This document discusses 1D and 2D NMR spectroscopy techniques. It defines 1D and 2D NMR, and describes their principles and applications. Key types of 1D NMR techniques discussed include regular, decoupled, and gated decoupling NMR. 2D NMR techniques covered include COSY, NOESY, HSQC, and HMBC. Examples are provided to illustrate how these techniques can be used to analyze molecular structure.

1. PRESENTED BY
DIVYA V
1ST M PHARM
PHARMACEUTICAL CHEMISTRY
PRESENTED BY
DIVYA V
1ST M PHARM
PHARMACEUTICAL CHEMISTRY

2.  1D NMR
 2D NMR
 COSY
 NOESY

3.  It is a type of spectroscopy where the energy
states of spin-active nucleus placed in a
static magnetic field are interogated by
inducing transitions between the states via
radiofrequency irradiation.
 Contain sequence of radio frequency pulses.
 Plot-Chemical shift vs radiofrequency.
 Includes regular H-proton spectrum, C-13
spectra.

4.  PRINCIPLE
 Consist of 2 sections
#Preparation
#Detection
PREPARATION-A 90 ͦ pulse is applied which
rotates the equilibrium magnetization along
Z axis to Y axis

5.  This induces a signal in receiver coil.
 The signal decays due to T2 relaxation & is
called as FREE INDUCTION DECAY(FID)
 FOURIER TRANSFORMATION to get final 1D
spectrum.

6. TYPES
 REGULAR
 Sample reaches equilibrium.
 RF signal is transmitted.
 Signal is evolved(FID)
 Fourier transformation
 Final spectra is obtained

7.  DECOUPLED
 Heteronuclear coupling from another nucleus
with magnetic spin causes the signal to split
& sensitivity to fall.
 Apply decoupling is necessary.
 GATED DECOUPLING
 Apply decoupling during relaxation time.

8.  OTHER METHODS OF DECOUPLING,
-Off resonance
-Solvent suppression
-Deuterium substitution
 Nuclear overhauser effect
 The local field of one nucleus is
affected by another nucleus.
 Causes reduction in intensity
of signal.

9.  1D NMR SPECTRAL ANALYSIS
 Contain following information for analysis,
#Chemical shift
#Spin-Spin coupling
#Intensity
INTERPRETATION OF H-NMR
 No:of signals-Indicates how many different
kinds of protons are present.
 Position of signals: Chemical shift.
 Intensity of signals: No:of protons.
 Splitting of signals: No:of nearby nuclei
usually protons.

10.  ANALYSIS OF C-13 NMR
E.g. Propyl acetate

11. 2D NMR

12. DEFINITION
 It gives data plotted in space defined by 2
frequency axes rather than one.

13.  PRINCIPLE
 A 90 ͦ pulse is provided to sample & then
depending upon the type again a 90 ͦ pulse
is provided & this time, signal FID is
measured.

14.  STAGES OF 2D NMR

15. TYPES
# HOMONUCLEAR THROUGH-BOND
CORRELATION METHODS
*COSY *ECOSY *TOCSY *INADEQUATE
# HOMONUCLEAR THROUGH BOND-
CORRELATION METHODS
*HSQC *HMBC *HETCOR
# THROUGH SPACE CORRELATION METHODS
*NOESY *ROESY

16. HOMONUCLEAR
 2 Frequency is provided to same nuclei in
sample.
COSY
 Used to identify spins which are coupled to
each other.
 2 axes are proton chemical shift.
 Consist of 2 types of peaks
* Diagonal peaks
* Cross peaks
 Diagonal peak-Corresponds to normal 1D
spectrum.
 Cross peak-Spin-Spin coupling.

17.  Cross peaks appears in matched positions in
the diagonal peaks.
TYPES
 A)NORMAL COSY PULSE SEQUENCE

18.  B)COSY 45 ͦ PULSE SEQUENCE
 C)LONG RANGE COSY PULSE SEQUENCE

19.  D)MQF COSY PULSE SEQUENCE
 E.G. GERANIOL
2
13
4
5
6
7
CH3
8
CH3
9
CH3
10
OH

20.  E.G. ASPIRIN
1
2
6
3
5
4
7
O OH
O
8 9
O
CH3

21. Fig;Cosy spectrum of aspirin

22. THROUGH SPACE CORRELATION METHODS
NUCLEAR OVER-HAUSER EFFECT
SPECTROSCOPY(NOESY)
 Developed to observe NOE in 2D
spectroscopy.
 Useful in structural elucidation.
Fig : Pulse in NOESY

23.  E.g. 12,14-ditbutylbenzochrysene.

24. Fig NOESY spectrum 12,14ditbutylbenzochrysene.

25. REFERENCES
 Spectrophotometric identification of organic
compounds by Silverstein, Barsler and Morril.
Fifth edition;227-267.
 Instrumental methods of chemical analysis by
Gurdeep.R.Chatwal and Sham.k.Anand.
Himalaya publishing house:4.73-5.63
 1D and 2D NMR experiment methods by
Dr.Shaoxiong.Wu : April 14:2011