1. NMR Nuclear Magnetic Resonance
NMR for Organometallic compounds
Index
NMR-basics
H-NMR
NMR-Symmetry
Heteronuclear-NMR
Dynamic-NMR
NMR and Organometallic compounds

2. NMR in Organometallic compounds spins 1/2 nuclei
For small molecules having nuclei I=1/2 : Sharp lines are expected
W1/2 (line width at half height) = 0-10 Hz
If the nuclei has very weak interactions with the environment,
Long relaxation time occur (109Ag => T1 up to 1000 s !!!)
This makes the detection quite difficult!

3. NMR in Organometallic compounds NMR properties of some spins 1/2 nuclei
Isotope
Nat. Abun-dance %
() 107 rad T-1 s-1
Frequency (MHz)
Rel. Receptivity 1H
99.985
100.0
1.00 3H -
28.535
106.7 --
3He
76.2
5.8 * 10-7
13C
1.11
6.7283
25.1
1.8 * 10-4
15N
0.37
-2.712
10.1
3.9 * 10-6
19F
25.181
94.1
8.3 * 10-1
29Si
4.7
19.9
3.7 * 10-4
31P
10.841
40.5
6.6 * 10-2
57Fe
2.2
0.8661
3.2
7.4 * 10-7
77Se
7.6
5.12
19.1
5.3 * 10-4
89Y
4.9
1.2 * 10-4
103Rh
-0.846
3.2 * 10-5
107Ag
51.8
-1.087
4.0
3.5 * 10-5
109Ag
48.2
-1.250
4.9 * 10-5
111Cd
12.8
21.2
1.2 * 10-3
113Cd
12.3
22.2
1.3 * 10-3
Index

4. Spin 1/2 Isotope Nat. Abundance %
Magnetogyric ratio () 107 rad T-1 s-1
Relative NMR frequency (MHz)
Rel. Receptivity
117Sn
7.6
-9.578
35.6
3.5 * 10-3
119Sn
8.6
37.3
4.5 * 10-3
125Te
7.0
-8.498
31.5
2.2 * 10-3
129Xe
26.4
-7.441
27.8
5.7 * 10-3
169Tm
100.0
-2.21
8.3
5.7 * 10-4
171Yb
14.3
4.712
17.6
7.8 * 10-4
183W
14.4
1.120
4.2
1.1 * 10-5
187Os
1.6
0.616
2.3
2.0 * 10-7
195Pt
33.8
5.768
21.4
3.4 * 10-3
199Hg
16.8
4.8154
17.9
9.8 * 10-4
203Tl
29.5
15.436
57.1
5.7 * 10-2
205Tl
70.5
15.589
57.6
1.4 * 10-1
207Pb
22.6
5.540
20.9
2.0 * 10-3

5. Multinuclear NMR
There are at least four other factors we must consider
Isotopic Abundance. Some nuclei such as 19F and 31P are 100% abundant (1H is %), but others such as 17O have such a low abundance (0.037%). Consider: 13C is only 1.1% abundant (need more scans than proton).
Sensitivity goes with the cube of the frequency. 103Rh (100% abundant but only sensitivity): obtaining a spectrum for the nucleus is generally impractical. However, the nucleus can still couple to other spin-active nuclei and provide useful information. In the case of rhodium, 103Rh coupling is easily observed in the 1H and 13C spectra and the JRhX can often be used to assign structures
Nuclear quadrupole. For spins greater than 1/2, the nuclear quadrupole moment is usually larger and the line widths may become excessively large.
Relaxation time

6. NMR in Organometallic compounds spins > 1/2 nuclei
These nuclei possess a quadrupole moment (deviation from spherical charge distribution) which cause extremely short relaxation time and extremely large linewidth W1/2 (up to 50 KHz)
W1/2 ~
(2I + 3) Q2 q2zz tc
I2 (2I -1)
Q = quadrupole moment
qzz = electric field gradient
tc = correlation time
I = spin quantum number
Narrow lines can be obtained for low molecular weight (small tc)
and if nuclei are embedded in ligand field of cubic (tetrahedral, octahedral) symmetry (qzz blocked)

