast, a different type of complex, [(PW11O39Ru(DM (S) under barO)(3)}(2){(WO2(H2O))(2)O)](8-), is formed by reaction of [alpha-PW11O39{Ru(DM (S) under barO)(3)(H2O)}](5-) with tungstate; it has been characterized by single crystal X-ray diffraction analysis of an acidic potassium salt, and by W-183 solution NMR. The more sterically demanding {Ru(DM (S) under barO)(3)}(2+) fragment probably does not allow the formation of [{PW11O39Ru(DM (S) under barO)(3)}(2){WO2}](8-), while connection of (PW11O39Ru(DMSO)(3)}(5-) subunits is possible through the larger {(WO2(H2O))(2)O}(2+) bridge. (C) 2011 Academic des sciences. Published by Elsevier Masson SAS. All rights reserved.
    Mots-clés : catalyzed reactions, crystal-structure, E-POM, framework fluxionality, lacunary polyoxometalate, metal-oxide analogs, molecular-structure, Organometallic oxides, organometallic ruthenium(ii), POLE 2, Polyoxometalates, POM, Ruthenium, structural-characterization, trisubstituted heteropolytungstates, Tungsten, x-ray.


  • L. Leclercq, A. Mouret, A. Proust, V. Schmitt, P. Bauduin, J. - M. Aubry, et V. Nardello-Rataj, « Pickering Emulsion Stabilized by Catalytic Polyoxometalate Nanoparticles: A New Effective Medium for Oxidation Reactions », Chemistry – A European Journal, vol. 18, nᵒ 45, p. 14352–14358, 2012.
    Résumé : Decyl-, dodecyl-, and tetradecyltrimethylammonium cations were combined with the catalytic polyoxometalate [PW12O40]3− anion to give spherical and monodisperse nanoparticles that are able to stabilize emulsions in the presence of water and an aromatic solvent. This triphasic liquid/solid/liquid system, based on a catalytic surfactant, is particularly efficient as a reaction medium for epoxidation reactions that involve hydrogen peroxide. The reactions proceed at competitive rates with straightforward separation of the phases by centrifugation. Such catalytic “Pickering” emulsions combine the advantages of heterogeneous catalysis and biphasic catalysis without the drawbacks (e.g., catalyst leaching or separation time).
    Mots-clés : E-POM, epoxidation, nanoparticles, oxidation, Pickering emulsions, POLE 2, Polyoxometalates, POM.

  • J. Martinez-Lillo, L. - M. Chamoreau, A. Proust, M. Verdaguer, et P. Gouzerh, « Hexanuclear manganese(III) single-molecule magnets from derivatized salicylamidoximes », Comptes Rendus Chimie, vol. 15, nᵒ 10, p. 889-894, oct. 2012.
    Résumé : Four novel hexanuclear manganese(III) complexes based on derivatized salicylamidoximes, [Mn-6(III)(mu(3)-O)(2)(O2CPh)(2)(Me2N-sao)(6)(EtOH)(4)] (1), [Mn-6(III)(mu(3)-O)(2)(O2CPh)(2)(Me2N-sao)(6)((PrOH)-Pr-i)(4)] (2), [Mn-6(III)(mu(3)-O)(2)(O2CPh)(2)(Et2N-sao)(6)(EtOH)(4)] (3) and [Mn-6(III)(mu(3)-O)(2)(O2CPh)(2)(Et2N-Sao)(6)((PrOH)-Pr-i)(4)] (4) (Me2N-Hsao = dimethylsalicylamidoxime; Et2N-Hsao = diethylsalicylamidoxime), have been prepared and characterized. Single-crystal X-ray diffraction allows one to determine that 1.2CHCl(3) and 4 crystallize in the triclinic system with space group P(-1), whereas 3 crystallizes in the monoclinic system with space group P2(1)/n. dc and ac magnetic susceptibility measurements of 1-4 reveal ferromagnetic coupling between Mn(III) metal ions and single-molecule magnet behaviour. The anisotropy barriers are 56, 52, 71 and 59 K for 1, 2, 3 and 4, respectively. (C) 2012 Academie des sciences. Published by Elsevier Masson SAS. All rights reserved.
    Mots-clés : anisotropy, chemistry, Crystal structures, E-POM, family, Magnetic properties, Manganese(III) complexes, metal-complexes, oximes, POLE 2, POM, reactivity, Salicylamidoximes, single-molecule magnets.


  • J. Martínez-Lillo, A. - R. Tomsa, Y. Li, L. - M. Chamoreau, E. Cremades, E. Ruiz, A. - L. Barra, A. Proust, M. Verdaguer, et P. Gouzerh, « Synthesis, crystal structure and magnetism of new salicylamidoxime-based hexanuclear manganese(iii) single-molecule magnets », Dalton Transactions, vol. 41, nᵒ 44, p. 13668, 2012.


