Phonon effects on x-ray absorption and nuclear magnetic resonance spectroscopies

In material sciences, spectroscopic approaches combining ab initio calculations with experiments are commonly used to accurately analyze the experimental spectral data. Most state-of-the-art first-principle calculations are usually performed assuming an equilibrium static lattice. Yet, nuclear motion affects spectra even when reduced to the zero-point motion at 0 K. We propose a framework based on Density-Functional Theory that includes quantum thermal fluctuations in theoretical X- ray Absorption Near-Edge Structure (XANES) and solid-state Nuclear Magnetic Resonance (NMR) spectroscopies and allows to well describe temperature effects observed experimentally. Within the Born-Oppenheimer and quasi-harmonic approximations, we incorporate the nuclear motion by generating several non-equilibrium configurations from the dynamical matrix. The averaged calculated XANES and NMR spectral data have been compared to experiments in MgO, proof-of-principle compound. The good agreement obtained between experiments and calculations validates the developed approach, which suggests that calculating the XANES spectra at finite temperature by averaging individual non-equilibrium configurations is a suitable approximation. This study high- lights the relevance of phonon renormalization and the relative contributions of thermal expansion and nuclear dynamics on NMR and XANES spectra on a wide range of temperatures.Comment: 13 pages, 6 figures, 1 appendi

Structural characterization of SiO2-Na2O-CaO-B2O3-MoO3 glasses

5 pagesNuclear spent fuel reprocessing generates high level radioactive waste with high Mo concentration that are currently immobilized in borosilicate glass matrices containing both alkali and alkaline-earth elements [1]. Because of its high field strength, Mo6+ ion has a limited solubility in silicate and borosilicate glasses and crystallization of alkali or alkaline-earth molybdates can be observed during melt cooling or heat treatment of glasses [2-4]. Glass composition changes can significantly modify the nature and the relative proportions of molybdate crystals that may form during natural cooling of the melt. For instance, in a previous work we showed that CaMoO4 crystallization tendency increased at the expenses of Na2MoO4 when B2O3 concentration increased in a SiO2-Na2O-CaO-MoO3 glass composition [4]. In this study, we present structural results on two series (Mx, By) of quenched glass samples belonging to this system using 29Si, 11B, 23Na MAS NMR and Raman spectroscopies. The effect of MoO3 on the glassy network structure is studied and its structural role is discussed (Mx series). The evolution of the distribution of Na+ ions within the borosilicate network is followed when B2O3 concentration increased (By series) and is discussed according to the evolution of the crystallization tendency of the melt. For all glasses, ESR was used to investigate the nature and the concentration of paramagnetic species

Solid state NMR characterization of phenylphosphonic acid encapsulated in SBA-15 and aminopropyl-modified SBA-15

5th International Conference of theă Federation-of-European-Zeolite-Associations (FEZA), Valencia, SPAIN, JULă 03-07, 2011International audienceWe present in this communication that phenyl phosphonic acid can be efficiently loaded in mesoporous SBA-15 and aminopropyl-modified SBA powdered samples through the incipient wetness impregnation method. High amount of phosphonic acid can be reach up to 380 mg/g of sample. We use multinuclear solid state NMR as a method of choice for the indeep characterization of the samples. Thus we demonstrate that phosphonic acid molecules do not crystallize inside the pores. The molecules are highly mobile in SBA-15 because they are submitted to a confinement effect due to the mesoscopic size of the pores and consequently they exhibit a weak interaction with the silica walls. In the case of aminopropyl-modified SBA material, we show that the molecules are rigid and that they are in strong interaction with the aminopropyl groups. Moreover, a 2D double quantum 1H NMR experiment recorded at high field and high spinning speed permit to propose a model of the phosphonate-aminopropyl interaction. The increase in spectral resolution due to the combination of high magnetic field and fast MAS rate allows also the assignment of 1H resonances in aminopropyl-modified SBA matrix and notably allows the assignment of the protons resonance of the amino group

A Molecular Picture of the Adsorption of Glycine in Mesoporous Silica through NMR Experiments Combined with DFT‑D Calculations

