Bruno Alonso

Institut Charles Gerhardt, Montpelhièr, Languedoc-Roussillon, France

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Publications (95)340.3 Total impact

  • Eddy Dib · Tzonka Mineva · Bruno Alonso
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    ABSTRACT: This chapter is devoted to the recent advances in 14N solid-state NMR related to both theoretical and practical aspects. First, the last NMR methods developed to facilitate the direct or indirect detection of 14N signals are presented in a succinct and comprehensive way. Further, the theoretical approaches that have been applied to model the 14N NMR quadrupolar parameters are explained and discussed regarding their ability to yield pertinent information on structures and dynamics of nitrogen containing solids. Last, most of the results obtained by 14N NMR characterization on inorganic, hybrid organic–inorganic, organic, or biological materials are presented, and the related NMR parameters are compiled in tables.
    No preview · Article · Sep 2015 · Annual Reports on NMR Spectroscopy
  • Eddy Dib · Antoine Gimenez · Tzonka Mineva · Bruno Alonso
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    ABSTRACT: The local structure of as-synthesised silicalite-1 zeolites is modified using asymmetric R(Pr)3N+ structure directing agents. Using multi-nuclear NMR (1H, 13C, 14N, 19F, 29Si), we show for the first time the ability of these cations to adopt preferential orientations at the zeolite channels’ crossing.
    No preview · Article · Aug 2015 · Dalton Transactions
  • Dib Eddy · Tzonka Mineva · Philippe Gaveau · Bruno Alonso
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    ABSTRACT: We have investigated using 14N NMR different types of materials containing tetrapropylammonium cations. We consider the tetrapropylammonium bromide crystal as well as two different microporous materials silicalite-1 and AlPO-5, with MFI and AFI topology respectively, where the tetrapropylammonium cation plays the role of structure directing agent. 14N NMR quadrupolar coupling parameters were determined experimentally for all the crystals. In addition calculations based on Density Functional Theory with empirical dispersion (DFT-D) were performed on the MFI type zeolite. The sensitivity of the 14N quadrupolar coupling parameters to the spatial distribution of the anions in the zeolite’s framework is emphasized.
    No preview · Article · Jul 2015 · The European Physical Journal Special Topics
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    ABSTRACT: A simple and green synthesis route was disclosed for the achievement of mesoporous alumina microparticles employing polysaccharide nanoparticles (α-chitin nanorods) as templates. Pore textures can be tuned by the cationic alumina precursor. Compared to small cations, the use of Al13 and Al30 oxo-hydroxo clusters leads to better defined and elongated mesopores. Electron microscopy and spectroscopic ((13) C, (27) Al NMR, XPS) measurements demonstrated that this is related to the effective coating of α-chitin nanorods by these pre-condensed colloids. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.
    Full-text · Article · Jan 2015 · Chemistry - A European Journal
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    ABSTRACT: Silica-titania materials with improved catalytic performances were elaborated as mesoporous microparticles by combining sol-gel and spray-drying processes with the self-assembly properties of α-chitin nanorods acting as bio-templates. Three different synthesis’ approaches are discussed, leading to materials with varied textural and chemical characteristics studied by SEM, N2 volumetry, TEM, XPS and DR-UV techniques. The use of water or ethanol as initial solvent for the chitin nanorods’ suspensions, as well as the mixing conditions of the precursors show to have a significant impact on the final properties. Materials of specific surface areas of up to 590 m2.g-1 and porous volumes of up to 0.84 mL.g-1, with low surface Si/Ti ratio could be disclosed. Properties were further investigated by employing the silica-titania materials as heterogeneous catalysts for the sulfoxidation of bulky model compounds. The location of Ti active sites at the pore surface has been maximized and allows for improved productivity.
