NMR SPECTROSCOPY.pptx

SMT BNB SWAMINARYAN PHARMACY COLLEGE ,SALVAV
NMR
SPECTROSCOPY
PRESENTED BY :- OZA VRUSHNAT PRANAY
CLASS :- M.PHARM (PHARMACEUTICS) SEM 1

05-01-2023 smtbnbspc/vrushantoza/ 2
CONTENT
CONTENT
RELAXATION PROCESS AND
CHEMICAL SHIFT
SOLVENT REQUERED
INSTRUMENTATION
INTODUCTION
QUANTUM NUMBER
AND THEIR ROLE
THEORY & PRINCIPLE

INTRODUCTION
N
M
R
MEGNETIC
NUCLEAR RESONANCE
• Proton in nucleus shows spin movement because of that proton acts as small magnet
• Due to this the resonance in this small magnet takes place and processes NMR
• Range : 4-600 MHz

QUANTUM NUMBER
AND THEIR ROLE
• Describe shape of
orbit .
• Value of I depends
on N.
• Have + or – value .
• Specify the orientation
• This number divides
the subshell into
individual orbital
which hold the
electron.
• Describes angular
momentum of
electron.
• Because angular
momentum is
vector spin
quantum number
has both
magnitude and
direction .
 Definition:- occurs in the theoretical expression for the value of some quantized property of a subatomic
particle , atom or molecules and can only have certain integer or half integer value.
 In simple term :- Quantum number is set of number use to describe position and energy of electron in atom.
 It has 4 types
1. Principal(N) 2.Angular
momentum(I)
3.Magnetic(M) 4. Spin (S)
• The main energy
level occupied by
the electrons
• Energy level are
fixed distance from
nucleus of given
atom
• Described in whole
number

QUANTUM NUMBER
AND THEIR ROLE

• The theory behind NMR comes from the spin of a nucleus and it generates magnetic field.
• Without external applied magnetic field the nuclear spin are random in direction.
• When external magnetic field (B0) is present the nuclei aligned themselves either with or against the field of
external magnet.
Theory & Principle
 THEORY

Theory & Principle

The spinning nucleus
The effect of external magnetic field
Precessional motion
Precessional frequency
Energy transition
Theory & Principle
 PRINCIPLE

1) THE SPINNING NUCLEUS:-
 The nucleus of the hydrogen (proton)
behaves as a tiny spinning bar
magnet,
 and it does so because it possesses
both electric charge and mechanical
spin
 any spinning charged body will
generate a magnetic field, and the
nucleus of hydrogen is no exception
Theory & Principle
 PRINCIPLE

2) The effect of external magnetic field
 The proton can only adopt two orientations
with respect to an external magnetic
 field-either aligned with the field (the
lower energy state)
Or
 opposed to the field (the higher energy
state).
Theory & Principle
 PRINCIPLE

3) Precessional motion
 Proton will be showing precessional motion
due to interaction of spin & gravitational
force of earth [gyroscopic motion ]
 Energy of reorientation of magnetic dipole
∆E=hv
Where ,
H= plank’s constant
V= frequency of radiation
Theory & Principle
 PRINCIPLE

4) Precessional frequency
 Spinning frequency of proton will be same
 Precessional frequency ∝ external magnetic
force
v ∝ Bo
Theory & Principle
 PRINCIPLE

5) Energy transition
 If proton’s precessional frequency will be exactly same then only it will absorb the radiation and
resonance takes place which is know as NMR
 Proton goes to low energy level to high energy level.
 The emitted radiofrequency signal gives the NMR spectrum of the concerned nucleus.
 The emitted radiofrequency is directly proportional to the strength of the applied magnetic field
Theory & Principle
 PRINCIPLE

SAMPLE TUBE / HOLDER
MAGNET
SWEEP GENERATOR
RADION FREQUANCY
GENRATOR
RF RECEIVER
READ OUT DEVICE /
DETECTORE
INSTRUMENTATION
 INSTRUMENTATION

