Chapter 18 Introduction to Solid State NMR

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Chapter 18 Introduction to Solid State NMR Powered By Docstoc
					Chapter 18 Introduction to Solid State NMR
• 18.0 Summary of internal interactions in
  solid state NMR
• 18.1 Typical lineshapes for static samples
• 18.2 Magic-angle-spinning (MAS)
• 18.3 Cross polarization (CP) and CPMAS
• 18.4 Homonuclear decoupling pulse
  sequences
• 18.5 Recoupling (CSA and dipolar)
• 18.6 Multi-quantum MAS (MQMAS) of
  quadrupole spins
• 18.7 Applications
• High resolution solid state NMR
• Recoupling (Secoupling)
• Resolution gap between LSNMR and
  SSNMR: still large but decreasing
• “Solid NMR” in chemistry and condensed
  matter physics can be very different (the
  later normally uses conducting samples
  that contain large Knight shift)
Single Crystal or Polycrystalline (Powder)
                 Samples
Review of Lecture 9 for the summary of the four
major interactions in NMR spectroscopy.
Magic Angle Spinning (MAS)
                                  Θ=54.74°
                             B0
Coordinate Systems



                     (0,  RL  M ,r t )
                      
              LF 

                  ( ,  , )
                  
            RF 

            ( , , )
        MF  PAS  
                   Coordinate Systems




                                                     (0,RL M ,r t )
                                 LF( X L ,YL , ZL )             

                                                            ( , , )
                                                         
                                   RF( X R ,YR , ZR ) 
    33
              22
                           MF( X ,Y , Z ) ( , , ) PAS(11,22,33)
                                                   
X                      Z


         11
              Y
                                              Coordinate Systems                                                                                  33



    , , )
 (                                                                                                                                             22
                                                                                                                                         β   11
Molecular frame (may be a PAS of
certain interaction tensor)
    ( ,  , )
          




      Lab Frame(XYZ)
                                2           k
                                                                     
  H   R                                               k , m'T k , m                              C, D, Q, J
                        k
                             k  0 m  k
 R k ,m             
                  m ', m " k
                                 (1)m D( k ) m ",m ' (0,M , r t ) D( k )m ', m ( ,  ,  )   k ,m '
              k
 or         
      m ', m ", m ''' k
                            (1)m D( k ) m '",m '' (0, M , r t ) D( k ) m '', m ' ( ,  ,  ) D( k ) m ', m ( , , )   k ,m '
                         How to calculate a solid NMR spectrum

         2       k
  
H    R k , m'T  k , m                  C, D, Q, J
        k  0 m  k



                  ( ,  ,  , ,  , )
                          
        S ( )             sin  d d  d e
                                                                    i ( ,  , , , , ) t it
                                                                                                   e dt
                              
                           , ,



More generally,


                     
                                                       iH  ( ,  , , , , ) t            iH  ( ,  , , , , ) t
      S ( ) 
                 
                      sin  d d  d [ I e
                         , ,
                                                                                       (0)e                                 ]eit dt
            Sensitivity


•   High Fields
•   Labeled samples
•   CP
•   CPMAS
                     Cross polarization
•    CPMAS─one of the most important
  solid state NMR techniques.
                        1, I 1, S
• 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.
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


                                           Na2Si2O5

bridging (BO) and
non-bridging (NBO)
oxygens                                    Na2Si3O7
                     NBO
                               BO
                                           Na2Si4O9
             600           0        -600      ppm
Structure of glasses (I)

                   O         O
                       Si
               O
      O                          Na
                   O        O              O
          Si
                       Si
      O                         O       Si     O
               O
O
     Si                 Na          O
               Si
          O
 O                     O
                                      Na
                                                    NBO
     Si        O
          Na            Si
                   O             O
                       O                           BO
29Si   NMR spectra for sodium silicate glasses


                   static             MAS
           Q4

                            mole %
                             Na2O

                              34
                                                Q3
                              37           Q2
         Q3 + Q2              41

 0        -100        -200 ppm       -60        -80   -100
Structure of glasses (II)

                        O           O
                              Si
           O
                    O                               Q4
                        O          O
               Si                                   Q2
                              Si
           O                           O
                    O
 O
       Si                    HO         Si
                        Si                      O
               O
 HO                           O HO
                   HO
                               Si
                    HO                  OH
                             HO

      Q3                                   Q1
1H-29Si CPMAS
intensity as a                                    Q2
function of contact
time
                                                  Q3
Different sites in a Na2Si4O9
glass with 9.1 wt% H2O


                                                  Q4



                                0         20          40
                                    contact time (ms)
                Ramp CP
(Matching Condition Satisfied at High Speeds)
                             Acquisition

   X


        
        2
               CP           decoupling


   1H
        Comparison of standard and ramp-CP
Carbonyl-signal of glycine (nat. abundance), nrot = 20 kHz,
as function of 1H-power
                                                        rectangle



                                    1I=1S  nR
                                                        ramp




   10    11   12   13   14    15   16    17   18   19      pl2 in dB
                Double-CP
     