    Full-text · Article · Aug 2014 · Catalysis Science & Technology
  • Eddy Dib · Bruno Alonso · Tzonka Mineva
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    ABSTRACT: The Density Functional Theory based method with periodic boundary conditions and addition of a pair wised empirical correction for the London dispersion energy (DFT-D) was used to study the NMR quadrupolar interaction (coupling constant CQ and asymmetry parameter ηQ) of 14N nuclei in a homologous series of tetra-n-alkylammonium halides (CxH2x+1)4N+X- (x =1 - 4), (X = Br, I). These 14N quadrupolar properties are particularly challenging for the DFT-D computations because of their very high sensitivity to tiny geometrical changes, being negligible for other spectral property calculations as for example NMR 14N chemical shift. In addition, the polarization effect of the halide anions in the considered crystal mesophases combines with interactions of van der Waals type between cations and anions. Comparing experimental and theoretical results, the performance of PBE-D functional is preferred than that of B3LYP-D. The results demonstrated a good transferability of the empirical parameters in the London dispersion formula for crystals with two or more carbons per alkyl group in the cations, whereas the empirical corrections in the tetramethylammonium halides appeared inappropriate for the quadrupolar interaction calculation. This is attributed to the enhanced cation-anion attraction, which causes a strong polarization at the nitrogen site. Our results demonstrated that the 14N CQ and ηQ are predominantly affected by the molecular structures of the cations, adapted to the symmetry of the anion arrangements. The long-range polarization effect of the surrounding anions at the target nitrogen site becomes more important for cells with lower spatial symmetry.
    No preview · Article · Apr 2014 · The Journal of Physical Chemistry A
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    ABSTRACT: Two model drugs of different physico-chemical and pharmaceutical properties (ibuprofen, acetaminophen) have been incorporated together or separately in silica-based microspheres using sol–gel and spray-drying processes. A variable amount of a neutral surfactant Brij-56© has also been added. The properties of the microspheres vary significantly depending on their composition. Three kinds of texture are identified: (1) silica containing spheroid nano-domains (formed by ibuprofen; diameters between 20 and 100 nm), (2) silica containing worm-like mesophases (formed by Brij-56© and both model drugs, typical correlation distances ~6 nm), (3) silica intimately mixed with the drug (acetaminophen) without visible phase-separation. The kinetics of drug release in simulated intestinal fluid strongly depend on these textures. The association of ibuprofen and acetaminophen in a single type of microsphere and without surfactant favours a concomitant release. Possible mechanisms of materials’ formation are discussed.
    No preview · Article · Nov 2013 · Journal of Sol-Gel Science and Technology
  • Eddy Dib · Tzonka Mineva · Philippe Gaveau · Bruno Alonso

    No preview · Conference Paper · Oct 2013
  • Eddy Dib · Tzonka Mineva · Philippe Gaveau · Bruno Alonso
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    ABSTRACT: Local order in as-synthesised zeolites templated by tetraalkylammonium cations is proven from solid-state (14)N NMR and related quadrupolar parameters, opening new perspectives in the study of porous materials.
    No preview · Article · Jul 2013 · Physical Chemistry Chemical Physics
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    ABSTRACT: Uniaxially anisotropic chitin-silica nanocomposite solids have been obtained thanks to the electric field-induced macroscopic alignment of liquid-crystalline reactive co-suspensions. We demonstrate how chitin nanorods (260 nm long, 23 nm thick) can be aligned upon the application of an a.c. electric field, and within water-ethanol suspensions containing reactive siloxane oligomers (Dh ~ 3 nm). The alignment at the millimeter length scale is monitored by in situ SAXS and polarized light optical microscopy. The composition and state (isotropic, chiral nematic) of the co-suspensions are proven to be determining factors. For nematic phases, the alignment is preserved when the electric field is switched off. Further solvent evaporation induces sol-gel transition, and uniaxially anisotropic chitin-silica nanocomposites are formed after complete drying of the aligned nematic suspensions. Here, the collective response of colloidal mesophases to external electric fields and the subsequent formation of ordered nanocomposite solids would represent a new opportunity for materials design.
