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A short description of some of my experience in NMR.

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- 1. Ice at Room Temperature: A NMR Investigation of H 2 O in Materials under Ambient Conditions Bernie O’Hare The Pennsylvania State University
- 2. Outline <ul><li>Introduction into NMR </li></ul><ul><li>Our Hypothesis </li></ul><ul><li>Our Work </li></ul><ul><li>Introduction to Deuterium NMR (brief) and Relaxation </li></ul><ul><li>Our Results </li></ul><ul><li>Our Conclusions </li></ul>
- 3. NMR Active Nuclei
- 4. Nuclear Magnetic Resonance <ul><li>First Observed by Isidor Rabi in 1938, later refined by Felix Bloch and Edward Purcell in 1946. </li></ul><ul><li>NMR allows one to “tune in to” the desired nucleus by choosing the correct frequency (1-1000 MHz), because each nucleus has a specific Larmor frequency at a given magnetic field. </li></ul><ul><li>NMR is not a sensitive technique. NMR requires a minimum concentration of ~1mM and a minimum sample volume of ~1 ml. Because of this, we need large surface area samples to study molecules at interfaces. </li></ul><ul><li>Despite the above limitation, NMR is the one of the most powerful technique known for characterization of molecular structure and dynamics. </li></ul>
- 5. Modern NMR Spectrometer <ul><li>1 H Larmor frequency is 850 MHz </li></ul><ul><li>~ 20 Tesla Field </li></ul><ul><li>Used mainly for biological macromolecules and protein structure/function studies </li></ul>
- 6. I Had Nothing to do with the Second Quench
- 7. SEE! The Germans would have never been this happy with me.
- 8. What is NMR No External B o Field External B o Field Applied in the Z direction. B o Net Magnetization
- 9. What Can NMR do? <ul><li>Molecular structure assignments for both small molecules and proteins up to 50 kDa in size in both the liquid and solid state. </li></ul><ul><li>Dynamic studies of molecular translational diffusion. </li></ul><ul><li>Dynamic studies of rotational diffusion via NMR relaxation. </li></ul><ul><li>Dynamics of solid state motion via NMR relaxation. </li></ul><ul><li>NMR can image the body or other objects given sufficient gradients in known directions. </li></ul><ul><li>Analytical work by “spin counting” to ascertain the amount of a given nuclei in a sample </li></ul>
- 10. NMR <ul><li>Nuclear spins are aligned with or against the main magnetic field axis. </li></ul><ul><ul><li>With the magnetic field is a low energy state. </li></ul></ul><ul><ul><li>Against the magnetic field is a high energy state. </li></ul></ul><ul><ul><li>Slightly more spins are aligned with the magnetic field in the lower energy state, but not many. </li></ul></ul>Magnetic Field Increasing ******** *********
- 11. Examples of NMR
- 12. The focus of this work utilizes NMR relaxation. T 1 NMR experiment of the 2 H in 2 H 2 O 1.bp.blogspot.com/.../y1gg-u9u2rM/s400/t1.jpg
- 13. Phase Diagram of H 2 O http://www.lsbu.ac.uk/water/images/phase.gif
- 14. Materials Research with NMR
- 15. Kanemite (NaHSi 2 O 5 •3H 2 O) <ul><li>Atomic view of the kanemite crystal </li></ul><ul><li>10 Å interlayer spacings </li></ul><ul><li>Can fit 3-4 layers of molecular H 2 O </li></ul><ul><li>Naturally occurring crystal </li></ul>GARVIE ET AL.: STRUCTURE OF NaHSi2O5·3H2O, Americ. Mineral 1999.