     2
         CP 1               Decoupling

                Avoid CP

1H


                 CP 2

Y


                              Acquisition
X
                                                                   H-N-C Double- CPMAS:
                                                                   Spectral Simplification




(A) CP-MAS 13C NMR spectrum and (B) 15N-13C double-
CP/MAS NMR data of the [13C6,15N3]-His labeled LH2 complex,
measured at 220 K by using a wide-bore 750 NMR spectrometer. The
spinning rate around the magic angle was kept at 12 kHz. Each spectrum
represents about 156 000 scans collected with an acquisition time of 8
ms and a recycle time of 2 s. The spectra are normalized at the α’ peaks.



      de Groot et al., JACS 123,4203(2001).
                       Shielding
           B0


                                                  Bi
                               i
                                    i

electronic shielding         induced magnetic field


        Bloc = B0 – Bi = B0 (1 – s)
             Shielding Tensor: Decomposed
                           1                    1
            s xx               ( s xy  s yx )      (s xz  s zx )
                           2                    2               ÷
        1                                         1
  s 
   s   ( s  s )                 s yy             (s yz  s zy )÷
        2 xy
       1
                 yx
                                                  2
       (s  s )            1                                    ÷
                                                                  ÷
                               (s yz  s zy )          s zz
       2 xz    zx
                             2                                    
                            1                    1
                0               (s xy  s yx )       (s xz  s zx )
                            2                    2               ÷
           1                                       1
  s as   (s yx  s xy )          0                (s yz  s zy )|
           2                                       2
         1
          ( s  s )         1                                    ÷
                                ( s zy  s yz )         0          |
         2 zx       xz
                              2                                    

Theoretically, CSA tensor contains anti-symmetric components, but the
experimental evidence has been rather weak. It remains an interesting
topic in fundamental NMR research.
(Static) Powder Patterns
                          Powder spectrum

       CH3                 O
       C        O          S      O
       CH3                 O          x




                           0 3cos 2   1   sin 2  cos 2
                           1
cs ( ,  )  0s iso
                           2

                 siso , δ,
Magic-Angle-Spinning Spectrum
MAS for
spin 1/2 nuclei
Total Suppression of Spinning Side Bands (TOSS)
TOSS Example
                            TOSS Example




Proton NMR spectra of a water and hexadecane mixture in a sample of packed glass beads.
The Quadrupolar Majority
First and Second Order Quadrupolar Hamiltonains
         H  H B  H CSA  H D  H J  H Q  H rf
    H B  S Z                                          H rf  1S

     HQ            ( 0)
                   HQ                   (1)
                                        HQ

      HQ 
       (0)            2
                      3   V20 [3S Z  S ( S  1)]
                            Q     2


      H Q   2L S Z [(4S 2  8S Z  1)V21V21 
        (1)                       2       Q Q


      (2 S 2  2 S Z  1)V22V22 ]
                   2       Q Q

                  2
      V2Qj     
               m , n 2
                            Dmj (R t ,  M , 0) Dnm ( ,  , )  2 n , j  0, 1, 2
                             2                    2                Q




        6Q  6
       Q
       20
                                        e2 qQ
                                    8 I (2 I 1)   ,  22   2  2   Q Q
                                                       Q      Q
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.
Half-Integer Quadrupolar Spins:
        Central Transtion




                  HQ 
                   (0)      2
                            3   V20 [3S Z  S ( S  1)]
                                  Q     2


                  H Q   2L S Z [(4 S 2  8S Z  1)V21 V21 
                    (1)                        2       Q Q


                 2 S 2  2 S Z  1)V22 V22 ]
                             2       Q Q




                     A few hundred Hz to several kHz
Satellite Transitions
             HQ 
              (0)       2
                        3   V20 [3S Z  S ( S  1)]
                              Q     2


             H Q   2L S Z [(4 S 2  8S Z  1)V21 V21 
               (1)                        2       Q Q


             2 S 2  2 S Z  1)V22 V22 ]
                         2       Q Q




              Static




              MAS




                Hundreds kHz to a few MHz!
                  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. 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.
Direct Dipole-Dipole Coupling
Direct Dipole-Dipole Coupling
                  Dipolar Coupling




       0  h  i  j
dij              3
        4 2 r
Direct Dipole-Dipole Coupling




                          ~80 kHz




                      Many coupled spins
 Spin Pair
Homogeneous Interaction (Homonuclear Dipolar Interaction):
         All Spins Are Coupled to Each Other
                 0      i j
                        2
    H D,ij                     [3(Ii                )(I j                )  Ii  I j ]
                                            ri , j                ri , j
                 4     rij3               |ri , j |             |ri , j |
                  2
   HD           (1)m D(2) 0, m (ij ,ij , 0)  D,ij 2,0T D,ij 2,m
          i j   m2
                                                                               0                i
                                                 
                                                                                                          2
                                                        D ,ij
                                                        2,0                  4          6          j
                                                                                                      3
                                                                                                    rij