7. NMR properties of some spins quadrupolar nuclei
Isotope
Spin
Abun-dance %
() 107 rad T-1 s-1
Freq. (MHz)
Rel. Recep-tivity
Quadrupole moment m2 2H 1
0.015
4.1066
15.4
1.5 * 10-6
2.8 * 10-3
6Li
7.4
3.9371
14.7
6.3 * 10-4
-8 * 10-4
7Li
3/2
92.6
38.9
2.7 * 10-1
-4 * 10-2
9Be
100.0
14.1
1.4 * 10-2
5 * 10-2
10B 3
19.6
2.8746
10.7
3.9 * 10-3
8.5 * 10-2
11B
80.4
8.5843
32.1
1.3 * 10-1
4.1 * 10-2
14N
99.6
1.9338
7.2
1.0 * 10-3
1 * 10-2
17O
5/2
0.037
13.6
1.1 * 10-5
-2.6 * 10-2
23Na
7.0801
26.5
9.3 * 10-2
1 * 10-1
25Mg
10.1
-1.639
6.1
2.7 * 10-4
2.2 * 10-1
27Al
6.9760
26.1
2.1 * 10-1
1.5 * 10-1
33S
0.76
2.055
7.7
1.7 * 10-5
-5.5 * 10-2
35Cl
75.5
2.6240
9.8
3.6 * 10-3
-1 * 10-1
37Cl
24.5
2.1842
8.2
6.7 * 10-4
-7.9 * 10-2
39K
93.1
1.2498
4.7
4.8 * 10-4
4.9 * 10-2
47Ti
7.3
5.6
1.5 * 10-4
2.9 * 10-1
49Ti
7/2
5.5
2.1 * 10-4
2.4 * 10-1
51V
99.8
7.0453
26.3
3.8 * 10-1
-5 * 10-2
55Mn
6.608
24.7
1.8 * 10-1
4 * 10-1

8. Quadrupolar nuclei: Oxygen-17
NMR – From Spectra to Structures An Experimental approach Second edition (2007) Springler-Verlag
Terence N. Mitchellm Burkhard Costisella

9. Notable nuclei
19F: spin ½, abundance 100%, sensitivity (H=1.0) : JH-F = 45 Hz, 3JH-F trans = 17 Hz, 3JH-F Cis = 6 Hz 2JF-F = 300 Hz, 3JF-F = - 27 Hz
29Si: spin ½, abundance 4.7%, sensitivity (H=1.0) : The inductive effect of Si typically moves 1H NMR aliphatic resonances upfield to approximately 0 to 0.5 ppm, making assignment of Si-containing groups rather easy. In addition, both carbon and proton spectra display Si satellites comprising 4.7% of the signal intensity.
31P: spin ½, abundance 100%, sensitivity (H=1.0) : JH-P = 200 Hz, 2JH-P ~2-20 Hz, 1JP-P = 110 Hz, 2JF-P ~ Hz, 3JP-P = 1-27 Hz the chemical shift range is not as diagnostic as with other nuclei, the magnitude of the X-P coupling constants is terrific for the assignment of structures Karplus angle relationship works quite well

10. See Selnau, H. E.; Merola, J. S. Organometallics, 1993, 5, 1583-1591.
Notable nuclei
31P: spin ½, abundance 100%, sensitivity (H=1.0) : JH-P = 200 Hz, 2JH-P ~2-20 Hz, 1JP-P = 110 Hz, 2JF-P ~ Hz, 3JP-P = 1-27 Hz the chemical shift range is not as diagnostic as with other nuclei, the magnitude of the X-P coupling constants is terrific for the assignment of structures Karplus angle relationship works quite well
2JH-P is Hz for the phosphine trans to the hydride, but only 19.8 Hz to the (chemically equivalent) cis phosphines.
See Selnau, H. E.; Merola, J. S. Organometallics, 1993, 5,

11. Notable nuclei
103Rh: spin ½, abundance 100%, sensitivity (H=1.0) : JRh-C = Hz, 1JRh-C(Cp) = 4 Hz,
For example, in the 13C NMR spectrum of this linked Cp, tricarbonyl Rh dimer at 240K (the dimer undergoes fluxional bridge-terminal exchange at higher temperatures),
the bridging carbonyl is observed at d and is a triplet with 1JRh-C = 46 Hz. The equivalent terminal carbonyls occur as a doublet at d with 1JRh-C = 84 Hz:
See Bitterwolf, T. E., Gambaro, A., Gottardi, F., Valle G Organometallics, 1991, 6,