  • B. Matt, J. Moussa, L. - M. Chamoreau, C. Afonso, A. Proust, H. Amouri, et G. Izzet, « Elegant Approach to the Synthesis of a Unique Heteroleptic Cyclometalated Iridium(III)-Polyoxometalate Conjugate », Organometallics, vol. 31, nᵒ 1, p. 35-38, janv. 2012.
    Résumé : A novel heteroleptic cyclometalated iridium(III) complex with one picolinic acid derivative bearing a pendant terminal alkynyl tether has been prepared following a new synthetic route. This pendant alkynyl tether can be further engaged in palladium C?C coupling reactions, allowing its grafting to a Keggin-type polyoxometalate and thus providing a unique iridio-POM conjugate.
    Mots-clés : ARC, E-POM, POLE 1, POLE 2, POM.


  • D. Mercier, S. Boujday, C. Annabi, R. Villanneau, C. - M. Pradier, et A. Proust, « Bifunctional Polyoxometalates for Planar Gold Surface Nanostructuration and Protein Immobilization », The Journal of Physical Chemistry C, vol. 116, nᵒ 24, p. 13217-13224, 2012.
    Résumé : Surface nanostructuration was successfully achieved by binding the polyoxometalate (POM) (NBu4)3[PW11O39{(SiC6H4NH2)2O}] covalently onto planar gold surfaces. To do so, POMs functionalized with two terminal amino groups were synthesized and reacted with a mercaptoundecanoic acid self-assembled monolayer adsorbed on gold. These amine-terminated POM macroanions proved to be remarkably efficient as nanostructuring agents. Using polarization-modulated infrared reflection absorption spectroscopy (PM-IRRAS), photoelectron spectroscopy (XPS), and atomic force microscopy (AFM), conditions were optimized to elaborate a dense and well-dispersed layer of POMs, leaving a ?free? amine function for the further linkage of proteins. Antirabbit immunoglobulins (anti-rIgGs) were thus grafted on the POM-structured layer, and the recognition of their specific target, rabbit immunoglobulin (rIgGs), was tested by using a quartz crystal microbalance with dissipation measurement (Q

    CM-D). The recognition was good and highly specific, indicating that an efficient, nanostructured biosensor has been constructed. The method reported herein can be easily applied, not requiring any sophisticated experimental setup, and is promising for the patterning of any molecular probes bearing amine groups.
    Mots-clés : E-POM, POLE 2, POM.


  • A. Müller et P. Gouzerh, « From linking of metal-oxide building blocks in a dynamic library to giant clusters with unique properties and towards adaptive chemistry », Chemical Society Reviews, vol. 41, nᵒ 22, p. 7431-7463, oct. 2012.
    Résumé : Following Nature's lessons, today chemists can cross the boundary of the small molecule world to construct multifunctional and highly complex molecular nano-objects up to protein size and even cell-like nanosystems showing responsive sensing. Impressive examples emerge from studies of the solutions of some o Polyoxometalate cluster science
    Mots-clés : E-POM, POLE 2, POM.


  • E. Pardo, C. Train, H. Liu, L. - M. Chamoreau, B. Dkhil, K. Boubekeur, F. Lloret, K. Nakatani, H. Tokoro, S. -ichi Ohkoshi, et M. Verdaguer, « Multiferroics by Rational Design: Implementing Ferroelectricity in Molecule-Based Magnets », Angewandte Chemie International Edition, vol. 51, nᵒ 33, p. 8356–8360, 2012.
    Mots-clés : Chromium, E-POM, Manganese, Molecular magnets, multiferroics, POLE 2, POM.

  • A. Proust, B. Matt, R. Villanneau, G. Guillemot, P. Gouzerh, et G. Izzet, « Functionalization and post-functionalization: a step towards polyoxometalate-based materials », Chemical Society Reviews, vol. 41, nᵒ 22, p. 7605-7622, 2012.
    Résumé : Polyoxometalates (POMs) have remarkable properties and a great deal of potential to meet contemporary societal demands regarding health, environment, energy and information technologies. However, implementation of POMs in various functional architectures, devices or materials requires a processing step. Most developments have considered the exchange of POM counterions in an electrostatically driven approach: immobilization of POMs on electrodes and other surfaces including oxides, embedding in polymers, incorporation into Layer-by-Layer assemblies or Langmuir-Blodgett films and hierarchical self-assembly of surfactant-encapsulated POMs have thus been thoroughly investigated. Meanwhile, the field of organic-inorganic POM hybrids has expanded and offers the opportunity to explore the covalent approach for the organization or immobilization of POMs. In this critical review, we focus on the use of POM hybrids in selected fields of applications such as catalysis, energy conversion and molecular nanosciences and we endeavor to discuss the impact of the covalent approach compared to the electrostatic one. The synthesis of organic-inorganic POM hybrids starting from bare POMs, that is the direct functionalization of POMs, is well documented and reliable and efficient synthetic procedures are available. However, as the complexity of the targeted functional system increases a multi-step strategy relying on the post-functionalization of preformed hybrid POM platforms could prove more appealing. In the second part of this review, we thus survey the synthetic methodologies of post-functionalization of POMs and critically discuss the opportunities it offers compared to direct functionalization.
    Mots-clés : charge-transfer, cyclopentadienyltitanium heteropolytungstate anions, dawson-type polyoxotungstates, E-POM, individually distinguishable labels, keggin-type polyoxometalate, langmuir-blodgett technique, nonlinear-optical properties, POLE 2, POM, scanning-tunneling-microscopy, single-molecule magnets, transmission electron-microscopy.