                                                  2, ij  0   2, ij
                                                   D,
                                                        1
                                                                  D,
                                                                       2



                                                   T2,0,ij 
                                                     D             1
                                                                    6
                                                                         (3I i , z I j , z  I i  I j )
                                                   T2, ,1 
                                                     D ij               1
                                                                        2    ( I i , I j , z  I i , z I j , )
                                                   T2, ,2 
                                                     D ij        1
                                                                 2    I i, I j ,
              Decoupling Sequences
• Hetronuclear decoupling:
   CW
   TPPM
   XiX
   COMORO
   SPINAL
   SDROOPY,eDROOPY,DUMBO, eDUMBO, eDUMBO lk
• Homonuclear decoupling
    WAHUHA
    Lee-Goldburg (LG and variants: FSLG, PMLG,wPMLG)
    MREV-8
    BR-24
    BLEW-12
    CORY-24
    TREV-8
    MSHOT-3
    DUMBO, eDUMBO, eDUMBOlk,
    CNnv, RNnv
           Decoupling sequences: TPPM
TPPM = Two Pulse Phase Modulation

              
         p 0    p      p 0    p 




Pulse length: p   - e: e  0 – 0.6 s, optimize!
Phaseshift:   15°, evt. optimize!
        TPPM- decoupling, optimize tp
C-signal in Glycine-2-13C-15N, nrot= 30 kHz,  = 15°

                                      ndec = 150 kHz




  2.0
         2.5     3.0
                        3.5
                                4.0
                                        4.5   p/s

 optimum pulse length: p = 2.9 s, (3.2s)
                      XiX - decoupling
XiX= X Inverse X

    
      p 0       
                  p 180
                             
                              p 0        
                                          p 180




     n R                                         t
Pulse length: p = x ·R, x  n, but x  n, ...
(recoupling at (n/4)R )         optimize!
                 XiX- decoupling, optimize p
C-signal of glycine-2-13C-15N, nrot= 30 kHz,
      3              3 R          1             1
     2 R                         3 R          3 R
      4                            4             2
                                                       ndec = 150 kHz




                                                             p/s
90          95      100     105     110   115          120
         Comparison of decoupling methods
C-signal of glycine-2-13C-15N, ndec = 150 kHz

10 kHz




          TPPM (15°)        CW                   XiX


30 kHz
    Decoupling methods: π-pulse decoupling
Rotorsynchronised train of 180°-pulses
xy-16-phase cycle for large band width
 0  90  90  0  0  90  90



   R                                                      t
 xy-16-phase cycle: 0–90–90–0–0–90–90–0–180–270–270–180–
 180–270–270–180
                   π-pulse decoupling for 19F
19F:Dipol-Dipol-coupling spun out at fast rotation
     but: large chemical shift anisotropy
 large band width important


                                               19F-spectrum  of
                                               teflon at 30 kHz




       1000        0            Hz




       4e+04           2e+04     0e+00       -2e+04           Hz
               π-pulse-decoupling for 19F
13C{19F}-CP/MAS-spectrum       of Teflon, nrot= 30 kHz



             CW                      TPPM 15°                  -pulse




 140   120   100   ppm   140   120   100   ppm   140     120   100   ppm
   Pulsed (homonuclear) decoupling

  WAHUHA
  Lee-Goldburg (LG and variants: FSLG, PMLG,
wPMLG)
  MREV-8
  BR-24
  BLEW-12
  CORY-24
  TREV-8
  MSHOT-3
  DUMBO, eDUMBO, eDUMBOlk,
  CNnv, RNnv
         Lee-Goldburg (LG) Series
LG: Magic-angle-spinning in spin space (Magic Sandwich)

                                                          Z    54.74o



         [ *]             n
                                                     Δω
                                                                        Y


                                                 X
                                                              ωrf


        [ *]             n
                                      rf  1 cos(t p  )


                    Frequency-Switched LG     (windowed) Phase-Modulated LG
       TREV-8

[ *]
   n
               MSHOT
(Magic Sandwich High Order Terms Decoupling)
          MSHOT
                         M. Hohwy and N. C. Nielsen, J. Chem. Phys. 106, 7571 (1997).
                         M. Hohwy, P. V. Bower, H. J. Jakobsen, and N. C. Nielsen, Chem,
                         Phys. Lett. 273, 297 (1997)
                         M. Hohwy, J. T. Rasmussen, P. V. Bower, H. J. Jakobsen, and N. C. Nielsen
                         J. Magn. Reson. 133,374(1998).