International audienceThe adsorption behavior of the amino acid glycine in mesoporous silica has been investigated using a combination of quantum chemical calculations and NMR spectroscopy experiments. Glycine adsorption on two representative sites of an amorphous silica surface, vicinal silanols and a silanol nest, was investigated by DFT-D. The effect of water coadsorption on the energetics of adsorption and NMR shifts was characterized. It was found that the silanol nest is a more favorable site for glycine adsorption due to a local increased H-bond density. Co-adsorption with water is also favored, especially a water molecule between a SiOH and the ammonium moiety. NMR chemical shifts computed on these models fall into the observed 13C and 15N experimental range, suggesting that the presence of different energetically comparable adsorption configurations cannot be excluded

Determination of the antisymmetric part of the chemical shift anisotropy tensor via spin relaxation in nuclear magnetic resonance

Relaxation processes induced by the antisymmetric part of the chemical shift anisotropy tensor (henceforth called anti-CSA) are usually neglected in NMR relaxation studies. It is shown here that anti-CSA components contribute to longitudinal relaxation rates of the indole N-15 nucleus in tryptophan in solution at different magnetic fields and temperatures. To determine the parameters of several models for rotational diffusion and internal dynamics, we measured the longitudinal relaxation rates R-1=1/T-1 of N-15, the N-15-H-1 dipole-dipole (DD) cross-relaxation rates (Overhauser effects), and the cross-correlated CSA/DD relaxation rates involving the second-rank symmetric part of the CSA tensor of N-15 at four magnetic fields B-0=9.4, 14.1, 18.8, and 22.3 T (400, 600, 800, and 950 MHz for protons) over a temperature range of 270<T<310 K. A good agreement between experimental and theoretical, rates can only be obtained if the CSA tensor is assumed to comprise first-rank antisymmetric (anti-CSA) components. The magnitude of the hitherto neglected antisymmetric components is of the order of 10% of the CSA. (C) 2010 American Institute of Physics. [doi:10.1063/1.3445777

Effet de la nature des ions alcalins et alcalino-terreux sur la structure d'un verre riche en terre

Dans le cadre d'une étude structurale d'un verre de confinement de déchets nucléaires de type aluminoborosilicate et riche en terres rares, l'influence de la nature des ions alcalins ou alcalino-terreux est analysée. Pour cela deux séries de verres ont été élaborées dans lesquelles l'ion Na+ (respectivement l'ion Ca2+) présent dans la composition de référence, est totalement substitué par un autre ion alcalin Li+, K+, Rb+ ou Cs+ (respectivement un autre ion alcalino-terreux Mg2+, Sr2+ ou Ba2+). Ces verres, analysés par spectroscopie d'absorption optique, Raman et RMN 27Al et 11B, ont permis de montrer le fort impact de la nature de l'ion modificateur aussi bien sur la structure du réseau vitreux ( variation du rapport BO3/BO4 et variations locales du degré de polymérisation) que de l'environnement local de la terre rare (diminution du degré de covalence de la liaison Nd-O avec l'augmentation de la force de champ de l'ion modificateur)

CT pelvimetry of variant pelvis and child birth prognosis

The aim of this study was to determine the threshold values of pelvimetry by scanning and to evaluate the ability of the pelvimetry alone to diagnose a fetal-pelvic disproportion. It was an observational retrospective study on 410 pregnant women who had a scanner pelvimetry for any reasons. Based on the fetal presentations, two subgroups (breech and cephalic -others) have been defined. Measurements of the main obstetric diameters (promonto-retropubic, median transverse and dual sciatica) were taken. The 5th and 10th percentile were calculated as well as the 90th and 95th to determine the threshold values of pelvimetry by scanner. The scanner values found on CT were compared with the standard X ray pelvimetry values. Referring to extreme values obtained by pelvimetry scanner, some pathological pelvic brim were reconstructed in 3D. Moreover, the delivery prognostic was analyzed by crossing the pelvic inlet dimensions (Magnin index) and pelvic outlet dimensions (bi-sciatic diameter) with the outcome of the delivery. The mean values of the scanno-pelvimetry measurement in our series were:m12,39 cm (± 1) for the promonto-retropubic diameter, 12.88 cm (± 1.01) for the transverse median diameter and 11 cm (± 1.32) for the bi-sciatic diameter. These measurements provided an accuracy less than 1 cm compared to the standard ray pelvimetry. Although Magnin index at 23 allows a vaginal delivery, 51% of oursample have failed. Moreover, for the Magnin index at 24 and 25, the vaginal delivery failure rate remains high:45.1% and 39.61% respectively. Compared to classical pelvimetry, pelvimetry by scanner provides additional precision and allows to study the geometry of the basin. However, the pelvimetry alone could not be effective to establish the prognosis of vaginal delivery.Keywords: scanno-pelvimetry, prognosis, deliver