INSTRUMENTATION
 INSTRUMENTATION

INSTRUMENTATION
 INSTRUMENTATION
1.SAMPLE HOLDER:
5mm GLASS TUBE IS USED,
WHICH CAN HOLD 0.4ml
LIQUID SAMPLE.
MICROTUBES ARE USED FOR
LOW VOLUMES.
2.MAGNET:
• ACCURACY & QUALITY OF THE INSTRUMENT IS DEPENDENT ON
ITS STRENGTH.
• RESOLUTION INCREASES WITH INCREASE IN THE FIELD
STRENGTH.
• THREE TYPES OF MAGNETS CAN BE USED
• CONVENTIONAL MAGNET (30 - 60MHz)
• PERMANENT MAGNET (60,90, 100MHz)
• SUPER CONDUCTING MAGNET (470MHz)
3.SWEEP GENERATOR:
A SET OF SWEEP COIL IS LOCATED PARALLEL TO THE
MAGNET, WHICH ALLOWS THE MAGNETIC FIELD TO SWEEP

INSTRUMENTATION
 INSTRUMENTATION
4. RF TRANSMITTER / GENERATOR :
• IT IS A PAIR OF COILS MOUNTED PERPENDICULAR
TO THE PATH OF FIELD & RECIEVER COIL.
5. RECIEVER COIL & AMPLIFIER:
• AMPLIFIES THE RECEIVED EMR BY 10 5
TIMES.
6. DETECTOR:
• DETECTS THE SIGNAL PRODUCED
BY RESONATING NUCLEI.

SOLVENT USED
IN NMR
 CRITERIAS
CHEMICALLY INERT
SOLVENTS SHOULD
BE MAGNETICALLY
ISOTROPIC IN
NATURE
FREE FROM ANY
HYDROGEN ATOM
SOLVENT SHOULD
BE ABLE TO
DISSOLVE THE
MOLECULARAMPLE
IN A RESONABLE
QUANTITY.
COMMONLY USED SOLVENTS:
CARBON TETRACHOLRIDE(CCL4)
CARBON DISULPHIDE(CS2)
DEUTEROCHLOROFORM(CDCI3)
HEXACHLOROACETONE((CDCI,),CO),
DEUTEROBENZENE(C;D.).
DEUTERODIMETHYLSULFOXIDE((CH;)250)

RELEXATION
PROCESS
 RELEXARION
PROCESS
 RELAXATION IS PROCESS BY WHICH THE
SPINS IN THE SAMPLE COME TO
EQUILLIBRIUM WITH THE SURROUNDINGS.
 RATE OF RELAXATION:
 DETERMINES HOW FAST AN EXPERIMENT
CAN BE REPEATED
 INFLUENCED BY THE PHYSICAL
PROPERTIES OF MOLECULE & THE SAMPLE
 AN UNDERSTANDING OF RELAXATION
PROCESSES IS IMPORTANT FOR THE PROPER
MEASUREMENT & INTERPRETATION OF NMR
SPECTRA.
1. SPIN LETICE /LONGITUDINAL RELAXATION :
 CHARACTERISED BY T1 NUCLEI IN UPPER
STATE STARTS TO LOSE ENERGY TO THE
SURROUNDING .
2.SPIN-SPIN/ TRANSVERSE RELAXATION:
 CHARACTERISED BY T2 DOESN’T LEAD TO A
CHANGE IN UPPER & LOWER ENERGY LEVEL
 NUCLEI IN THE UPPER STATE STARTS TO
TRANSFER ITS ENERGY TO A NUCLEI IN
LOWER ENERGY LEVEL.

CHEMICAL SHIFT
 CHEMICAL SHIFT
the chemical shift is the resonant frequency of an
atomic nucleus relative to a standard in a magnetic
field.
 FACTORS INFLUENCING CHEMICAL
SHIFT
1. ELECTRONEGATIVITY -SHIELDlNG AND
DESHIELDING
2. VAN DER WAALS DESHIELDING
3. ANISOTROPIC EFFECTS

NMR SPECTROSCOPY.pptx

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