Ca(OH)2   Malonic Acid                        KHSO4
MSHOT-3-CRAMPS (combination of rotation and multi-
            pulse spectroscopy
PMLG, wPMLG
wPMLG: Example




     The one-dimensional proton spectra of (a) U–15N–DL-alanine, (b) monoethyl fumarate,
     (c) glycine and (d) U–13C –15N–histidineHClH2O, detected during wPMLG-5 at a
     spinning frequency of 14.3 kHz and a Larmor frequency of 300 MHz. The length of the
     detection windows was 3.2μs and that of the PMLG pulses was 1.7 μs.
2D proton–proton correlation spectra of U–13C–histidineHClH2O, obtained using the pulse sequence shown at the top,
with mixing times of (a) 200 μs and (b) 500 μs. The F1 (vertical) and F2 (horizontal) proton spectra are skyline projections of the 2D
spectra. These experiments were performed at a spinning frequency of 14.286 kHz and a Larmor frequency of 300 MHz. During the
PMLG-9 and wPMLG-5 irradiation the pulse lengths were 1.1 and 1.7 μs, respectively. The length of the detection windows during
wPMLG-5 was 3.2 μs.
2D carbon–proton correlation spectra of U–13C–histidineHClH2O, obtained using the pulse sequence shown at the top,
with Lee–Goldburg CP mixing times of (a) 80 μs and (b) 3 ms. The F1 (vertical) carbon and F2 (horizontal) proton spectra are skyline
projections of the 2D spectra. These experiments were performed at a spinning frequency of 14.286 kHz and a Larmor frequency of
300 MHz. During the wPMLG-5 irradiation the pulse lengths were 1.7 μs and the length of the detection windows was 5.1 μs.
FSLG for Heteronuclear Decoupling




    CH2
                 CH
           Pulsed (homonuclear) decoupling
           (WAHUHA (WHH4), MREV-8)


                                                                                               [ *]  n

J. S. WAUGH, L. HUBER, AND U. HAEBERLEN, Phys. Rev. Lett. 20, 180 (1968).




   P. MANSFIELD, M. J. ORCHARD, D. C. STALKER, AND K. H. B. RICHARDS, Phys. Rev. B 7, 90 (1973).
   W. K. RHIM, D. D. ELLEMAN, AND R. W. VAUGHAN, .I. Chem. Phys. 59, 3740 (1973).
   W. K. RHIM, D. D. ELLEMAN, L. B. SCHREIBER, AND R. W. VAUGHAN, J. Chem. Phys. 60, 4595 ( 1974).
                            BR-(24,48,52)


        [ *]                 n




D. P. BURUM AND W. K. RHIM, J. Chem. Phys. 71, 944 (1979).
                          BLEW-(12,48)

        [ *]                n




D. P. BURUM,* M. LINDER, AND R. R. ERNST, J. MAGN. RESON. 4, 173-188 (1981)
       CORY-24

[ *]
   n
eDUMBO (experimental Decoupling
Using Mind-Boggling Optimization)




   Hrf =ω1[Ixcosψ(t)+Iysinψ(t)]




               MAS rate = 22 kHz
             DUMBO and eDUMBO




Flow diagrams illustrating (a) the DUMBO and (b) the eDUMBO approaches to developing
improved decoupling schemes.
Symmetry Based Decoupling Pulse Sequences



                                   [ *]     n
    Indirect Spin-Spin Coupling
•
         Dipolar-Chemical Shift NMR (1D)
• The interplay of chemical
  shift anisotropy and spin-spin
  coupling interactions results
  in complex line shapes.
• The dipolar-chemical shift
  method is useful in the case
  of isolated spin pairs.




      Many other cases where more than one interaction are involved.
Multidimensional Approaches


• Separation of Local Fields (Correlation)
• MQC-SQC Correlation
                  Separation of Local Fields
Chemical shift correlation



Chemical shift -dipolar correlation




 Chemical shift-quadrupolar correlation

                             Interaction A            Interactions B(+A)
                                             Mixing
              I                    t1          tm          t2


              S
Homonuclear correlation :
establishing connectivities
Dipolar - Chemical Shift Correlation
                  Dipolar Coupling




       0  h  i  j
dij              3
        4 2 r
Measuring dipolar coupling constants
Homonuclear correlation between I = 1/2
               spins
Double/single quantum correlation
Homonuclear double/single-quantum
           correlation



    OH    O       H       OH
C             C   C   C
    O    HO       H       O
                                                MQMAS
H  H B  H CSA  H D  H J  H Q  H rf
H B  S Z                                                          H rf  1S

     HQ                     ( 0)
                            HQ                        (1)
                                                      HQ
  H Q0) 
    (                2 Q
                     3
                              2
                       V20[3S Z    S ( S  1)]
  H Q1)   2 S Z [(4S 2  8S Z  1)V21V21 
    (                          2       Q Q
                      L

  2S 2  2S Z  1)V22V22 ]
            2       Q Q

                 2
  V2Qj                  Dmj ( Rt , M ,0) Dnm ( , , )  2 n , j  0,1,2
                           2                  2               Q
             m , n  2

                                      e 2 qQ
   20
    Q
          6Q  6                8 I ( 2 I 1) 
                                                    ,  22   2  2   QQ
                                                        Q      Q
Under rapid magic angle spinning (MAS):

                                Q 2
                    I I     L
                                       [ A0C0 ( I )  A2 ( ,  )C2 ( I ) P2 (cos M )
                                            S                     S