Synthesis of metal-free lightweight materials with sequence-encoded properties

[EN] A high-temperature solid-state synthesis is a widespread tool for the construction of metal-free materials, owing to its simplicity and scalability. However, no method is currently available for the synthesis of metal-free materials, which enables control over the atomic ratio and spatial organization of several heteroatoms. Here we report a general and large-scale synthesis of phosphorus-nitrogen-carbon (PNC) materials with highly controllable elemental composition and structural, electronic, and thermal stability properties. To do so, we designed four different crystals consisting of melamine and phosphoric acid with different monomers sequences as the starting precursors. The monomer sequence of the crystals is preserved upon calcination (up to 800 degrees C) to an unprecedented degree, which leads to precise control over the composition of the final PNC materials. The latter exhibit a remarkable stability up to 970 degrees C in air, positioning them as sustainable, lightweight supports for catalysts in high-temperature reactions as well as halogen-free fire-retardant materials.The authors would like to thank Dr Volodiya Ezersky, Dr Natalya Froumin, Dr Anna Milionshchik, Dr Radion Vainer, Dr Einat Nativ-Roth, and Mr Nitzan Shauloff for analytical HRTEM, XPS, TGA, SC-XRD, HRSEM, and technical support, respectively. This research was partly funded by the following: the Planning & Budgeting Committee/Israel Council for Higher Education (CHE) and Fuel Choice Initiative (Prime Minister Office of Israel), within the framework of "Israel National Research Center for Electrochemical Propulsion" (INREP); the Minerva Center No. 117873; the Spanish Ministerio de Economia y Competitividad (MAT2016-77608-C3-1-P, MAT2016-75883-C2-2-P); J. A. and H. G. also gratefully acknowledges financial support from the Spanish Ministry of Economy and Competitiveness (Severo Ochoa SEV2016-0683 and RTI2018-89023-CO2-R1) and by the Generalitat Valenciana (Prometeo 2017-083). This project has received funding from the European Research Council (ERC) under the European Union's Horizon 2020 Research and Innovation Programme (grant agreement No. [849068]). NMR spectroscopic calculations were performed using HPC resources from GENCI-IDRIS (Grant 097535). The French Region Ile de France-SESAME program is acknowledged for financial support (700 MHz spectrometer).Azoulay, A.; Barrio, J.; Tzadikov, J.; Volokh, M.; Albero-Sancho, J.; Gervais, C.; Amo-Ochoa, P.... (2020). Synthesis of metal-free lightweight materials with sequence-encoded properties. Journal of Materials Chemistry A. 8(17):8752-8760. https://doi.org/10.1039/d0ta03162c87528760817Paraknowitsch, J. P., & Thomas, A. (2013). Doping carbons beyond nitrogen: an overview of advanced heteroatom doped carbons with boron, sulphur and phosphorus for energy applications. Energy & Environmental Science, 6(10), 2839. doi:10.1039/c3ee41444bGates, D. P. (2003). Chemistry and Applications of Polyphosphazenes. By Harry R. Allcock. Angewandte Chemie International Edition, 42(38), 4570-4570. doi:10.1002/anie.200385981Cruz-Silva, E., Cullen, D. A., Gu, L., Romo-Herrera, J. M., Muñoz-Sandoval, E., López-Urías, F., … Terrones, M. (2008). Heterodoped Nanotubes: Theory, Synthesis, and Characterization of Phosphorus−Nitrogen Doped Multiwalled Carbon Nanotubes. ACS Nano, 2(3), 441-448. doi:10.1021/nn700330wZhang, W., Barrio, J., Gervais, C., Kocjan, A., Yu, A., Wang, X., & Shalom, M. (2018). Synthesis of Carbon-Nitrogen-Phosphorous Materials with an Unprecedented High Amount of Phosphorous toward an Efficient Fire-Retardant Material. Angewandte Chemie International Edition, 57(31), 9764-9769. doi:10.1002/anie.201805279Velencoso, M. M., Battig, A., Markwart, J. C., Schartel, B., & Wurm, F. R. (2018). Molecular Firefighting—How Modern Phosphorus Chemistry Can Help Solve the Challenge of Flame Retardancy. Angewandte Chemie International Edition, 57(33), 10450-10467. doi:10.1002/anie.201711735Li, C., Chen, Z., Kong, A., Ni, Y., Kong, F., & Shan, Y. (2018). High-rate oxygen electroreduction over metal-free graphene foams embedding P–N coupled moieties in acidic media. Journal of Materials Chemistry A, 6(9), 4145-4151. doi:10.1039/c7ta08186cChaplin, A. B., Harrison, J. A., & Dyson, P. J. (2005). Revisiting the Electronic Structure of Phosphazenes. Inorganic Chemistry, 44(23), 8407-8417. doi:10.1021/ic0511266Guo, S., Deng, Z., Li, M., Jiang, B., Tian, C., Pan, Q., & Fu, H. (2015). Phosphorus-Doped Carbon Nitride Tubes with a Layered Micro-nanostructure for Enhanced Visible-Light Photocatalytic Hydrogen Evolution. Angewandte Chemie International Edition, 55(5), 1830-1834. doi:10.1002/anie.201508505Feng, L.