12. Chemical shift for organometallic
In molecules, the nuclei are screened by the electrons.
So the effective field at the nucleus is:
Beff = B0(1-)
Where  is the shielding constant.
The shielding constant has 2 terms: d (diamagnetic) and p (paramagnetic)
d - depends on electron distribution in the ground state
p - depends on excited state as well. It is zero for electrons in s-orbital.
This is why the proton shift is dominated by the diamagnetic term.
But heavier nuclei are dominated by the paramagnetic term.
Index

13. Symmetry
Non-equivalent nuclei could "by accident" have the same shift and this could cause confusion.
Some Non-equivalent group might also become equivalent due to some averaging process that is fast on NMR time scale. (rate of exchange is greater than the chemical shift difference)
e.g. PF5 : Fluorine are equivalent at room temperature (equatorial and axial positions are exchanging by pseudorotation)
Index

14. Symmetry in Boron compounds

15. Proton - NMR
Increasing the 1 s orbital density increases the shielding
M = C
M = Si
M = Ge
MH4
0.1
3.2
3.1
MH3I
2.0
3.4
3.5
MH3Br
2.5
4.2
4.5
MH3Cl
2.8
4.6
5.1
(MH3)2O
5.3
MH3F
4.1
4.8
5.7
Shift to low field when the metal is heavier (SnH4 -  = 3.9 ppm)
Index

16. Proton – NMR : Chemical shift
Further contribution to shielding / deshielding is the anisotropic magnetic susceptibility from neighboring groups (e.g. Alkenes, Aromatic rings -> deshielding in the plane of the bound)
In transition metal complexes there are often low-lying excited electronic states. When magnetic field is applied, it has the effect of mixing these to some extent with the ground state.
Therefore the paramagnetic term is important for those nuclei themselves => large high frequency shifts (low field). The protons bound to these will be shielded ( => 0 to -40 ppm) (these resonances are good diagnostic. )
For transition metal hydride this range should be extended to 70 ppm!
If paramagnetic species are to be included, the range can go to 1000 ppm!!
Index

17. Proton NMR and other nuclei
The usual range for proton NMR is quite small if we compare to other nuclei:
13C => 400 ppm
19F => 900 ppm
195Pt => 13,000 ppm !!!
Advantage of proton NMR : Solvent effects are relatively small
Disadvantage: peak overlap
Index

18. Chemical shifts of other element
There is no room to discuss all chemical shifts for all elements in the periodical table. The discussion will be limited to 13C, 19F, 31P *as these are so widely used.
 Alkali Organometallics (lithium) will be briefly discuss
For heavier non-metal element we will discuss 77Se and 125Te.
 For transition metal, we will discuss 55Mn and 195Pt
Index

19. Alkali organometallics: Organolithium
For Lithium: we have the choice between 2 nuclei:
6Li : Q=8.0*10-4 a=7.4% I=1
7Li : Q=4.5*10-2 a=92.6% I=3/2
6Li : Higher resolution 7Li : Higher sensitivity
7Li NMR : larger diversity of bonding compare to Na-Cs (ionic)
Solvent effects are important (solvating power affects the polarity of Li-C bond and govern degree of association
d covers a small range: 10 ppm
Covalent compound appear at low field (2 ppm range)
Coupling 1JC-Li between carbon and Lithium indicate covalent bond

20. Organolithium

21. Boron NMR For Boron: we have the choice between 2 nuclei:
10B : Q= 8.5 * a=19.6% I=3
11B : Q= 4.1 * 10-2 a=80.4% I=3/2
11B : Higher sensitivity

22. Boron NMR

23. Boron NMR

24. 11B coupling with Fluorine: 19F-NMR
10B : Q= 8.5 * a=19.6% n= I=3
2nI+1 = 7
11B : Q= 4.1 * 10-2 a=80.4% n= I=3/2
2nI+1 = 4
Boron can couple to other nuclei as shown here on 19F-NMR
Isotopic shift
19F-NMR
11BF4
NaBF4 / D2O
JF-10B
JF-11B =
n10B
n11B
10BF4
JBF=0.5 Hz
JBF=1.4 Hz