                      A4 ( ,  )C4 ( I ) P4 (cos M )]
                                   S
Lineshape of half-integer quadropolar nuclei

  static                             MAS
Quadrupolar CouplingDig EFGs From This
May Be Very Strong!      Spectrum!                             Multiple Sites




             m
            3/2

                                                                   In A Powder
            1/2

           -1/2


           -3/2
                  Zeeman        Quadrupolar       Quadrupolar
                                (first-order)     (second-order)
Energy Levels of a Spin-3/2 Nucleus in a Static Magnetic Filed
    Second Order Quadrupolar Frequency

               Q 2
   I I     L     [ A0C0 ( I )  A2 ( ,  )C2 ( I ) P2 (cos )
                           S                     S


    A4 ( ,  )C4 ( I ) P4 (cos )]
                 S



   2D Solution:Keep AND Remove
                                                P2 (cos 54 .74 o )  0
  [C2S ( I1 ) P2 (cos M )t1  C2S ( I 2 ) P2 (cos M )t2 ,
  C ( I1 ) P4 (cos M )t1  C ( I 2 ) P4 (cos M )t2 ]  [0,0]
    S
    4
                                  S
                                  4


                                          t1 / t2  C4S ( I 2 )C4S ( I1 )
Both The EFG Information And High
 Resolution Can Be Achieved.
Multi-Quantum Magic-Angle Spinning (MQMAS)




          MQC        SQC       Magic Angle




                                    o
                               (54.7 ) Spinning

                θM                  θM
Multiple quantum selection : phase cycles

                              (i) direct method
                              (ii) indirect method
L.Frydman, J.S.Harwood, JACS, 1995.
17O-MQMAS   spectrum of the silicate coesite
MQMAS Signal Enhancement



RIACT
QCPMG
Shaped Pulses
FASTER
SPAM + STMAS
…
What MQMAS Tells And Does Not
           Tell
  Three Principal Values—Yes! Plus Isotropic
    Chemical Shift                          Z
Orientation—No For Powder Samples Used

                    V11

              V22                        V33


                                               Y
                                 X
              What MQMAS May Tell
         The Relative Orientation Between Two
        Quadrupolar Tensors
        ZA      V33,A                       ZB
                         V11,B
  V11,A
                    YA                    V33,B
V22,A
                         V22,B
                                                  YB
                        XA           XB
Relative Orientation Is The Same
 For All Crystallites In A Powder
 Sample
              EFG Tensor of Spin A

              EFG Tensor of Spin B
MQMAS Spin Diffusion/Exchange Pulse
Sequence


      P1      t1       P2 tm P3    t2




    MQC of Spin A(B)       SQC of Spin B(A)




           A(3/2,-3/2)B(1/2,-1/2) Scheme
  Two Spin-3/2 MQMAS-Spin Diffusion Spectrum
                           C q ,1  2.5MHz ,1  0.5,
                           C q , 2  1.4 MHz , 2  0.1.
                           (  ,  ,  )  (90 o ,0 o ,45 0 )




                         (3/2,-3/2)(1/2,-1/2)




                                                  Ding Lab


Cross Peaks               MQMAS Peaks
Ding Lab
3D CSA-D Correlation (with One Quadrupolar Spin)




                         Six nonequivalent Na sites are resolved.




                         J. Grinshtein, C. V. Grant, L. Frydman,
                         J Am Chem Soc 124,13344(2002).
              Recoupling
• High resolution achieved with MAS
  sacrifices information on anisotropy.
• Anisotropy can be recovered with
  recoupling
• Selective and broadband recoupling
• CSA recoupling and dipolar recoupling
          CSA Recoupling
• Off magic angle spinning
• Stop and go (STAG)
• Magic-angle-hopping (MAH)
• Switching-angle-spinning (SAS) or
  Dynamic-angle-spinning (DAS)
• Magic-angle-turning (MAT)
• (SPEED)
        Dipolar Recoupling
•   SEDOR
•   REDOR
•   DRAMA
•   (DRAW)
•   TRAPDOR
•   REAPDOR
•   C7
Dipolar recovery at the magic angle
             (DRAMA)
Full DRAMA sequence
Zero and double quantum coherence
Double quantum filtered experiments
The C7 recoupling sequence
Rotational resonance experiment
Data resulting from rotational resonance
 Heteronuclear correlation :
general spin-echo sequence
Spin-echo double resonance experiment
              (SEDOR)
The REDOR experiment
Transfer of population in double resonance
               (TRAPDOR )
Adiabatic zero crossing




                               12
                          
                              R
REAPDOR sequence for measuring dipolar
 couplings between I ≥ 1 and I = 1/2 spins
Example of relaxation: dipolar relaxation
How does the magnetization relax back to equilibrium after applying a
radiofrequency pulse?
How does the spectra density J depend on the correlation
time?
•