-L., Zou, Y., Li, C., Gao, S., Zhou, L.-J., Sun, Q., … Zou, X. (2014). Nanoporous sulfur-doped graphitic carbon nitride microrods: A durable catalyst for visible-light-driven H 2 evolution. International Journal of Hydrogen Energy, 39(28), 15373-15379. doi:10.1016/j.ijhydene.2014.07.160Barrio, J., Lin, L., Amo-Ochoa, P., Tzadikov, J., Peng, G., Sun, J., … Shalom, M. (2018). Unprecedented Centimeter-Long Carbon Nitride Needles: Synthesis, Characterization and Applications. Small, 14(21), 1800633. doi:10.1002/smll.201800633Faul, C. F. J., & Antonietti, M. (2003). Ionic Self-Assembly: Facile Synthesis of Supramolecular Materials. Advanced Materials, 15(9), 673-683. doi:10.1002/adma.200300379Barrio, J., & Shalom, M. (2018). Rational Design of Carbon Nitride Materials by Supramolecular Preorganization of Monomers. ChemCatChem, 10(24), 5573-5586. doi:10.1002/cctc.201801410De Ridder, D. J. A., Goubitz, K., Brodski, V., Peschar, R., & Schenk, H. (2004). Crystal Structure of Melaminium Orthophosphate from High-Resolution Synchrotron Powder-Diffraction Data. Helvetica Chimica Acta, 87(7), 1894-1905. doi:10.1002/hlca.200490168Li, X.-M., Feng, S.-S., Wang, F., Ma, Q., & Zhu, M.-L. (2009). Bis(2,4,6-triamino-1,3,5-triazin-1-ium) hydrogen phosphate trihydrate. Acta Crystallographica Section E Structure Reports Online, 66(1), o239-o240. doi:10.1107/s1600536809054798Jürgens, B., Irran, E., Senker, J., Kroll, P., Müller, H., & Schnick, W. (2003). Melem (2,5,8-Triamino-tri-s-triazine), an Important Intermediate during Condensation of Melamine Rings to Graphitic Carbon Nitride:  Synthesis, Structure Determination by X-ray Powder Diffractometry, Solid-State NMR, and Theoretical Studies. Journal of the American Chemical Society, 125(34), 10288-10300. doi:10.1021/ja0357689Barrio, J., Grafmüller, A., Tzadikov, J., & Shalom, M. (2018). Halogen-hydrogen bonds: A general synthetic approach for highly photoactive carbon nitride with tunable properties. Applied Catalysis B: Environmental, 237, 681-688. doi:10.1016/j.apcatb.2018.06.043Zhao, Y. C., Yu, D. L., Zhou, H. W., Tian, Y. J., & Yanagisawa, O. (2005). Turbostratic carbon nitride prepared by pyrolysis of melamine. Journal of Materials Science, 40(9-10), 2645-2647. doi:10.1007/s10853-005-2096-3Naik, A. D., Fontaine, G., Samyn, F., Delva, X., Louisy, J., Bellayer, S., … Bourbigot, S. (2014). Outlining the mechanism of flame retardancy in polyamide 66 blended with melamine-poly(zinc phosphate). Fire Safety Journal, 70, 46-60. doi:10.1016/j.firesaf.2014.08.019Guo, M., Huang, J., Kong, X., Peng, H., Shui, H., Qian, F., … Zhang, Q. (2016). Hydrothermal synthesis of porous phosphorus-doped carbon nanotubes and their use in the oxygen reduction reaction and lithium-sulfur batteries. New Carbon Materials, 31(3), 352-362. doi:10.1016/s1872-5805(16)60019-7Wu, J., Yang, S., Li, J., Yang, Y., Wang, G., Bu, X., … Xie, X. (2016). Electron Injection of Phosphorus Doped g-C3N4Quantum Dots: Controllable Photoluminescence Emission Wavelength in the Whole Visible Light Range with High Quantum Yield. Advanced Optical Materials, 4(12), 2095-2101. doi:10.1002/adom.201600570Fukushima, A., Hayashi, A., Yamamura, H., & Tatsumisago, M. (2017). Mechanochemical synthesis of high lithium ion conducting solid electrolytes in a Li2S-P2S5-Li3N system. Solid State Ionics, 304, 85-89. doi:10.1016/j.ssi.2017.03.010Xie, M., Tang, J., Kong, L., Lu, W., Natarajan, V., Zhu, F., & Zhan, J. (2019). Cobalt doped g-C3N4 activation of peroxymonosulfate for monochlorophenols degradation. Chemical Engineering Journal, 360, 1213-1222. doi:10.1016/j.cej.2018.10.130Goli, P., Legedza, S., Dhar, A., Salgado, R., Renteria, J., & Balandin, A. A. (2014). Graphene-enhanced hybrid