Code: PS	Time Slot/Poster Number: 390	Session: Solids: Inorganics & Materials, Poster
The Microscopic and Mesoscopic Structure and Dynamics of Nafion Investigated with NMR Spectroscopy, Micro-Imaging and Molecular Dynamics Simulation
Shangwu Ding1; Zhen Wu1; Peter Po-Jen Chu2
1National Sun Yat-sen University, Kaohsiung, Taiwan; 2Dept. of Chem., National Central University, Chungli, Taiwan
Abstract
Nafion is the most commonly used ion exchange membrane for fuel cells because of its excellent proton conductivity and thermal, electrochemical and mechanical stability. To understand the structure and dynamics of this unique material has been the focus of many studies with various techniques. However, many questions remain, e.g., the real mechanism of proton transport, the structure at the mesoscopic scale (from ~50 nm to ~10 μm), the correlation and interaction of structure and dynamics at different scales from Angstrom to millimeter. In this work, we report the results about the structure and dynamics of Nafion at two different scales, i.e., microscopic and mesoscopic, with solid and liquid state NMR spectroscopy, micro-imaging and molecular dynamics simulation.

Code: PS	Time Slot/Poster Number: 391	Session: Solids: Inorganics & Materials, Poster
Correlating Structural and Electronic Changes in a Phenalenyl-Based Neutral Radical Conductor via Solid-State NMR
Arun Agarwal; Sushanta Pal; Robert Haddon; Leonard Mueller
UC Riverside, Riverside, CA
Abstract
The butyl-substituted spiro-phenalenyl radical is a member of a new class of organic conductors based on neutral radicals with the highest conductivities of any neutral organic molecular solid. At room temperature, this compound exists as a diamagnetic pi-dimer (inter-planar separation of ~3.1 Å), but then undergoes a phase transition to a paramagnetic pi-dimer (inter-planar separation of ~3.3 Å) at 340K. 13C chemical shift measurements allow us to track the transition between the diamagnetic and paramagnetic states, which we find builds in as a gradual increase in the spin-density at the aromatic sites and a decrease in the electron spin-spin coupling between adjacent radicals. These correlate with the changes in the inter-planar separation as a function of temperature.

Code: PS	Time Slot/Poster Number: 392	Session: Solids: Inorganics & Materials, Poster
Characterizing Hydrogen Storage Media: Understanding the Interior Pore Structure of a Cu2BTC3 Metal-Organic Framework Infiltrated with NaAlH4
Afram Kirmiz1; Raghunandan Bhakta2; Mark Allendorf2; Richard Behrens2; Eric Majzoub3; Julie Herberg1
1Lawrence Livermore National Laboratory, Livermore, CA; 2Sandia National Laboratories, Livermore, CA; 3University of Missouri, St. Louis, St. Louis, MO
Abstract
Copper benzene tricarboxylate (Cu2BTC3) metal organic frameworks (MOF) are investigated before and after infiltration with sodium alanate as a hydrogen storage medium. Preliminary results indicate favorable adsorption and desorption of H2 in comparison to that of bulk sodium alanate. MOF samples are studied with 1H, 13C, 23Na, and 27Al magic angle spinning nuclear magnetic resonance (MAS NMR) spectroscopy to understand the structure and environment of the sodium alanate infiltrated within the MOF porous structure. Preliminary results indicate the presence of nanometer-scale sodium alanate clusters within the pores of the MOF, and that the MOF structure is retained after infiltration of sodium alanate with tetrahydrofuran (THF) into the MOF.

Code: PS	Time Slot/Poster Number: 393	Session: Solids: Inorganics & Materials, Poster
Solid State NMR Studies of the Site-Selective Inclusion Complexation Between β-Cyclodextrin and Poly(ethylene oxide)-block-poly(propylene oxide)-block-poly(ethylene oxide) Copolymers
Mingming Guo; Chi-Chun Tsai; Stephen Z. D. Cheng
Departmnet of Polymer Science, University of Akron, Akron, OH
Abstract
A series of inclusion complexes of poly(PEO-b-PPO-b-PEO) with β-cyclodextrin (β-CD) was prepared. Their formation, structure and dynamics were investigated by solution 2D ROESY as well as 1D and 2D Solid-state NMR. The inclusion complexes were formed in aqueous solution detected by 2D ROESY. The high efficiency of cross-polarization and spin diffusion experiments in 13C solid state NMR showed that the mobility of PPO block dramatically decreases after β-CDs are incorporated into the PPO chains. The hydrophobic inside cavities of β-CDs restrict the PPO block mobility, indicating that the formation of inclusion complexes in the solid state. The 2D wide-line separation NMR experiments suggested that β-CDs only thread onto PPO blocks while forming the inclusion complexes.

