Nuclear magnetic resonance spectroscopy (NMR) is a powerful analytical technique used to characterize the structure of organic molecules. NMR works by applying an external magnetic field to atomic nuclei, causing them to absorb and emit radio frequencies that provide information about their local chemical environment. There are two main types of NMR: proton (1H) NMR determines the number and type of hydrogen atoms in a molecule, while carbon-13 (13C) NMR determines the number and type of carbon atoms. NMR spectroscopy has been developed since its discovery in 1946 and now allows determination of complex molecular structures. It provides detailed information about molecular structure, dynamics, reactions, and chemical environments.

1. TOPIC : NUCLEAR MAGNETIC RESONANCE SPECTROSCOPY
SESSION: 2022-23
PRESENTED BY : POOJA MOHOD
MSC – II (SEM - 3)
Department of chemistry

2. CONTENT
 Spectroscopy
 Important milestone
 Introduction
 Types of NMR
 Instrumentation
 Working
 Principle

3. UNKNOWN
COMPOUND
MATTER
SPECTROSCOPY
UV
IR
NMR
MASS
INTERACTION OF LIGHT WITH MATTER
USES OF SPECTROSCOPY
• You can find out the quantity of any substance.
• To find out the structure of unknown substance.

4. 2009: First Gigahertz NMR spectrometer.
1985: Protein structures.
1971: First 2D NMR experiment by Cosy
1969: First concept of MRI scanners.
1968: First pulse fourier transform NMR.
1962: First superconducting magnet for NMR.
1952: First commercial NMR spectrometer.
1946: NMR of liquid and solid by Purcell and Bloch.
1938: NMR in molecular beams Rabi (Columbia university)

5.  It is a powerful analytical technique used to characterized the structure of
organic molecules by identifying carbon- hydrogen frameworks within
molecules.
 I is nuclear spin quantum number and the value of I depend upon atomic
number and mass number and spin property of nucleus.
 NMR active or inactive :
 ACTIVE:
 INACTIVE:
Even
Odd
Odd
Even
Odd
Odd
Even
Even

6. There are two types of NMR:-
H-NMR :- It is used to determine the type and number of H-
atom in a molecule.
C-NMR :- It is used to determine the tyoe and number of C –
atom in a molecule.

7. Instrumentation

8. Working
1) The sample is placed in a magnetic field and NMR
signal is produced by excitation of nuclei sample with radio
wave into NMR.
2) The intramolecular magnetic field around and atom in a
molecule changes the resonance frequency thus giving
excess to detail of the electronic structure of the
molecule and its individual functional group.
3) As the field are unique or highly characteristics to
individual compounds NMR spectroscopy is the
definitive method to identify monomolecular organic
compound.
4) Beside identification NMR spectroscopy provides
detailed information about the structure dynamic
reaction state and chemical environment of molecules.

9. Principle
1) The principle behind NMR is that many nuclei have
spin and all nuclei are electrically charged. If an
external magnetic field is applied an energy transfer is
possible between the base energy to a higher energy
level.
2) The energy transfer takes place at a wavelength that
correspond to radio frequencies and when the spin
return to its base level energy is emitted at the same
frequency.
3) The signal that matches this transfer it measured in
many ways and processed in order to yield and NMR
spectrum for the nucleus spectrum.

10. Thank you