phase change materials for thermal management of Li-ion batteries. Journal of Power Sources, 248, 37-43. doi:10.1016/j.jpowsour.2013.08.135Wulff, G., Schmidt, H., & Zhu, L. (1999). Generating hydrophilic surfaces on standard polymers after copolymerization with low amounts of protected vinyl sugars. Macromolecular Chemistry and Physics, 200(4), 774-782. doi:10.1002/(sici)1521-3935(19990401)200:43.0.co;2-jXu, J., Zhang, L., Shi, R., & Zhu, Y. (2013). Chemical exfoliation of graphitic carbon nitride for efficient heterogeneous photocatalysis. Journal of Materials Chemistry A, 1(46), 14766. doi:10.1039/c3ta13188bKulkarni, G. U., Laruelle, S., & Roberts, M. W. (1996). The oxygen state active in the catalytic oxidation of carbon monoxide at a caesium surface: isolation of the reactive anionic CO2δ–species. Chem. Commun., (1), 9-10. doi:10.1039/cc9960000009Wang, L., Wang, C., Hu, X., Xue, H., & Pang, H. (2016). Metal/Graphitic Carbon Nitride Composites: Synthesis, Structures, and Applications. Chemistry - An Asian Journal, 11(23), 3305-3328. doi:10.1002/asia.201601178Barrio, J., Mateo, D., Albero, J., García, H., & Shalom, M. (2019). A Heterogeneous Carbon Nitride–Nickel Photocatalyst for Efficient Low‐Temperature CO 2 Methanation. Advanced Energy Materials, 9(44), 1902738. doi:10.1002/aenm.201902738Alrafei, B., Polaert, I., Ledoux, A., & Azzolina-Jury, F. (2020). Remarkably stable and efficient Ni and Ni-Co catalysts for CO2 methanation. Catalysis Today, 346, 23-33. doi:10.1016/j.cattod.2019.03.026Yang Lim, J., McGregor, J., Sederman, A. J., & Dennis, J. S. (2016). Kinetic studies of CO 2 methanation over a Ni/ γ -Al 2 O 3 catalyst using a batch reactor. Chemical Engineering Science, 141, 28-45. doi:10.1016/j.ces.2015.10.026Mateo, D., Albero, J., & García, H. (2018). Graphene supported NiO/Ni nanoparticles as efficient photocatalyst for gas phase CO2 reduction with hydrogen. Applied Catalysis B: Environmental, 224, 563-571. doi:10.1016/j.apcatb.2017.10.071Dolomanov, O. V., Bourhis, L. J., Gildea, R. J., Howard, J. A. K., & Puschmann, H. (2009). OLEX2: a complete structure solution, refinement and analysis program. Journal of Applied Crystallography, 42(2), 339-341. doi:10.1107/s0021889808042726Sheldrick, G. M. (2015). SHELXT– Integrated space-group and crystal-structure determination. Acta Crystallographica Section A Foundations and Advances, 71(1), 3-8. doi:10.1107/s2053273314026370Sheldrick, G. M. (2015). Crystal structure refinement withSHELXL. Acta Crystallographica Section C Structural Chemistry, 71(1), 3-8. doi:10.1107/s2053229614024218Kresse, G., & Hafner, J. (1994). Ab initiomolecular-dynamics simulation of the liquid-metal–amorphous-semiconductor transition in germanium. Physical Review B, 49(20), 14251-14269. doi:10.1103/physrevb.49.14251Pack, J. D., & Monkhorst, H. J. (1977). «Special points for Brillouin-zone integrations»—a reply. Physical Review B, 16(4), 1748-1749. doi:10.1103/physrevb.16.1748Blöchl, P. E., Jepsen, O., & Andersen, O. K. (1994). Improved tetrahedron method for Brillouin-zone integrations. Physical Review B, 49(23), 16223-16233. doi:10.1103/physrevb.49.16223Baroni, S., de Gironcoli, S., Dal Corso, A., & Giannozzi, P. (2001). Phonons and related crystal properties from density-functional perturbation theory. Reviews of Modern Physics, 73(2), 515-562. doi:10.1103/revmodphys.73.515Perdew, J. P., Burke, K., & Ernzerhof, M. (1996). Generalized Gradient Approximation Made Simple. Physical Review Letters, 77(18), 3865-3868. doi:10.1103/physrevlett.77.3865Troullier, N., & Martins, J. L. (1991). Efficient pseudopotentials for plane-wave calculations. Physical Review B, 43(3), 1993-2006. doi:10.1103/physrevb.43.1993Kleinman, L., & Bylander, D. M. (1982). Efficacious Form for Model Pseudopotentials. Physical Review Letters, 48(20), 1425-1428. doi:10.1103/physrevlett.48.1425Pickard, C. J., & Mauri, F. (2001). All-electron magnetic response with pseudopotentials: NMR chemical shifts. Physical Review B, 63(24). doi:10.1103/physrevb.63.245101Lejaeghere, K., Bihlmayer, G., Björkman, T., Blaha, P., Blügel, S., Blum, V., … Dal Corso, A. (2016). Reproducibility in density functional theory calculations of solids. Science, 351(6280). doi:10.1126/science.aad300