25. C13 shifts
Saturated Carbon appear between ppm with electronegative substituents increasing the shifts.
CH3-X : directly related to the electronegativity of X.
The effects are non-additive: CH2XY cannot be easily predicted
Shifts for aromatic compounds appear between ppm
-bonded metal alkene may be shifted up to 100 ppm: shift depends on the mode of coordination
one extreme shift is CI4  = -293 ppm !!!
Metal carbonyls are found between ppm. (very long relaxation time make their detection very difficult)
Metal carbene have resonances between ppm
Index

26. Oxidation state of neighbor Stereochemistry
F-19 shifts
Wide range: 900 ppm! And are not easy to interpret. The accepted reference is now: CCl3F. With literature chemical shift, care must be taken to ensure they referenced their shifts properly.
Sensitive to:
electronegativity
Oxidation state of neighbor
Stereochemistry
Effect of more distant group
Index

27. F-19 shifts
The wide shift scale allow to observe all the products in the reaction of : WF6 + WCl6 --> WFnCln-6 (n=1-6)
Index

28. Sn shifts

29. H-NMR of Sn compound 2JSN119-H = 54.3 Hz 2JSN117-H
NMR – From Spectra to Structures An Experimental approach Second edition (2007) Springler-Verlag
Terence N. Mitchellm Burkhard Costisella
3 isotopes with spin ½ :
Sn-115 a=0.35%
Sn-117 a=7.61%
Sn-119 a=8.58%
H-NMR of Sn compound
2JSN119-H = * 2JSN117-H
(ratio of g of the 2 isotopes)
2JSN119-H = 54.3 Hz
2JSN117-H

30. Sn-119 3 isotopes with spin ½ : Sn-115 a=0.35% Sn-117 a=7.61%
NMR – From Spectra to Structures An Experimental approach Second edition (2007) Springler-Verlag
Terence N. Mitchellm Burkhard Costisella
Sn-119
3 isotopes with spin ½ :
Sn-115 a=0.35%
Sn-117 a=7.61%
Sn-119 a=8.58%

31. Sn-119 coupling 1- molecule containing 1 Sn-119
2- molecule containing Sn119, Sn117
J between Sn-119 and Sn-117
3- molecule containing two Sn119
Form an AB spectra (J=684 Hz)
4- molecule containing Sn119 and C13
J between Sn119 and C13
Sn-117 a=7.61%
Sn-119 a=8.58%

32. Dynamic NMR
p261

33. C13

34. Cycloheptatriene

35. Dynamic NMR

36. 1H-NMR

37. P-31 Shifts The range of shifts is ± 250 ppm from H3PO4 Extremes:
- 460 ppm for P4
+1,362 ppm phosphinidene complexe: tBuP[Cr(CO)5]2
Interpretation of the shifts is not easy : there seems to be many contributing factors
PIII covers the whole normal range: strongly substituent dependant
PV narrower range:  - 50 to 
Unknown can be predicted by extrapolation or interpolation
PX2Y or PY3 can be predicted from those for PX3 and PXY2
The best is to compare with literature values.
Index

38. P-31 Shifts
Index

39. Other nuclei: Selenium, Telurium
There are many analogies between Phosphorus and Selenium chemistry.
There are also analogies between the chemical shifts of 31P and 77Se but the effect are much larger in Selenium!
For example:
Se(SiH3)2 and P(SiH3)3 are very close to the low frequency limit (high field)
The shifts in the series SeR2 and PR3 increase in the order R= Me < Et < Pri < But
There is also a remarkable correlation between 77Se and 125Te. (see picture next slide)
Index

40. Correlation between Tellurium and Selenium Shifts
Index

41. Manganese-55
Manganese-55 can be easily observed in NMR but due to it’s large quadrupole moment it produces broad lines
10 Hz for symmetrical environment e.g. MnO4-
10,000 Hz for some carbonyl compounds.
It’s shift range is => 3,000 ppm
As with other metals, there is a relationship between the oxidation state and chemical shielding
Reference: MnVII : d = 0 ppm (MnO4-)
MnI : d –1000 to –1500
Mn-I : d –1500 to -3000
55Mn chemical shifts seems to reflect the total electron density on the metal atom
Index

