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 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

The major interactions in solid state NMR spectroscopy.

Single Crystal or Polycrystalline (Powder) Samples

(Static) Powder Patterns

Powder spectrum iso , δ,

Magic Angle Spinning (MAS) Θ=54.74° B0

Magic Angle Spinning (MAS) 54.74o

Coordinate Systems 33 11 22 Z X Y

Magic-Angle-Spinning Spectrum

MAS for spin 1/2 nuclei

The Quadrupolar Majority

2H MAS HZ HZ + HQ HZ + HQ (powder) 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.

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.

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

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)

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.

Sensitivity High Fields Labeled samples CP CPMAS

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.

CP Pulse Sequence

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

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

Structure of glasses (I) NBO BO

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

Structure of glasses (II) Q4 Q2 Q3 Q1

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)

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

Homonuclear correlation

Homonuclear correlation : establishing connectivities

Dipolar - Chemical Shift Correlation

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

17O-MQMAS spectrum of the silicate coesite

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