In the extreme narrowing limit (very fast motion and very short correlation time), the following holds.
•
                 Other Topics
•Multiple pulse for homonuclear decoupling (WAHUHA,
 MREV, HR, CORY etc)
•Combination of rotation and multiple pulses (CRAMP)
•Recoupling (Rotational Resonance, REDOR, RFDR etc)
•Other multi-dimensional solid state NMR (HETCOR,
 CSA/Q correlation, D/Q correlation, 3D correlation
 spectra)
•Single-Crystal NMR
               Applications
•   Polymers
•   Glasses
•   Porous materials
•   Liquid crystals
Schematic of a typical semicrystalline linear
                 polymer
Stereochemical issue in substituted
           polymers
          H   H



                  linear polyethylene




                  isotactic polypropylene




                  syndiotactic polypropylene




                  atactic polypropylene
Signature of stereoregularity in the solid state
                  spectrum
Static 2D exchange spectrum for
    polyethyleneoxide (PEO)




Experiment         Simulation
3D static 13C exchange spectra of
polyethyleneoxide polyvinylacetate
               Applications
•   Polymers
•   Glasses
•   Porous materials
•   Liquid crystals
Static whole-echo 207Pb NMR spectra
        in Pb-silicate glasses


                                mol %
                                PbO
                                66
                                50.5
                                31


                   Linewidth ~400 kHz @ 9.4 T
                   —> signals of 6 experiments summed up


      4000   0    -4000       ppm
           Sodium silicate glasses


Static 17O NMR spectra


                                           Na2Si2O5

bridging (BO) and
non-bridging (NBO)
oxygens                                    Na2Si3O7
                     NBO
                               BO
                                           Na2Si4O9
             600           0        -600      ppm
Structure of glasses (I)

                   O         O
                       Si
               O
      O                          Na
                   O        O              O
          Si
                       Si
      O                         O       Si     O
               O
O
     Si                 Na          O
               Si
          O
 O                     O
                                      Na
                                                    NBO
     Si        O
          Na            Si
                   O             O
                       O                           BO
29Si   NMR spectra for sodium silicate glasses


                   static             MAS
           Q4

                            mole %
                             Na2O

                              34
                                                Q3
                              37           Q2
         Q3 + Q2              41

 0        -100        -200 ppm       -60        -80   -100
Structure of glasses (II)

                        O           O
                              Si
           O
                    O                               Q4
                        O          O
               Si                                   Q2
                              Si
           O                           O
                    O
 O
       Si                    HO         Si
                        Si                      O
               O
 HO                           O HO
                   HO
                               Si
                    HO                  OH
                             HO

      Q3                                   Q1
1H-29Si CPMAS
intensity as a                                    Q2
function of contact
time
                                                  Q3
Different sites in a Na2Si4O9
glass with 9.1 wt% H2O


                                                  Q4



                                0         20          40
                                    contact time (ms)
           Efficiency for (1H 29Si)-CP
                               Acquisition

29Si




       
       2
                 CP            decoupling


1H


                   
29Si   MAS NMR spectra for a CaSi2O5 glass



   x8         SiO4   SiO5    SiO6
                                      quenched from a
                                      10 GPa pressure melt
   glass                              isotopically enriched



                                      high pressure phase
   crystal                            normal isotopes

        -50   -100    -150   -200   ppm
11B   MAS NMR spectra for a sodium borate
                 glass
                                (with 5 mole% Na2O)


           data                       slow cooled
           fit     R            BO4
                       NR
          30      15        0     ppm




           data                       fast cooled
                   R
           fit                  BO4
                       NR
31P   MAS NMR spectra for sodium phosphate
                 glasses
      mol % Na2O    Q1       Q2
          56

          53

          40

          30

          15
                                  Q3
          5
              100        0         -100   ppm
31P   double-quantum NMR spectrum

             Q1              Q2




                                          Double-quantum dimension (ppm)
                                    -60

             1-2              2-2

                           2-1
                   1-1
                                    0
                  0            -30
            Single-quantum dimension
1H   MAS NMR spectrum for a GeO2-doped
              silica glass

 loaded with H2
 and UV-irradiated                  SiOH + GeOH
 after subtraction        GeH
 of intense back-
 ground signal                         9.4 T, 10 kHz spinning

                     12         6       0         -6 ppm

Sample contains ~8 ´1019 H atoms/cm3
(corresponding to about 500 ppm of H2O)
17O 3QMAS NMR spectrum for a glass on
  the NaAlO2-SiO2 join with Si/Al = 0.7


                        -50
  MAS dimension (ppm)




                          0

                                  Al-O-Al
                         50
                                             Si-O-Al

                        100
                              0    -10 -20 -30 -40 -50
                                  Isotropic dimension (ppm)
 17O                   3QMAS NMR spectrum for a
                           borosilicate
                      -100
MAS dimension (ppm)

                       -50                       B-O-B


                        0

                             Si-O-Si
                       50
                                       Si-O-B

                      100
                              -25      -50      -75     -100
                                Isotropic dimension (ppm)
11B-{27Al}     CP-HETCOR NMR spectrum


                      BO3   BO4

                                            -80



        AlO6                                0
  AlO5
     AlO4
                                            80

   40            20         0     -20 ppm
               Applications
•   Polymers
•   Glasses
•   Porous materials
•   Liquid crystals
           Porous materials