- 16. (Na) Zeolite-A (Na 12 Al 12 Si 12 O 48 • 27H 2 O) <ul><li>Atomic view of (Na) Zeolite A </li></ul><ul><li>Supercage ~ 14 Å </li></ul><ul><li>Sodalite cages ~ 9 Å </li></ul><ul><li>About 5 layers of molecular H 2 O can fit in the supercage. </li></ul><ul><li>About 3 layers of molecular H 2 O can fit in the sodalite cages. </li></ul><ul><li>Naturally occurring zeolite crystal. </li></ul>http://www.zeolitepure.co.uk/USERIMAGES/Zeolite(1).jpg
- 17. Tricalcium Silicate Ca 3 SiO 5 (C 3 S) <ul><li>Fully hydrated C-S-H </li></ul><ul><li>Pure synthesized C 3 S crystals </li></ul>
- 18. <ul><li>1. Molecular dynamics simulations, scanning polarization force microscopy (SPFM), and sum frequency generation spectroscopy have shown the formation of room temperature “ice-like bilayers” on the surface of muscovite mica 1 , a hydrophilic aluminosilicate that can be used to “seed” clouds. </li></ul><ul><li>Room temperature solid state water is also commonly found in crystalline hydrates. 2 </li></ul><ul><li>At elevated pressure and temperatures slightly above the freezing point of pure water, solid state water is found as well in clathrate hydrates. 3 </li></ul>Previous evidence for solid state water at room temperature: <ul><li>1. (a) Hu, J; Xiao, X.-d.; Ogletree, D. F.; Salmeron, M. Surf. Sci. 1995 , 344 , 221-236. (b) Hu, J; Xiao, X.-d.; Ogletree, D. F.; Salmeron, M. Science 1995 , 268 , 267-269. (c) Odelius, M.; Bernasconi, M.; Parrinello, M. Phys. Rev. Lett. 1997 , 78 , 2855-2858. (d) Salmeron, M.; Bluhm, H. Surf. Rev. and Lett. 1999 , 6 , 1275-1281 . </li></ul><ul><li>(a) Weiss, A.; Weiden, N. In Advances in Nuclear Quadrupole Resonance, Smith, J. A. S., Ed. Heyden: 1980, Vol. 4, pp. 149-248. (b) Reeves, L. W. In Progress in NMR Spectroscopy, Emsley, J. W.; Feeney, J.; Sutcliffe, L. H. Eds. Pergamon:1969, Vol. 4, pp. 193-234. </li></ul><ul><li>(a) Bach-Verges, M.; Kitchin, S. J.; Harris, K. D. M.; Zugic, M.; Koh, C. A. J. Phys. Chem. B 2001 , 105 , 2699-2706. (b) Kirschgen, T. M.; Zeidler, M. D.; Geil, B.; Fujara, F. Phys. Chem. Chem. Phys. 2003 , 5 , 5247-5252. </li></ul>
- 19. We have used 2 H NMR techniques, isothermal calorimetry, and FT-IR to investigate water ( 2 H 2 O and 1 H 2 O) in a variety of hydrated materials: Kanemite, Zeolite A, Silicalite, Montmorillonite, Silica Gel, Porous Glass, Hydrated Tricalcium Silicate (cement), Hydroxyapatite, Cellulose, Nafion, and Sulfonimide substituted polyphosphazenes We have found room temperature solid state water in all of these samples! We have published some of the work in the papers below: A. J. Benesi, M. W. Grutzeck, B. O’Hare, and J. W. Phair, “Room Temperature Solid Surface Water with Tetrahedral Jumps of 2 H Nuclei Detected in 2 H 2 O-Hydrated Porous Silicates”, J. Phys. Chem. B , 108, 17783-17790, 2004. A. J. Benesi, M. W. Grutzeck, B. O’Hare, and J. W. Phair, “Room Temperature Ice-Like Water in Kanemite Detected by 2 H NMR T 1 Relaxation”, Langmuir , 21 , 527-529, 2005. B. O’Hare, M.W. Grutzeck, D.B. Asay, S.H. Kim, and Alan J. Benesi “Solid State Water Motions Revealed by Deuterium Relaxation in 2 H 2 O –Synthesized Kanemite and 2 H 2 O Hydrated Na + -Zeolite A”, Journal of Magnetic Resonance, 195, 85-102, 2008.
- 20. Why we use 2 H NMR? Because: We use 2 H 2 O to hydrate our samples…
- 21. 2 H NMR well suited for studying molecular motion because: Quadrupolar interaction dominates, so other interactions can be ignored. “ Rigid” qcc = e 2 qQ/h = 160-300 kHz gives rise to characteristic powder pattern in spectrum (shown below for : 3/2 qcc ¾ qcc
- 22. There is a direct link between the observed 2 H spectral frequency and the orientation of the (quadrupolar PAS) covalent bond relative to the 2 H nucleus and the applied magnetic field. Because all possible angles are found in a powdered sample, this gives rise to the powder pattern. O 2 H B 0 Because of this sensitivity to motion, 2 H NMR can be used to characterize motions with frequencies ranging from ~1 x10 -2 s -1 < < 10 15 s -1 .