    No preview · Article · Jun 2013 · Langmuir
  • Eddy Dib · Bruno Alonso · Tzonka Mineva · Philippe Gaveau

    No preview · Conference Paper · May 2013
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    Bruno Alonso · Claire Marichal
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    ABSTRACT: In this tutorial review we intend to give an overview of the potential of NMR spectroscopy, and in particular solid-state NMR, in characterising micelle-templated mesoporous materials. Different topics are covered including the study of formation mechanisms, the characterisation of structures, textures, surfaces and interfaces, functionalisation, dynamic properties and structure-reactivity correlations. Some selected examples illustrate the variety of information provided by this spectroscopy. Particular attention is paid to recent technological and/or methodological developments.
    Preview · Article · Nov 2012 · Chemical Society Reviews
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    ABSTRACT: The sorption properties towards dysprosium(III) ions of three samples of mesoporous silicas functionalized with phosphonic groups ≡ Si(CH2)2P(O)(OH)2 were studied. It was found that for the sample synthesized by spray-drying using OTAB as a template both sorption and desorption rate of Dy3+ ions is high, due to the defined porosity of the sorbent. Sorption of Dy3+ ions by bridged silsesquioxane xerogels with disordered structure is significantly hindered by diffusion processes, due to the chaotic packing of globules. Using a model for the chemical reactions, the composition of dysprosium(III) complexes with surface phosphonic groups were determined, and their formation constants were calculated. It was shown that xerogels with higher surface concentration of ligand groups (L), can form complexes DyL3 and DyL4 −. Meanwhile, the sample synthesized by spray-drying method forms only DyL2 + and DyL3 complexes. For this sample, complexes DyL3 are more stable than for xerogels. So, mesoporous silica derived by spray-drying method, with defined spatial porosity and relatively low surface concentration complexation groups, is characterized by the best sorption properties towards dysprosium(III) (adsorption and desorption kinetics, the value of the static sorption capacity).
    Full-text · Article · Oct 2012 · Journal of Porous Materials
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    ABSTRACT: Mesoporous silica–titania materials of tunable composition and texture, which present a high catalytic activity in the mild oxidation of sulfur compounds, have been obtained by combining the spray-drying process with the colloidal self-assembly of a-chitin nanorods (biopolymer acting as a template) and organo-metallic oligomers. The quest for synthetic routes leading to mesoporous silica materials bearing titania has been launched since the discovery that Ti containing zeolites such as TS-1 and b-Ti were efficient catalysts for the oxidation of a variety of organic compounds. 1 Due to their limited accessibility for large molecules, strategies for the design of mesoporous silica–titania materials have been developed, such as the direct synthesis of ordered mesoporous materials (e.g. Ti-MCM-41, Ti-MCM-48), 2 the grafting of Ti species onto meso-porous silicas 3 and both hydrolytic 4 and non-hydrolytic 5 sol–gel synthesis routes, which permitted to widen the application spectrum considerably. These materials show promising results for the mild oxidation of bulky molecules. 6 Yet, their synthesis relies on tedious procedures (use of a glove box, dry solvents, etc.), often requires expensive template materials such as CTAB, and in some cases low final Ti loadings are obtained. Bio-inspired templating techniques using biopolymers are valuable strategies that open up the way for alternative syntheses 7 and thus responding directly to the needs of Green Chemistry. 8 The ambition behind this is the transcription of the natural textural traits within the newly formed material. 9 A novel and general route for the formation of biopolymer– oxide nano-composites from sol–gel chemistry and colloidal self-assembly involving a-chitin nano-rods has recently been proposed. 10 The mesoporous silica obtained from these nano-composites showed a high modularity in the textural proper-ties. 11 Using chitin as a template provides the additional benefit of being purified from renewable resources, i.e. industrial wastes from shrimp fisheries. Recently, sol–gel chemistry has been combined with spray-drying processes to form new alumino-silicate catalysts. 12 Spray-drying is indeed an interesting process adapted to large-scale production in a continuous regime. Moreover, spray-drying allows the quenching of metastable states by fast solvent evaporation and solidification, whilst offering oppor-tunities to fine-tune the mesoporosity and chemical composi-tion of the resulting solid. 