nmr

1. Two- Dimensional NMR
OR
2-D NMR
Mussawir Ali Mirza
Roll No. 16
University of Punjab

2. OBJECTIVES
1) 1-D NMR
Principle
Sequence Scheme
Name Proposed
2) 2-D NMR
Principle
Sequence Scheme
Name proposed
shapes of Signal
Why 2D NMR
Types

3. 1-D NMR
• Simple FT-NMR Technique
• 1-D NMR spectroscopy is simple technique In which we
provide 90 degree pulse to sample which is placed in
uniform magnetic field. As a result we get a FID signal
(raw form). To get meaningful data we apply Fourier
Transform program on FID to get desire signal.
• Data in form of frequency vs intensity is plotted along
x-axis and y-axis respectively

4. 1-D NMR

5. Sequence Scheme
If we divide the 1-D NMR into a general periods , we get
two steps
•Preparation
•Detection
Preparation : (do something with nuclei)
What we can do ???
•Simply we provide a 90 degree pulse
Detection: ( detect the signal)
•Simply we measure the signal

6. 1D NMR
Pulse Sequence
Scheme
Spectrum
(EtOH)

7. Why Named 1-D NMR ??
• We call it 1-D NMR ,
not because of graph.
Graph is actually in 2-d.
• Since one of the time
domain is changing into
frequency dimension,
That’s why we call it
1D NMR,
Time dimension changing
into frequency dimension

8. 2-D NMR
• The first two-dimensional experiment was proposed by
Jean Jenner.
• 2D NMR is a set of nuclear magnetic resonance
spectroscopy (NMR) methods which give data plotted in
a space defined by two frequency axes rather than one.
• 2D NMR spectra provide more information about a
molecule than one-dimensional NMR spectra.

9. Principle
• 2D NMR is Nuclear magnetic resonance spectroscopy in
which we provide a 90 degree pulse to our sample which
is placed in uniform magnetic field then we wait for
(0ms-5ms) depending upon the experiment type then
again we provide again 90 degree pulse and this time we
measure signal as FID.
• As a result we get Two FID signals which are plotted
with respect to time domain.
• To get a meaningful data , we apply Fourier transform
program on FIDs to get frequency in terms of ppm.

10. 1. Primary 2D matrix consists a series of FIDs.
2. A set of 1D NMR spectra is obtained by Fourier transformation
with respect to t2
3. The signals of each transformation may differ in amplitude and
phase. A second Fourier transformation with respect to t1 yields
the final 2D matrix with frequency axes F1 and F2
1. 2. 3.
2D NMR

11. 2D NMR Spectrum

12. PreparationPreparation:: 90 degree pulse excite nuclei in sample.
EvolutionEvolution (t1): let them nuclei precess freely.
MixingMixing: again 90 degree r.f. pulses are applied and create
transverse magnetization
DetectionDetection (t2): observable transverse magnetization is recorded.
It is usually labeled with t2
Four periods in 2D experiment

13. 2D NMR
Pulse Sequence

14. How 2D Spectrum is Recorded

15. How Data is Proceeded

16. Shapes of Signal

17. Signal Shapes

18. Signal Shapes

19. Double absorption Line

20. Why 2D NMR
• As 1D NMR spectrum
of Macromolecules is
quite complex.
• So make this complex
spectrum easy, we use
2D NMR.

21. Types of 2D NMR
• Homonuclear Experiment : In this experiment
we provide two frequency to same nuclei in sample. i.e.
H-H Correlation spectroscopy (COSY) Actually in it we
basically see homonuclear connectivity between same
nuclei.
• Heteronuclear Experiment : In this experiment
wo provides two frequency to different nuclei in the
sample i.e. H-C Heteronuclear Correlation (HETCOR).

22. H-H COSY Spectrum

23. H-H COSY Spectrum

24. HETCOR Spectrum

25. Thank you !!!!!