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核磁共振光譜與影像導論

核磁共振光譜與影像導論. Introduction to NMR Spectroscopy and Imaging Lecture 08 Introduction to Solid State NMR (Spring Term, 2011) Department of Chemistry National Sun Yat-sen University. Introduction to Solid State NMR. 8.0 Summary of internal interactions in solid state NMR

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核磁共振光譜與影像導論

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  1. 核磁共振光譜與影像導論 Introduction to NMR Spectroscopy and ImagingLecture08 Introduction to Solid State NMR(Spring Term, 2011)Department of ChemistryNational Sun Yat-sen University

  2. Introduction to Solid State NMR • 8.0 Summary of internal interactions in solid state NMR • 8.1 Typical lineshapes for static samples • 8.2 Magic-angle-spinning (MAS) • 8.3 Cross polarization (CP) and CPMAS • 8.4 Homonuclear and heteronuclear correlations (COSY/HETCOR) • 8.5 Multi-quantum MAS (MQMAS) of quadrupole spins

  3. The major interactions in solid state NMR spectroscopy.

  4. Single Crystal or Polycrystalline (Powder) Samples

  5. (Static) Powder Patterns

  6. Powder spectrum iso ,δ,

  7. B0 Magic Angle Spinning (MAS) Θ=54.74°

  8. Magic Angle Spinning (MAS) 54.74o

  9. 33 22 Z X 11 Y Coordinate Systems

  10. Magic-Angle-Spinning Spectrum

  11. MAS for spin 1/2 nuclei

  12. The Quadrupolar Majority

  13. HZ HZ + HQ HZ + HQ (powder) 2H MAS Experimental (A) and simulated (B and C) 2H MAS NMR spectra (14.1 T) of KD2PO4 using ωr= 7:0 kHz. The simulated spectrum in (B) employs the optimized 2H quadrupole coupling and CSA parameters listed below whereas the simulation in (C) only considers the quadrupole coupling interaction. The asterisk indicates the isotropic peak.

  14. Spin-3/2 23Na ( 105.8 MHz) NMR spectra of NaN03 recorded using (a) static and (b) MAS (v, = 4820 Hz) conditions ( 16 scans). The central transition is cut off at (a) 1/4 and (b) 1/13 of its total height.

  15. JORGEN SKIBSTED, NIELS CHR. NIELSEN, HENRIK BILDME, HANS J. JAKOBSEN, JMR, 95, 88(1991)

  16. Spin-5/2 27AI ( 104.2 1 MHz) MAS NMR spectra of the central and satellite transitions for α-Al2O3. The ppm scale is referenced to an external sample of 1 .0 M AlCl3, in H2O. (a) Experimental spectrum showing the relative intensities of the central and satellite transitions and observed using a Varian VXR-400 S wideline spectrometer; ωr= 7525 Hz, spectral width SW = 1 .0 MHz, pulse width pw = 1 .0 μs (π /4 solid pulse), and number of transients nt= 5 12. (b) Spectrum in (a) with the vertical scale expanded by a factor of ten; the inset shows expansion of a region where the second-order quadrupolar shift between the (±5/2, ±3/2)and the (±3/2, ±1/2)satellite transitions is clearly observed (see text). (c) Simulated MAS spectrum for the satellite transitions in (b) obtained using QCC = 2.38 MHz, η = 0.00, ωr= 7525 Hz, and Gaussian linewidths of 900 and I 175 Hz for the (±3/2, ±1/2) and (±5/2, ±3/2) transitions. respectively. HANS J. JAKOBSEN, JORGEN SKIBSTED, HENRIK BILDSBE, ANDNIELS CHR .NIELSEN,JMR 85,173(1989)

  17. 51V MAS (HQ+HCSA) Question: is it possible to suppress the sidebands of a satellite transition MAS spectrum? “Answer”: Not done yet, but it’s an interesting topic.

  18. Sensitivity • High Fields • Labeled samples • CP • CPMAS

  19. Cross Polarization • CPMAS─one of the most important solid state NMR techniques. • CP contact time: several hundred microseconds to tens of milliseconds. • Purpose: To enhance the sensitivity of the lower γ spins such as carbon-13. maximal enhancement factor: γI/γS • Other advantages: Shorter recycle delay time • Distinguish the interconnectivity of nuclear spins such as the protonation of a certain carbon nucleus.

  20. CP Pulse Sequence

  21. 1H-13C CPMAS spectrum of (a) mixed lactose, (b) -lactose and (c) anhydrous stable -lactose. The lines marked by asterisks are assigned to the residual amorphous lactose

  22. Sodium silicate glasses Static 17O NMR spectra bridging (BO) and non-bridging (NBO) oxygens Na2Si2O5 Na2Si3O7 Na2Si4O9 NBO BO 600 0 -600 ppm

  23. Structure of glasses (I) NBO BO

  24. 29Si NMR spectra for sodium silicate glasses static MAS Q4 mole % Na2O 34 37 41 Q3 Q2 Q3 + Q2 0 -100 -200 ppm -60 -80 -100

  25. Structure of glasses (II) Q4 Q2 Q3 Q1

  26. 1H-29Si CPMAS intensity as a function of contact time Q2 Q3 Q4 Different sites in a Na2Si4O9 glass with 9.1 wt% H2O 0 20 40 contact time (ms)

  27. Ramp CP(Matching Condition Satisfied at High Speeds) Acquisition X CP decoupling 1H

  28. Homonuclear correlation

  29. Homonuclear correlation : establishing connectivities

  30. Dipolar - Chemical Shift Correlation

  31. Multi-Quantum Magic-Angle Spinning (MQMAS) (for half-integr quadrupolar spins) Magic Angle (54.7 ) Spinning MQC SQC o θM θM

  32. 17O-MQMAS spectrum of the silicate coesite

  33. Applications • Polymers • Glasses • Porous materials • Liquid crystals • Biomolecules • Tissues • Soil, plants, animals, ....

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