12,13 Herein, we describe for the first time the synthesis of mesoporous silica–titania materials using a-chitin-nanorods as a natural template, by exploiting the self-assembly proper-ties of these nanoparticles 14 associated with sol–gel chemis-try. 10,11 We demonstrate that textural properties (surface area, pore volume) of the synthesized materials can easily be tuned by varying the volume fraction of chitin particles added during the synthesis. Additionally, Si/Ti molar ratios can be adjusted. These materials have proven to be efficient catalysts for the oxidation of sulphur-containing compounds using hydrogen peroxide as a mild oxidation agent. The catalytic output of the performed reactions can perfectly be controlled by tuning the textural properties of the silica–titania material. The silica–titania catalysts are prepared by mixing first an ethanolic suspension of siloxane oligomers (B3 nm) with variable amounts of the titanium monomer precursor Ti(O i Pr) 2 (acac) 2 (Scheme 1).z The results presented here cor-respond to Si/Ti molar ratios from 19 to 70. An aqueous suspension of chitin nanorods (L = 260 AE 80 nm  D = 23 AE 3 nm) is subsequently introduced, and the resulting sol is exchanged with ethanol. Chitin-oxide microparticles are then formed by spray-drying the ethanolic solution with a variable chitin volume fraction, f CHI . And the final mesoporous samples are obtained by calcination. Dense particles with micrometer diameters (2.2 to 2.8 mm on average, see S2.3, ESIw) are obtained. Their surface roughness increases with the chitin content (Fig. 1a and c), in agreement with former results for chitin–silica nano-composites. 10 The electron-clear struc-tures observed in TEM reveal the presence of elongated pores Scheme 1 Synthesis of silica–titania nano-composites.
    Full-text · Article · Sep 2012 · Chemical Communications
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    ABSTRACT: Silica microspheres encapsulating ibuprofen in separated domains at the nanometre scale are formed by spray-drying and sol-gel processes. A detailed (1)H and (13)C NMR study of these microspheres shows that ibuprofen molecules are mobile and are interacting through hydrogen bonds with other ibuprofen molecules. (1)H magnetisation exchange NMR experiments were employed to characterize the size of the ibuprofen domains at the nanometre scale. These domains are solely formed by ibuprofen, and their diameters are estimated to be ∼40 nm in agreement with TEM observations. The nature and formation of these particular texture and drug dispersion are discussed.
    No preview · Article · Aug 2012 · Physical Chemistry Chemical Physics
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    ABSTRACT: Isotherms are measured for nitrogen, n-hexane, triethylamine, and water vapor adsorption on silicas of different origins, the surface layers of which contain functional groups of the ≡Si(CH2)2P(O)(OH)2 composition, namely, ethylene- and phenylene-bridged polysilsesquioxane xerogels produced by the sol-gel method, silica microspheres synthesized from tetraethoxysilane in the presence of [CH3(CH2)17N(CH3)3]Br as a template by spray-drying method, and SBA-15 mesoporous silica produced based on tetraethoxysilane using Pluronic 123 as a template. It is shown that all of the samples possess high specific surface areas, while the types of adsorption isotherms and the accessibility of active acidic sites for adsorption interactions with electron-donor molecules depend on the structures of pores and surface layers, which are governed by the methods of synthesis and postsynthesis sample treatment.
    Full-text · Article · May 2012 · Colloid Journal
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    Zub Yu.L. · Bruno Alonso · Abramov N.V. · Gorbik P.P. · I.V. Mel'nik
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    ABSTRACT: The developed methods using tetraethoxysilane and trifunctional silanes were applied to obtain Fe3O4 magnetic particles that contain amino groups with compositions of ≡Si(CH2)3NH2, ≡Si(CH2)3NH(CH2)2NH2, and [≡Si(CH2)3]2NH. The XRD data show that the nuclei of nanoparticles in the obtained materials preserve the structure of the primary carrier, namely, that of Fe3O4 magnetite. The thermograms show a high thermal stability of the applied surface layers, i.e., their destruction was found to start at temperature above 250°C. The DRIFT spectra indicate the formation of the silica bond framework in the surface layers of nanoparticles and also the existence of hydrogen bonds between amino groups and silanol groups with the participation of water molecules aided. All of the obtained materials exhibit magnetic properties and offer promising application in medicine.