  • L. Ruhlmann, D. Schaming, I. Ahmed, A. Courville, J. Canny, et R. Thouvenot, « Spectroscopic and Electrochemical Study of the Interconversion and Decomplexation of Cobalt(II) Sandwich Polyoxometalates Based on a Dawson-Type Anion », Inorganic Chemistry, vol. 51, nᵒ 15, p. 8202-8211, 2012.
    Résumé : The reaction of the trivacant Dawson polyoxometalate α-[P2W15O56]12? and the divalent cations Co2+ is known to form a symmetrically derived sandwich complex of formula ??-[Co4(H2O)2(P2W15O56)2]16? [symbolized as ??-Co4(P2W15)2] at low pH (ca. pH 3). We have shown previously that, by a slight modification of the reaction conditions, trinuclear α?-[(NaOH2)Co3(H2O)(P2W15O56)2]17? and dinuclear [(NaOH2)2Co2(P2W15O56)2]18? complexes [symbolized as α?-NaCo3(P2W15)2 and Na2Co2(P2W15)2, respectively] can be synthesized as aqueous-soluble sodium salts. α?-NaCo3(P2W15)2 is a ?lacunary? sandwich complex that can add a Co2+ cation to form nearly quantitatively an unsymmetrical Dawson tetracobalt sandwich polyoxometalate, α?-[Co4(H2O)2(P2W15O56)2]16? [symbolized as α?-Co4(P2W15)2]. Thus, for Co4(P2W15)2, the junctions between the trivacant {P2W15} subunits and the central tetrameric unit can be either both ? type or ? and α types. The interconversion between α?-Co4(P2W15)2 and ??-Co4(P2W15)2 and the decomplexation process at low pH, leading to the formation of α?-NaCo3(P2W15)2 and/or Na2Co2(P2W15)2, have been followed in aqueous solution at various pH values by electrochemistry, UV?visible absorption spectroscopy, and 31P NMR spectroscopy.
    Mots-clés : E-POM, POLE 2, POM.

  • C. Schaeffer, A. M. Todea, P. Gouzerh, et A. Mueller, « Spontaneous self-assembly of a giant spherical metal-oxide Keplerate: addition of one building block induces "immediate'' formation of the complementary one from a constitutional dynamic library », Chemical Communications, vol. 48, nᵒ 3, p. 350-352, 2012.
    Résumé : The addition of dinuclear {Mo(2)} units to a dynamic library containing molybdates results in the spontaneous self-assembly of a giant spherical metal-oxide species of the type {(Mo)-Mo(5)}(12){Mo(2)}(30) while the required pentagonal {(Mo)Mo(5)} building blocks are "immediately'' formed.
    Mots-clés : bond, capsules, clusters, complexes, E-POM, Molybdenum, POLE 2, polyoxomolybdate, POM, raman intensities, spectra, supramolecular chemistry, topology.


  • A. M. Todea, A. J. M. Al-Karawi, T. Glaser, S. Walleck, L. - M. Chamoreau, R. Thouvenot, P. Gouzerh, et A. Müller, « Encapsulation of Keggin-type anions in reduced molybdenum–iron-type Keplerates as a general phenomenon », Inorganica Chimica Acta, vol. 389, p. 107-111, 2012.
    Résumé : Upon standing in air at room temperature, acidified aqueous solutions (pH 2) obtained by dissolving sodium molybdate, iron(II) chloride, acetic acid and potassium dodecatungstoborate led to the formation of greenish thin plate crystals (1) containing discrete clusters. Upon drying 1 at room temperature crosslinking of the clusters occurs in a solid-state reaction which leads to compound 2. Based on crystallographic studies of 1 and on extensive physical characterization (vibrational, NMR, Mössbauer spectra and magnetic susceptibility measurements) of 2, it was shown that compounds 1 and 2 contain reduced spherical {Mo72Fe30} Keplerate-type shells encapsulating non-reduced tungstoborate Keggin-type anions. The properties and structures of these compounds are compared to related hybrid structures containing in principle easier reducible molybdophosphate or molybdosilicate cores. According to the results the present type of encapsulation can be considered as a general phenomenon.
    Mots-clés : Core–shell clusters, E-POM, host–guest chemistry, Keggin ions, Keplerate, POLE 2, POM.
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