- 23. Deuterium NMR and Motion <ul><li>Deuterium NMR is very sensitive to motion </li></ul><ul><ul><li>Motions << Qcc are considered rigid </li></ul></ul><ul><ul><li>Motions ~ Qcc are considered intermediate </li></ul></ul><ul><ul><li>Motions >> Qcc are considered fast </li></ul></ul><ul><ul><li>Qcc ≡ e 2 qQ/h </li></ul></ul>
- 24. Types of Motion <ul><li>Low Symmetry </li></ul><ul><li>C2 rotations </li></ul><ul><li>C3 rotations </li></ul><ul><li>Diffusion in a cone </li></ul><ul><li>Tethered motion </li></ul><ul><li>High Symmetry </li></ul><ul><li>Octahedral jumps </li></ul><ul><li>Tetrahedral jumps </li></ul>
- 25. Deuterium Motion Examples
- 26. d5- Benzoic Acid -At 22 deg C the phenyl ring flips are not apparent. -All that is observed is a static powder pattern. -Motion << Qcc
- 27. Phenyl Ring Flips (Calculated) -The deuterons undergo 180 o rotations as the phenyl ring rotates -This is a common occurrence in proteins and other large molecules with phenyl groups
- 28. d18- HMB Methyl groups experience fast 3 site jumps and produce a “mini” powder pattern as do other low symmetry fast motions. Motion >> Qcc
- 29. d4-L-Alanine (Slow Pulse) 2 types of motion 2 types of deuterons - fast 3 site jumps - slow 1 site motion Motion >> Qcc Motion << Qcc
- 30. Vertical Expansion of L-Alanine This expansions shows the static pattern more clearly Motion << Qcc
- 31. Frozen D2O The deuterons in ice slightly below its melting point exhibit highly symmetric, fast tetrahedral jumps which produce isotropic like lineshapes. Motion >~ Qcc
- 32. D 2 O ice, -120 C D 2 O ice, 0 C freezing pt. = 3.84 C, qcc D 2 O liquid, 21 C >> qcc qcc 2 H quadrupole echo spectra of 2 H 2 O (D 2 O): This is why everyone missed room temp solid state water
- 34. Earlier Models <ul><ul><li>Pure tetrahedral jumps. This model will work, but only at ONE given temperature, not very robust. </li></ul></ul><ul><ul><li>Tetrahedral jumps on an pseudo-isotropic sphere. These 2 motions were not in fast exchange, so simple addition of the spectral densities was incorrect. </li></ul></ul>
- 35. Our Relaxation Model is Simple and Robust <ul><li>( 1/T n ) Observed = X C2 (1/T n ) C2 + X tet (1/T n ) tet </li></ul><ul><li>The relaxation times are calculated using the conventions of Mehring and are based on the formalism developed by Torchia and Szabo </li></ul>The C2TET Relaxation Model
- 36. Spectral Densities Describing the Tetrahedral Relaxation
- 37. Spectral Densities Describing the C 2 Relaxation
- 38. Calculating Spectral Densities <ul><li>Using the appropriate jump matrix (i.e. C2 or tetrahedral), one can calculate the pertinent spectral densities for any type of motion </li></ul><ul><li>This is based on the formalism of Mehring but also heavily on Torchia and Szabo </li></ul>
- 39. T 1 Relaxation Model for Zeolite-A compared to experimental
- 40. Low Temperature T 1 Data
- 41. T 1 Data for kanemite
- 42. Additional Evidence
- 43. Brief Comparison of the Arrhenius versus the Eyring Plot <ul><li>They are essentially equivalent </li></ul><ul><li>The Eyring plots Δ H ‡ is the Arrhenius E a. </li></ul><ul><li>The Δ S ‡ is entropic data not available from the Arrhenius equation </li></ul>Arrhenius Equation Eyring Equation
- 44. Eyring Plots of Zeolite-A Activation parameters are determined from the dynamic lineshape simulation data Activation parameters are determined by high temperature T 1 experimental data The plot of ln k/T versus 1/T gives a straight line with slope of from which the enthalpy of activation can be derived and with intercept from which the entropy of activation is derived.
