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NMR Spectrometer

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NMR Spectrometer Electromagnetic spectrum Nuclei Magnetic Resonance ... – PowerPoint PPT presentation

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Title: NMR Spectrometer


1
NMR Spectrometer
?????? ???????? ? ? ?
??????????????
2
Electromagnetic spectrum
3
Basic NMR Theory
1924 Pauli??????????????????? 1930 Stern
Gerlach?????????? 1939 Rabi???????? 1946
Bloch Purcell ?????????????, ?1952????????? 195
1 ???????????????? 1953 C13 ??????????? 1970
???????????
4
Nuclei Magnetic Resonance
  • N(nuclei) ???
  • ?????(????????)????
  • Magnetic Moment µ ?J ? Quantized!
  • ? nuclear gyromagnetic ratio
  • J spin angular momentum
  • M (magnetic field)??
  • ???????, B0
  • ???????? typically lt 3 Tesla
  • ???? 4.7-21.2 T (ca. 200-900 MHz for 1H)
  • R (resonance)??
  • ????????/????

5
????????????
No Magnetic Field Random Orientation
Magnetic Field Nuclei Aligned or Anti-Aligned
Z
Bo
x
Y
6
Basic NMR Theory
Z
N
N
N
S
Bo
Bo
N
S
Bo
S
S
x
Y
Lower energy More stable
Higher energy less stable
7
Basic NMR Theory
Z
Bo
Y
x
At each point of sample volume, vector sum of
nuclei averages to zero in X-Y plane
8
? ?
  • ?????????,??????????(a state)????(ßstate)???,?????
    ???????,?????????????

Energy
Strenght of applied Bo
9
????(Bo)????(?E)???
High Field NMR ?Increased sensitivity ? Increased
dispersion
ß spin state
Randomly oriented nuclei (no magnetic
field)
?E400MHz For 1H
?E200MHz For 1H
aspin state
Energy
4.7
9.4
10
NMR ? ? ? ? ??
Z
Z
?
M
rga
FID
????
??????
Y
Y
Z
X
X
????? MZ
??????
????
????
FT ??
LB, GB,
11
NMR?????
12
NMR Of Common Nuclei
Magnetic nuclei Nonmagnetic nuclei
1H 12C
13C 12C
2H 16O
14N 16O
19F 32S
31P 32S
No NMR observed
NMR observed
13
Chemical Shifts
  • 1H-NMR ??????1H ??????
  • ????(Chemical Shifts, ?) ????ppm(?????)???,?TMS(te
    tramethylsilane) ???,???0?
  • ????,NMR??????
  • 1H - NMR 0 15 ppm
  • 3C - NMR 0 300 ppm
  • 15N-NMR 0500 ppm

14
Common Spin Multiplicities
Protons Multiplet observed Ratio of intensities
1 2 3 4 5 6 Singlet Doublet Triplet Quartet Quintet Sextet 1 11 121 1331 14641 15101051
15
a
c
b
Ha
Hc
Hb
16
Chemical Shift
Solvent 1H NMR 13C NMR
Acetic Acid 11.65 (1) , 2.04 (5) 179.0 (1) , 20.0 (7)
Acetone 2.05 (5) 206.7 (13) , 29.9 (7)
Chloroform 7.26 (1) 77.2 (3)
Methanol 4.87 (1) , 3.31 (5) 49.1 (7)
Methylene Chloride 5.32 (3) 54.00 (5)
Pyridine 8.74 (1) , 7.58 (1) , 7.22 (1) 150.3 (1) , 135.9 (3) , 123.9 (5)
Water (D2O) 4.8
17
Coupling constant
  • ?1H-NMR ??,1H ?1H ???,???3 4 ??????,??????,?????
    ????,???????
  • ????,????????,??2nI 1 ??,??n ????1H ???,I
    ????????(I1/2)???,??????,??????,?Hz ????
  • Homonuclear coupling1H ??,???1H-NMR ?????
  • Heteronuclear coupling??1H ?????13C-?15N-NMR ?
  • ?????

18
Cryogenic Cooling System
Cryogenic Chiller
CryoBay
Turbo Pump
19
NMR Spectrometer
20
????
  • ????????(10 mg)
  • ?????D-solvent
  • ?????NMR sample tube
  • ??????(for 5mm tube)
  • ????? ?? 0.5 mL, 3 cm
  • SHIGEMI??? ?? 0.3 mL

????? (Depth Gauge)
21
??????(Depth Gauge)
??
Spinner (???)
?????
?????
?????? 20 mm for 5mm probe
??
22
???(Deuterium Lock)??(Shim)
23
??????
  • ????
  • ????
  • ?? ????(D1) 1 5 T1
  • ?? ????? (flip angle) 30 ? 60
  • ?? ????(DE) 6.5 usec
  • ?? ????(AQ) 1 AQ 3 sec
  • ?? ????(NS)

24
???NMR
25
Free Induction Decay
26
???FID
27
Fourier Transform
  • A mathematical technique that resolves a complex
    FID signal into the individual frequencies that
    add together to make it.

28
???FID???NMR??
29
2-ethyl indanone Proton 1H
30
2-ethyl indanone DEPT 13C
31
2-ethyl indanone gCOSY 1H-1H
32
2-ethyl indanone gHSQC 1H-13C
33
2-ethyl indanone NOESY-1D
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