    Full-text · Article · Feb 2012 · Glass Physics and Chemistry
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    ABSTRACT: We studied new mesoporous materials with original properties and obtained from self-assembled chitin–silica nano-composites. Our novel synthesis allows the controlled colloidal assembly of α-chitinnanorods (bundles of elongated chitin monocrystals) and siloxane oligomers. Calcination of nano-composites results in mesoporous silica materials. Their pore volume fraction POR (0–0.52) is strongly correlated to the initial chitin content. Using N2 sorption and TEM data, we identify and characterize primary and secondary textural units related to the imprints of chitin monocrystals (2.5 nm wide) and nanorods (20–30 nm wide) respectively. Primary textural units are preserved over a wide POR range (linear relationship between pore volume and specific surface area). The coating of monocrystals by siloxane oligomers leads to a siloxane network of fractal nature as deduced from complementary SAXS data. Beyond a critical value POR′ estimated near 0.2, the coating is partial, and the porosity becomes more open and connected. At larger scales, the arrangements of secondary textural units result in complex textures and long-range ordering, showing similarities with textural features found in natural materials. We discuss the competition between entropy-driven transitions typical of anisotropic particles and kinetic arrest due to colloidal gelation and inorganic condensation. Finally, a schematic model for texture formation is given.
    No preview · Article · Oct 2011 · Journal of Materials Chemistry
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    ABSTRACT: We explored the sensitivity of the (14)N quadrupolar interaction toward the characterization of surfactant-oxide interfaces. For the first time, experimental (14)N NMR spectra are recorded, modeled, and compared for three different mesostructured silica (hexagonal p6mm, cubic Ia3d, and lamellar) templated by hexadecyltrimethylammonium cations (CTA(+)). Broad distributions in quadrupolar coupling constant C(Q) are obtained showing differences between phases. In parallel, quantum chemical calculations using the Born-Oppenheimer molecular dynamics in combination with DFT have been successfully undertaken in a time scale of 25-32 ps to better understand the experimental results. From the two simulated models (CTA(+) alone vs CTA(+) in interaction with a D4R(-) silicate oligomer), we evidenced the relative effect of fast conformational variations and of intermolecular interactions on the time-averaged quadrupolar parameters. (14)N relaxation and (13)C CSA NMR data are also briefly presented and discussed. Our approach opens new directions for studying a wide range of mesostructured materials.
    No preview · Article · Sep 2011 · The Journal of Physical Chemistry C
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    ABSTRACT: A new route to synthesize hybrid silica-based network with bridging organic units via molecular recognition is described. The hydrolysis of two monosilylated complementary base pairs, one bearing an adenine fragment and the other a thymine fragment leads to the formation of a powdered sample that has been characterized by Scanning Electron Microscopy (SEM), Powder X-ray Diffraction (PXRD) FTIR and solid state NMR (1H, 13C and 29Si). This last technique proved to be extremely powerful to directly demonstrate the occurrence of heteroassembly of the nucleobase-based silylated fragments, through the use of two-dimensional 1H double-quanta MAS-NMR that could probe spatial proximities between the thymine NH groups and the adenine NH2 groups.
    No preview · Article · Jan 2011 · MRS Online Proceeding Library

Publication Stats

3k Citations
340.30 Total Impact Points


  • 2007-2015
    • Institut Charles Gerhardt
      Montpelhièr, Languedoc-Roussillon, France
    • Miltenyi Biotec GmbH
      Bergisch Gladbach, North Rhine-Westphalia, Germany
  • 2003-2012
    • French National Centre for Scientific Research
      • Institut des Matériaux Jean Rouxel
      Lutetia Parisorum, Île-de-France, France
  • 2005
    • CNRS Orleans Campus
      Orléans, Centre, France
  • 1993-2001
    • Pierre and Marie Curie University - Paris 6
      • Laboratoire de Chimie de la Matière Condensée de Paris (LCMCP)
      Paris, Ile-de-France, France