Code: PS	Time Slot/Poster Number: 394	Session: Solids: Inorganics & Materials, Poster
Assessing the use of 7Li MAS NMR Spectral Simulations for the Characterization of Disorder in Lithium Containing Materials
Todd M. Alam; Sarah K. McIntyre; Emily Baldwin; Amy Garner; May Nyman
Sandia National Laboratories, Albuquerque, NM
Abstract
In this poster, we will explore the use of 7Li MAS NMR spectral line shape analysis for measuring the distribution of the quadrupolar interaction in disorder materials. There have been several recent examples on other quadrupolar nuclei that utilize variations in second-order quadrupolar line shapes to determine distributions. For 7Li NMR, the quadrupolar coupling is much smaller, with the spectra being dominated by first order quadrupolar effects. This makes the measurement of interaction distributions more difficult, and is an area that has not been extensively investigated. We will explore the error surfaces of simple Gaussian and Czjzek distributions for several experimental samples to address the utility of this type of 7Li MAS NMR analyses.

Code: PS	Time Slot/Poster Number: 395	Session: Solids: Inorganics & Materials, Poster
NMR Characterization of Triflic Acid-activated Brazilian Al-pillared Clays
Anderson C.O. Silva1; Rosane A. S. San Gil1; Lidia C. Dieguez2
1Instituto de Quimica, Universidade Federal do Rio, Rio De Janeiro, Brazil; 2PEQ/COPPE, Universidade Federal do Rio de Janeiro, Rio de Janeiro, Brazil
Abstract
NMR techniques showed to be powerful tools for characterizing clay-based heterogeneous catalysts. In this communication the modifications in the structure of Brazilian Al-pillared clays (Al-PILCs) after treatment with triflic acid (TfOH) were followed by Si-29, Al-27 and C-13 solid state NMR, DRX, frontal NH3 adsorption and TG analysis. The Al-27 and Si-29 MAS NMR results confirmed that part of the clay structure was lost, with amorphous silica generation. From C-13 MAS-NMR data, the presence of intact triflate groups within the structure of the acid Al-PILC was confirmed.

Code: PS	Time Slot/Poster Number: 396	Session: Solids: Inorganics & Materials, Poster
95Mo MAS NMR of MoS2 Reveals Precise 95Mo Anisotropic Parameters from Its Central and Satellite Transitions
Hans Jorgen Jakobsen1; Jørgen Skibsted1; Henrik Bildsoe1; Michael Brorson3; Kjeld Schaumburg2
1Department of Chemistry, Dk-8000 Aarhus C, Denmark; 2CISMI, Roskilde University, 4000 Roskilde, Denmark; 3Haldor Topsøe A/S, 2800 Lyngby, Denmark
Abstract
MoS2 has important industrial applications as solid lubricant and as the active component in heterogeneous hydrodesulfurization catalysts. Previous solid-state 95Mo NMR studies of this important material have produced inconsistent or strange results. Here we report the recording of the first complete 95Mo MAS NMR spectrum of MoS2, i.e. incorporating both the central and satellite transitions, for this spin I = 5/2 quadrupole at natural abundance and 14.1 T. Analysis of this highly complex MAS spectrum using STARS allows precise values for the 95Mo anisotropic parameters to be retrieved. A quite large 95Mo quadrupole coupling (3.61 MHz) and an unusually large 95Mo chemical shift anisotropy (1,018 ppm) characterize the Mo atoms in the layered structure of MoS2.

Code: PS	Time Slot/Poster Number: 397	Session: Solids: Inorganics & Materials, Poster
Efficient MAS 23Na-29Si HMQC dipolar correlation experiment based on the SR412 recoupling scheme for the spectral editing of multiphased systems
Laura Martel; Michael Deschamps; Franck Fayon; Emmanuel Veron; Dominique Massiot
CEMHTI-CNRS, Orleans, France
Abstract
The preparation of sodium silicates usually leads to the formation of several polymorphs which are heat treatment dependent. The 23Na MAS NMR spectra are very complicated due to the strong overlapping of the different signals. We propose a new technique to separate their respective contributions using a HMQC with SR412 symmetry based pulses for the recoupling of the 23Na-29Si dipolar interaction. This supercycled experiment is constructed from the basic R412 sequence made of four Pi-pulses with alternating phases +/-90°. Previous 29Si MAS NMR experiments allowed us to attribute the different signals to their corresponding crystals: Three separate phases can be assigned to the two polymorphs alpha and delta of sodium disilicate (Na2Si2O5) and to the sodium metasilicate (Na2SiO3).