Sodalite                  Zeolite A
            Porous materials




Faujasite                 Cancrinite
          Porous materials




Zeolite ZK-5                 Zeolite Rho
         Zeolite framework projections




  AlPO4-5          AlPO4-11           VPI-5
along [001]       along [100]      along [001]
                                                            2
High-resolution  29Si
                  MAS                                   3
                                   (Si/Al) = 1.03               1
                                                    4                   2.00
                                                                    0
NMR spectra of synthetic
Na-X and Na-Y zeolites                       1.19
                                                                        2.35

                               4
        Si(nAl) lines   n=         3
                                             1.35
                                       2
                                           1 0
                                                                        2.56

                                             1.59


                                                                        2.61
                                             1.67



                                             1.87                       2.75



                             -80 -90 -100 -110      -80 -90 -100 -110
Possible ordering
schemes for zeolite
Y
Si/Al = 1.67
Intensity ratios:
Si(4Al):Si(3Al):Si(2Al):Si(1Al):Si(0Al)


                                          Si

                                  Al
                                               3
                                    2
29Si MAS NMR                             1
spectrum of highly
siliceous mordenite

                                    Intensities




                      -110   -112       -114   -116   -118 ppm
         Mordenite structure along [001]




T-site     No. per unit cell   Neighbouring sites   Mean T-O-T bond angle

T1                    16       T1, T1, T2, T3                150.4°
T2                    16       T1, T2, T2, T4                158.1°
T3                    8        T1, T1, T3, T4                153.9°
T4                    8        T2, T2, T3, T4                152.3°
         Mordenite structure along [001]




                                                T1/T3/T2+T4 : 3 cross peaks
                                                T1/T4/T2+T3 : 2 cross peaks
                                                T2/T3/T1+T4 : 2 cross peaks
                                                T2/T4/T1+T3 : 3 cross peaks

T-site     No. per unit cell   Neighbouring sites   Mean T-O-T bond angle

T1                    16       T1, T1, T2, T3                150.4°
T2                    16       T1, T2, T2, T4                158.1°
T3                    8        T1, T1, T3, T4                153.9°
T4                    8        T2, T2, T3, T4                152.3°
                                        T1          T2 + T4
29Si MAS NMR                                 T3
spectrum of highly
siliceous mordenite

 J-scaled COSY spectrum


T1/T3/T2+T4 : 3 cross peaks
T1/T4/T2+T3 : 2 cross peaks
T2/T3/T1+T4 : 2 cross peaks
T2/T4/T1+T3 : 3 cross peaks


                              -110   -112    -114    -116     -118 ppm
29Si   MAS NMR spectra of ultrastabilized and
       hydrothermally realuminated zeolites
                                             2
                                                   1

                                         3
                                                           Si/Al = 2.56
                                                       0



        4.96                      4.26                         7.98




        2.44                      2.70                         2.09



  -80    -90   -100 -110   -120     -90          -100 -110 -120   -90   -100   -110 ppm
       Chemical reactions in zeolites

            1000 °C
{C} + H2O             CO + H2   (water gas reaction)
        Chemical reactions in zeolites

             1000 °C
{C} + H2O              CO + H2     (water gas reaction)

……. + x O2             (n-x) CO + n H2 + x CO2    (water gas shift)
        Chemical reactions in zeolites

             1000 °C
{C} + H2O               CO + H2     (water gas reaction)

……. + x O2              (n-x) CO + n H2 + x CO2    (water gas shift)
             catalyst
CO + 2 H2               CH3OH       (conversion of synthesis gas)
        Chemical reactions in zeolites

             1000 °C
{C} + H2O               CO + H2     (water gas reaction)

……. + x O2              (n-x) CO + n H2 + x CO2    (water gas shift)
             catalyst
CO + 2 H2               CH3OH       (conversion of synthesis gas)
             Zeolites
CH3OH        150 °C     CH3OH + CH3OCH3
        Chemical reactions in zeolites

             1000 °C
{C} + H2O               CO + H2      (water gas reaction)

……. + x O2              (n-x) CO + n H2 + x CO2     (water gas shift)
             catalyst
CO + 2 H2               CH3OH        (conversion of synthesis gas)
             Zeolites
CH3OH        150 °C     CH3OH + CH3OCH3

             Zeolites
……..         300 °C     complex mixture of hydrocarbons
        Chemical reactions in zeolites

             1000 °C
{C} + H2O               CO + H2      (water gas reaction)

……. + x O2              (n-x) CO + n H2 + x CO2     (water gas shift)
             catalyst
CO + 2 H2               CH3OH        (conversion of synthesis gas)
             Zeolites
CH3OH        150 °C     CH3OH + CH3OCH3

             Zeolites
……..         300 °C     complex mixture of hydrocarbons
 13C  MAS NMR spectrum of H-ZSM-5 with 50
torr of adsorbed MeOH heated to 300 °C for 35
                    mins




                           0   -5   -10    -15




       40   30   20   10       0          -10 ppm
 13C  MAS NMR spectrum of H-ZSM-5 with 50
torr of adsorbed MeOH heated to 300 °C for 35
                    mins