42. Pt-195 Shifts
I = ½ a=33.8% K2PtCl6 ref set to 0. Scale: to ppm !!
Platinum is a heavy transition element. It has wide chemical shift scale: 13,000 ppm!
The shifts depends strongly on the donor atom but vary little with long range. For example: PtCl2(PR3)2 have very similar shifts with different R
Many platinum complexes have been studied by 1H, 13C and 31P NMR. But products not involving those nuclei can be missed : PtCl42-
Major part of Pt NMR studies deals with phosphine ligands as these can be easily studied with P-31 NMR.
Lines are broad (large CSA) large temperature dependence (1 ppm per degree)
Index

43. Pt-195 : coupling with protons
CSA relaxation on 195Pt can have unexpected influence on proton satellites. CSA relaxation increases with the square of the field. If the relaxation (time necessary for the spins to changes their spin state) is fast compare to the coupling, the coupling can even disapear!
1H-NMR
CH2=CH2
a=33.8%

44. Pt-195 I = ½ a=33.8% H6 : dd J4-6 = 1.3 Hz J5-6 = 6.2 Hz
NMR – From Spectra to Structures An Experimental approach Second edition (2007) Springler-Verlag
Terence N. Mitchellm Burkhard Costisella
Pt-195
I = ½ a=33.8%
H6 : dd
J4-6 = 1.3 Hz
J5-6 = 6.2 Hz
JH6-Pt195 = 26 Hz

45. Pople Notation
Spin > ½ are generally omitted.
Index

46. Effect of Coupling with exotic nuclei in NMR
Natural abundance 100%
1H, 19F, 31P, 103Rh : all have 100% natural abundance.
When these nuclei are present in a molecule, scalar coupling must be present. Giving rise to multiplets of n+1 lines.
One bond coupling can have hundreds or thousands of Hz.
They are an order of magnitude smaller per extra bound between the nuclei involved. Usually coupling occur up to 3-4 bounds.
Example:
P(SiH3)3 + LiMe -> Product : P-31 NMR shows septet ===> product is then P(SiH3)2-
Index

47. P-31 Spectrum of PF2H(NH2)2 labeled with 15N
1JP-H t t
Triplet 1JP-N
Quintet 2JP-H
1JP-F
1JP-F
2 x 3 x 3 x 5 = 90 lines !
coupling with H (largest coupling : Doublet)
then we see triplet with large coupling with fluorine
With further Coupling to 2 N produce triplets, further coupled to 4protons => quintets

48. Effect of Coupling with exotic nuclei in NMR
Low abundance nuclei of spin 1/2
13C, 29Si, 117Sn, 119Sn, 183W : should show scalar coupling
=> satellite signals around the major isotope.
For example: WF6 as 183W has 14% abundance, the fluorine spectra should show satellite signals separated by the coupling constant between fluorine and tungsten. The central signal has 86% intensity and the satellites have 14%. This will produce 1:12:1 pattern
Index

49. Si-29 coupling
29Si has 5% abundance.
For H3Si-SiH3 , the chance of finding
H3-28Si--29Si-H3 is 10%. Interestingly we can see that the two kind of protons are no longer equivalent so homonuclear coupling become observable! The molecule with 2 Si-29 is present with 0.25% intensity and is difficult to observe.
The second group gives smaller coupling
Index

50. Coupling with Platinum
195Pt the abundance is 33%.
Platinum specie will give rise to satellite signal with a relative ratio of 1 : 4 : 1. This intensity pattern is diagnostic for the presence of platinum.
If the atom is coupled to 2 Pt, the situation is more complex:
2/3 x 2/3 => no Pt spin (central resonance)
1/3 x 1/3 => two Pt with spin 1/2 => triplet
remaining molecule has 2x (1/3 x 2/3) = 4/9 => one Pt with spin 1/2 => doublet
 Adding the various components together we now have 1:8:18:8:1 pattern. The weak outer lines are often missed, leaving what appear to be a triplet 1:2:1 !!!
Index

51. Carbon-13 in organometallic NMR
13C is extremely useful to organometallic NMR
For example:
Palladium complexe has:
4 non-equivalent Methyls
2 methylenes
Allyl : 1 methylene, 2 methynyl
Phenyl: 4 C: mono-subst.
Index

52. 29Si-NMR Polymeric siloxanes are easily studied by NMR: These have
terminal R3SiO-
Chain R2Si (O-)2
Branch R-Si(O-)3
Quaternary Si(O-)4
All these Silicon have different shifts making it possible to study the degree of polymerization and cross-linking
Index