- 45. FT-IR Support
- 46. Tricalcium Silicate <ul><li>We propose the C2TET model to also exist in this system. </li></ul><ul><li>At any given time we can calculate the fraction of solid water to the fraction of “free” liquid water. </li></ul>
- 47. <ul><li>We propose that the initial strength in cement is due to the hydrogen bridges formed during the acceleratory period facilitating a phase change of bulk water to solid state water. </li></ul>
- 48. Isotope Effect on Setting of C 3 S Vicat Needle ASTM Test
- 49. Conclusions <ul><li>Deuterium NMR relaxation shows our C2TET solid state water model to be consistent and robust over a wide temperature range </li></ul><ul><li>VT- 2 H lineshape analysis is consistent with our C2TET model </li></ul><ul><li>Eyring plots show that we have activation parameter results consistent with the C2TET model </li></ul><ul><li>FT-IR gives us independent support of a solid state type of water in these materials </li></ul><ul><li>Solid state water is at least partially responsible for the initial strengthening of cement </li></ul>
- 50. NMR at Penn State
- 51. The Bruker Biospin Lloyd Jackman Highfield NMR Facility
- 52. AV-III-600
- 53. AV-III-500
- 54. High field Hardware <ul><li>All three instruments are equipped with four channels making the implementation of 2 H decoupling quite simple for biomolecules. </li></ul><ul><li>All three are equipped with the latest software, TopSpin 2.1.with patch level 4. </li></ul><ul><li>All three have the latest series cryoprobes and cryoplatforms (All CTI versions 5mm) </li></ul><ul><li>The 850 has microimaging capabilities as well as a fast MAS probe included with the CTI probe and a BCU-Xtreme for low temperature solid state NMR. </li></ul>
- 55. The Open User’s Facility
- 56. Solid State NMR <ul><li>Varian – Chemagnetics Infinity Plus 500 spectrometer equipped with four channels and a high power gradient amplifier for solid state diffusion studies. </li></ul><ul><li>There are many probes for this system including DAS and static probes. </li></ul>
- 57. Solid State NMR <ul><li>The 500 Solid State spectrometer and work station. </li></ul><ul><li>VT capabilities as well as MAS and 19 F are available and used. </li></ul><ul><li>Triple resonance experiments, i.e. trapdor, etc… are conducted routinely. </li></ul>
- 58. Solid State NMR <ul><li>Tecmag, rebuilt from Chemagnetics 300 wide bore. </li></ul><ul><li>Multitude of probes exist. </li></ul><ul><li>Most of my deuterium relaxation work was done with this system. </li></ul>
- 59. Solid State NMR <ul><li>Bruker Avance 300 wide bore </li></ul><ul><li>Equipped with a double resonance 4mm MAS probe. </li></ul><ul><li>Capable of spin rates of 15 kHz. </li></ul><ul><li>Mostly 1H-13C CP is done here. </li></ul><ul><li>Also my homonuclear dipolar suppression work. </li></ul>
- 60. Solid State NMR <ul><li>Homebuilt 400 MHz widebore system. </li></ul><ul><li>Used specifically by Dr. Karl Mueller’s group. </li></ul><ul><li>Has limited capabilities. </li></ul>
- 61. Electronics Work and Probe Repair
- 62. My Collaborative Work at PSU
- 63. OLD MEETS NEW
- 64. 13C-1H HSQC of 10% PEG <ul><li>Without BIRD filter the data is unintelligible. </li></ul><ul><li>Incorporating older NMR techniques with newer gradient selected pulse sequences gives us a great advantage when studying real samples. </li></ul>
- 65. 15N-1H HSQC No BIRD Flipped the BIRD
- 66. Stereochemical determination via 2D Homonuclear NOE Spectroscopy
- 67. Distance determination of RNA via 2D Excitation Sculpted NOE 10 o C with 30 msec mixing time 1 o C with 200 msec mixing time
- 68. Standard Small Molecule Analysis <ul><li>Adiabatic, signal enhanced HMQC </li></ul>
- 69. Ionic Liquid Diffusion NMR
- 71. Industrial NMR
- 72. Impurity Analysis 6-Hexadecenoic Acid
- 73. Small Molecule Assignments
- 74. Energetic Materials Analysis
- 75. Ubiquitin <ul><li>A small 76 amino acid protein </li></ul><ul><li>About 8.5 kDa </li></ul><ul><li>Perfect for acceptance test procedures in NMR </li></ul><ul><li>Usually doubly labeled with 15 N and 13 C isotopes </li></ul><ul><li>HSQC, TROSY-HSCQ, HNCO, HNCACO are all common experiments to verify structure via NMR </li></ul>
- 76. 15N-1H HSQC of Ubiquitin
- 77. 13C-1H HSQC of Ubiquitin
- 78. How can we deal with spectral overlap? The HNCO 3D Experiment
- 79. Ubiquitin HNCO (3D-NMR)
- 80. 3D-HNCO
- 82. TROSY-HSQC 50 kDa Protein
- 83. Solid State NMR at PSU
- 84. 1H SS MAS of Sucrose 4 kHz
- 85. Can we make that better? Spinning at 12 kHz helps a great deal, but the resolution is still poor.
- 86. My Time Averaged Magic Angle Spinning Echo Sequence
- 87. Comparison
- 88. Thank You All Very Much!

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