                                                    scalar coupling


                           0   -5   -10    -15               C     H



                                                       1J        = 125 Hz
                                                            CH

                                                    a quintet with ratio
                                                    1:4:6:4:1 is expected
                                                    for methane

       40   30   20   10       0          -10 ppm
Heteronuclear 2D J-resolved 13C MAS NMR
                spectrum




                                                 300
                                                 200
                                                 100
                                                 0 Hz
                                                 -100
                                                 -200
                                                 -300



 26   24   22    18   17   16   15   -11   -12 ppm
13CNMR spin diffusion spectrum of products
of methanol conversion over zeolite ZSM-5




                     25   20   15   10 ppm
 13C  MAS NMR spectrum of H-ZSM-5 with 50
torr of adsorbed MeOH heated to 300 °C for 35
                    mins
                                                    Methane
                                                    Ethane
                                                    Propane
                                                    Cyclopropane
                                                    n-Butane
                           0   -5   -10    -15      Isobutane
                                                    (n-Pentane)
                                                    Isopentane
                                                    n-Hexane
                                                    n-Heptane




       40   30   20   10       0          -10 ppm
                   Methylated aromatic products

                                                                         CH 3

                                                                                 CH3
                            CH 3             CH3
                                                                                       CH3           CH 3         CH3
                                                     CH 3
                                                                   H3C                        CH 3
                                                                         CH 3
               H3C                  CH3
                                                                                                                          CH 3
                            CH 3             CH3
             CH3              CH3                                                                    CH 3
                                                   CH3
                                      CH 3                  CH 3

                                                                                                                   CH 3
      H3 C           CH 3             CH 3                  CH 3
                                                                                             *
                                                   CH3


                   CO                                                *                           *    *            *




190           185                   180                            140          135          130            125      ppm
129Xe   NMR as a sensitive tool for materials


              0   S   Xe  Xe  Xe   E  M 

                0:      reference
                S:      surface collisions
                Xe:     Xe-Xe collisions
                E:      electric field effect
                M:      paramagnetic species
              129Xe   as a sensitive probe for various
                              zeolites


                                                 ZK4
                                                          ZSM-5
   1021
                                 NaY                     ZSM-11
Xe atoms /g




                                                       K-L


                                                 omega
   1020

                  60        80     100     120         140 ppm
               Applications
•   Polymers
•   Glasses
•   Porous materials
•   Liquid crystals
    Graphitic nanowires




Hexa-peri-hexabenzocoronene (HBC)
HBC monolayer on HOPG
Phase transitions of alkyl substituted HBC
Temperature dependence of the one
 dimensional charge carrier mobility
Liquid crystalline (dichotic) behaviour of
         alkyl substituted HBC‘s




R = C12H25
Hexadodecyl-hexa-peri-hexabenzocoronene (HBC-C12)
Charge carrier mobility in HHTT       S
                                          S

                                  S

                                  S

                                          S
                                      S
1H   DQ MAS NMR spectra of HBC-C12




 -deuterated            fully protonated
                 CD 2
                                       H
           H            H
       H                    H         H
                                           0.180 nm
D2 C                            CD2


  H                             H
                                      0.196 nm
  H                             H


D2 C                            CD2
       H                    H
           H            H
               D 2C
Proposed stacking model based on solid state
                   NMR


                  H       H
              H               H




         H                        H
         H                        H




              H               H
                  H       H
„Graphitic“ stacking


        H     H
    H             H




H                      H
H                      H




    H             H
        H     H
     Spinning side band simulation in the DQ time
                       domain
For an isolated spin pair, using N cycles of the recoupling sequence for both the
excitation and reconversion of DQCs, the DQ time domain signal is given by:

                                3                                 
                           sin       Dsin 2 cos   R t1 N R
                                2                                
         S(t1 ,t2  0) 
                               sin     D sin2 cos N R 
                                       3
                                     2                       
                      0h H2
                                             and  are Euler angles relating the
        with      D
                     8 2 r 3               PAF of the diploar coupling tensor to
                                            the rotor fixed reference frame
 -> distance information in a rigid
 system, or indication of mobility:
            1  3cos2 
        f 
                 2                      Ref.: Graf et al. J. Chem. Phys. 1997, 106, 885
Homonuclear correlation between I = 1/2
               spins
                                aromatic protons at 8.3 ppm
DQ spinning                     (crystalline phase)
side band
patterns
                                             R = 35 kHz



    aromatic protons at 6.2 ppm (LC phase)


                                             R = 10 kHz




                                aliphatic protons at 1.2 ppm
                                (crystalline phase)


                                             R = 35 kHz



                                                           fitted dipolar coupling constants
Effect of additional phenyl spacers




R = -C12H25 or -C6H4-C12H25
    R




R       R




R       R




    R
Space filling model for HBC-PhC1
X-ray diffraction patterns of the mesophases
•Let us have a tour of solid state NMR
 following Professor Malcolm H. Levitt.

				
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