From crystalline to amorphous calcium pyrophosphates:a solid state Nuclear Magnetic Resonance perspective

Hydrated calcium pyrophosphates (CPP, Ca2P2O7·nH2O) are a fundamental family of materials among osteoarticular pathologic calcifications. In this contribution, a comprehensive multinuclear NMR (Nuclear Magnetic Resonance) study of four crystalline and two amorphous phases of this family is presented. 1H, 31P and 43Ca MAS (Magic Angle Spinning) NMR spectra were recorded, leading to informative fingerprints characterizing each compound. In particular, different 1H and 43Ca solid state NMR signatures were observed for the amorphous phases, depending on the synthetic procedure used. The NMR parameters of the crystalline phases were determined using the GIPAW (Gauge Including Projected Augmented Wave) DFT approach, based on first-principles calculations. In some cases, relaxed structures were found to improve the agreement between experimental and calculated values, demonstrating the importance of proton positions and pyrophosphate local geometry in this particular NMR crystallography approach. Such calculations serve as a basis for the future ab initio modeling of the amorphous CPP phases. Statement of significance The general concept of NMR crystallography is applied to the detailed study of calcium pyrophosphates (CPP), whether hydrated or not, and whether crystalline or amorphous. CPP are a fundamental family of materials among osteoarticular pathologic calcifications. Their prevalence increases with age, impacting on 17.5% of the population after the age of 80. They are frequently involved or associated with acute articular arthritis such as pseudogout. Current treatments are mainly directed at relieving the symptoms of joint inflammation but not at inhibiting CPP formation nor at dissolving these crystals. The combination of advanced NMR techniques, modeling and DFT based calculation of NMR parameters allows new original insights in the detailed structural description of this important class of biomaterials

Solid-state nuclear magnetic resonance: A valuable tool to explore organic-inorganic interfaces in silica-based hybrid materials

International audienc