53. Coupling with Quadrupolar Nuclei (I>1/2)
2nI + 1 lines
The observation of such coupling depends on the relaxation rate of the quadrupolar nuclei (respect to coupling constant)
Index

54. Coupling with Quadrupolar Nuclei (I>1/2)

55. Factors contributing to Coupling constant
Magnetic Moment of one nuclei interact with the field produced by orbital motion of the electrons – which in turn interact with the second nuclei.
There is a dipole interaction involving the electron spin magnetic moment
There is also a contribution from spins of electrons which have non-zero probability of being at the nucleus => Fermi contact
Index

56. 1-bound coupling Depends on s-orbital character of the bound
Hybridization of the nuclei involved 1JCH => 125 (sp3), 160 (sp2), 250 (sp)
Electronegativity is another factor: increase the coupling
CCl3H => 1JCH = 209 Hz
Coupling can be used to determine coordination number of PF , PH compounds, and to distinguish axial, equatorial orientation of Fluorines.
1JPH = 180 (3 coordinate) , 1JPH = 400 (4 coordinate)
Coupling can also be used to distinguish single double bond
E.g.
Index

57. 2-bound coupling
2J can give structural information: There is a relationship between 2J and Bond angle
=> coupling range passes through zero. Therefore the sign of the coupling must be determined
Index

58. 3-bound coupling
Depends on Dihedral angle 3JXY = A cos 2f + B cos f + C A, B, C : empirical constants
Index

59. Complicated proton spectra : CH3-CH2-S-PF2
Almost quintet
Index

60. Complicated Fluorine spectra : PF2-S-PF2
Second order spectra: 19F
Chemically equivalent
Magnetically non-equivalent
1JPF different from 3JPH
This type of spectra is frequent in transition metal complex:
MCl2(PR3)2
Index

61. Equivalence and non-equivalence
F are Non-Equivalent
The 2 phosphorus are Pro-chiral: non-equivalent
Index

62. To identify a compound: PF215NHSiH3
Use as many techniques as possible
Proton nmr spectra is difficult to analyze with so many J’s
But with 19F, 15N and 31P spectra it’s easier (get heteronuclear J)
Index

63. To identify a compound: PF215NHSiH3
Use as many techniques as possible
Using decoupler : easier analysis
Index

64. Multinuclear Approach
Proton NMR spectra: 3 groups of peaks integrating for 12:4:1
Resonances due to Methyl and CH2 have coupling with 31P
And also shows satellites due to mercury coupling (199Hg 16.8%)
While third resonance is broad
In 31P, there is a single signal: Symmetrical compound: that has
Mercury satellites
In 199Hg NMR (with proton decoupling): quintet demonstrate the
presence of 4 Phosphorus
Index

65. Heteronuclear NOE
NOE enhancement can give useful gain in signal-to-noise
It is most efficient when the heteronuclei is bound to proton
NOEMAX = 1 + gH/2gX
For nuclei having negative g, NOE is negative (for 29Si, max=-1.5)
Index

66. Exchange : DNMR – Dynamic NMR
NMR is a convenient way to study rate of reactions – provided that the lifetime of participating species are comparable to NMR time scale (10-5 s)
At low temperature, hydrogens form an A2B2X spin system
At higher temperature germanium hop from one C to the next
Index

67. Paramagnetic compounds in NMR
Usually paramegnetic compounds are too braod => give ESR
In NMR, Chemical shift is greatly expanded
Paramagnetic shifts are made up of 2 component:
Through space Dipolar interaction between the magnetic moment of the electron and of the nucleus
Contact Shift: coupling between electron and nucleus. This interaction would give a doublet in NMR but J ~ millions of Hertz!! With such large coupling, intensity of the 2 resonances are not equal => weighted mean position is not midway With fast relaxation, collapse of the multiplet may fall thousands Hertz away from expected position => Contact Shift
Contact Shift give a measure of unpaired spin density at resonating Nucleus.
Useful for studying spin distribution in organic radical or in ligands in organo metallic complexes

68. Paramagnetic compounds in NMR
4 sets of resonances:
1 symmetrical Fac: the 3 ligand are identical 3 Asymetrical ligand in Mer occur with 3 time the probability.

69. NMR and Organometallic compounds
Index
NMR-basics
H-NMR
NMR-Symmetry
Heteronuclear-NMR
Dynamic-NMR
NMR and Organometallic compounds
Special 1D-NMR