Code: PS	Time Slot/Poster Number: 398	Session: Solids: Inorganics & Materials, Poster
« Solid State NMR/GIPAW/VASP » Method: The Study Case of Pure and Carbonated Hydroxyapatite Structures
Fabien Aussenac1; Gerhard Althoff2; Christel Gervais3; Florence Babonneau3; Satoshi Hayakawa4; Akiyoshi Osaka4; Christian Bonhomme3
1Bruker Biospin, Wissembourg, France; 2Bruker Biospin GmbH, Rheinstetten, Germany; 3Laboratoire de Chimie de la Matière Condensée CNRS, Paris, France; 4Biomaterials Laboratory, Okayama, Japan
Abstract
In this communication, a detailed analysis of pure hydroxyapatite (HAp, Ca10(PO4)6(OH)2) and carbonated hydroxyapatite (CHAp) is presented by means of triple resonance MAS experiments, ab initio calculations of NMR parameters using the GIPAW method (Mauri and Pickard, 2001) and VASP models. This combined approach allows to fully understand the broadening of the 1H and 31P resonance lines in CHAp by taking into account A-, B- and A/B type substitutions (A stands for OH substitution, whereas B stands for PO4 substitution). Moreover, 13C chemical shifts are in good agreement with data already published in the literature. As a matter of fact, the “NMR/GIPAW/VASP” method can be extended virtually to any anionic and/or cationic substitution in apatitic structures.

Code: PS	Time Slot/Poster Number: 399	Session: Solids: Inorganics & Materials, Poster
Carbon Sequestration Mechanisms of Forsterite in Supercritical CO2 and H2O Studied by Solid State 29Si and 13C NMR Spectroscopy
David W Hoyt; Jian Zhi Hu; Ja Hun Kwak; Chongming Wang; Kevin Rosso; Andrew Felmy; Jesse Sears
Pacific Northwest National Lab, Richland, WA
Abstract
Burning fossil fuels such as coal, a major source of CO2 emissions to the atmosphere, appears to continue to provide a significant portion of total energy in both industrialized and developing countries. The widespread consensus in the scientific community is that increased levels of greenhouse gases, i.e., CO2, are adversely affecting the global environment. One proposed method for reducing CO2 emission is to store it underground in geologic repositories as a supercritical fluid.

Code: PS	Time Slot/Poster Number: 400	Session: Solids: Inorganics & Materials, Poster
Investigation of local dynamics and structure in additive fortified epoxy resins via solid-state NMR
Christoph Kins; Dymtro Dudenko; Gunther Brunklaus
MPI for Polymer Research, Mainz, Germany
Abstract
Though an incorporation of molecular additives represents a powerful tool for tailoring properties of polymers, the molecular nature of additive-polymer interactions is not yet fully understood. In this work, we present multinuclear solid-state NMR studies of amine-cured model epoxy resins, where selected fortifiers such as dimethyl methylphosphonate (DMMP) and DMSO were investigated. While DMSO-d6 revealed a rotational barrier of 20 kJ/mol comparable to solid DMSO-d6, DMMP yielded significant 13C and 31P chemical shift changes, thereby excluding fortification due to “mere” host-guest chemistry. Rather, complex additive-resin interactions and loss of fortification upon aging were identified. Interpretation of experimental NMR data was supported by ab initio DFT chemical shift and Nuclear Independent Chemical Shift map computations based on corresponding CPMD-derived model geometries.

Code: PS	Time Slot/Poster Number: 401	Session: Solids: Inorganics & Materials, Poster
7Li Microcoil MAS NMR Application to Cathode Materials for Thin-film Lithium Ion Batteries
Yasuto Noda1; Naoaki Kuwata2; Junichi Kawamura2; Hideki Maekawa3; Kazuyuki Takeda1
1Graduate School of Science, Kyoto University, Kyoto, Japan; 2IMRAM, Tohoku University, Sendai, Japan; 3Graduate School of Engineering, Tohoku University, Sendai, Japan
Abstract
In order to elucidate the structure of LiCoO2 cathode of thin-film lithium ion batteries formed on a glass substrate, a powder sample scratched off the substrate was studied with 7Li MAS NMR. Since the amount of the sample that can be gathered was severely limited, we fabricated a microcoil MAS probe using a coil with a diameter 0.8 mm, making measurement with a sample less than 0.1 mg feasible. The spectrum of the thin film showed a distinctly different shape from that of bulk used for its ingredient, indicating specific structure and/or electronic state in the thin-film. The result is a step toward structure determination, which would bring important information for improvement of thin-film lithium ion batteries.

Code: PS	Time Slot/Poster Number: 402	Session: Solids: Inorganics & Materials, Poster
Structure and dynamics in layered aluminium hydroxides from high-resolution solid-state NMR and first-principle calculations
Anastasia Vyalikh; Ulrich Scheler
Leibniz Institute of Polymer Research Dresden, Dresden, Germany
Abstract
Layered aluminium hydroxides find numerous applications. Insight into molecular mobility has been gained from 1H T1r experiments, shorter T1r is observed for protons with a higher Al content in the vicinity. Evidence for two sites of differing quadrupole coupling constants in LDH is found in the central transition (MAS), in the satellite transition (MAS and TOP) and in MQMAS experiments. For further investigations a pure aluminium hydroxide (Gibbsite) has been used. In 1H spectra under CRAMPS six lines have been observed. They could be attributed to six resolved lines in CASTEP calculations involved in intralayer or interlayer hydrogen bonds. These calculations reveal, that the aluminium surrounded by protons involved in more intralayer hydrogen bonds exhibits the larger quadrupole coupling constant.