Nuclear magnetic resonance (NMR) spectroscopy

CONTENTS
•SPECTROSCOPY
•NMR SPECTROSCOPY
•HISTORY
•THEORY
•PRINCIPLE
•INSTRUMENTATION
•SOLVENTS USED IN
NMR(PROTON NMR)
•CHEMICAL SHIFT
•FACTORS AFFECTING
CHEMICAL SHIFT
•RELAXATION PROCESS
27-12-2019V.K. VIKRAM VARMA 2

CONTD.
•SPIN-SPIN COUPLING
• 𝑛 + 1 RULE
•NMR SIGNALS IN VARIOUS
COMPOUNDS
•COUPLING CONSTANT
•NUCLEAR MAGNETIC
DOUBLE RESONANCE/ SPIN
DECOUPLING
•FT-NMR
•ADVANTAGES &
DISADVANTAGES
•APPLICATIONS
•REFERENCE

SPECTROSCOPY
•SPECTROSCOPY IS DEFINED AS THE INTERACTION
BETWEEN MATTER & ELECTROMAGNETIC
RADIATION(EMR) OR LIGHT.

CONTD.
•SPECTROMETRY IS THE APPLICATION OF
SPECTROSCOPY SO THAT THERE ARE QUANTIFIABLE
RESULTS THAT CAN THAN BE ASSESSED.
•SPECTROPHOTOMETER OR SPECTROMETER: THE
INSTRUMENT THAT IS USED TO MEASURE THE
AMOUNT OF ELECTRO MAGNETIC RADIATION
ABSORBED BY AN ORGANIC MOLECULE.

NMR SPECTROSCOPY
•NMR IS BASED ON THE ABSORPTION OF ELECTROMAGNETIC
RADIATION IN THE RADIO FREQUENCY REGION 4-900𝑀𝐻𝑧 BY
NUCLEI OF THE ATOMS.
•PROTON IS PRESENT IN THE NUCLEI & PROTON SHOWS SPIN
MOMENT DUE TO THIS SPIN PROTON ACTS AS SMALL MAGNET.
•NMR ACTIVE COMPOUNDS: 1
1
𝐻, 6
13
𝐶, 7
14
𝑁, 8
17
𝑂, 9
19
𝐹, 15
31
𝑃, 17
35
𝐶𝑙
•NMR INACTIVE COMPOUNDS: 6
12
𝐶, 8
16
𝑂

NMR

HISTORY
1937 Rabi’s prediction & observation of NMR
1946 Discovery of NMR by Bloch (Stanford) & Purcell (Harvard)
1948 Russel Varian files patent for Earth’s-field NMR
magnetometer
1952 Russel Varian files patent for Earth’s-field NMR well logging
1953 Over Hauser NOE (nuclear Over Hauser effect)
1966 Ernst, Anderson Fourier transform NMR
1975 Jeener, Ernst 2D NMR

CONTD.
1984 Nicholson NMR metabolomics
1985 Wuthrich first solution structure of a small protein (BPTI)
from NOE derived distance restraints
1987 3D NMR+ .
13
𝐶, .
15
𝑁 isotope labelling of recombinant proteins
1990 Pulsed field gradients
1996/7 Residual dipolar couplings (RDC) from partial alignment in
liquid crystalline media
2000s Dynamic nuclear polarisation (DNP) to enhance NMR
sensitivity

NOBEL PRIZE PIONEERS
1944 Physics
Rabi (Columbia)
Resonance
method for
recording the
magnetic
properties of
atomic nuclei
1952 Physics Bloch
(Stanford), Purcell
(Harvard)
Development of new
methods for nuclear
magnetic precision
measurements &
discoveries in
connection
therewith.
1991 Chemistry
Ernst (ETH)
Development of
the methodology
of high resolution
NMR
spectroscopy
2002 Chemistry
Wuthrich (ETH)
Development of
NMR
spectroscopy for
determining the
3D- structure of
biological
macromolecules
in solution
2003 Medicine
Lauterbur
(University of
Illinois in Urbana),
Mansfield
(University of
Nottingham)
Discoveries
concerning
magnetic resonance
imaging

THEORY
•SPIN QUANTUM NUMBER(I) IS RELATED TO THE
ATOMIC MASS & ATOMIC NUMBER OF THE NUCLEUS.
•ELEMENTS WITH EITHER ODD MASS OR ODD ATOMIC
NUMBER HAVE THE PROPERTY OF NUCLEAR SPIN.

CONTD.
ATOMIC
MASS
ATOMIC
NUMBER
EXAMPLES
Half integer Odd Odd .
1 𝐻 1
2
Half integer Odd Even .
13 𝐶 1
2
Integer Even Odd .
2 𝐻 1
Zero Even Even .
12 𝐶 0
NMR
active
NMR
inactive

PRINCIPLE
•SPINNING NUCLEUS: THE
PROTON PRESENT IN THE
NUCLEUS IS SPINNING &
ACTS AS MAGNETIC BAR.

CONTD.
•EFFECT OF EXTERNAL
MAGNETIC FIELD:
PROTON WILL ALIGNED WITH
THE MAGNETIC FIELD (LOW
ENERGY & PARALLEL)
PROTON WILL OPPOSED THE
MAGNETIC FIELD (HIGH
ENERGY & ANTIPARALLEL)

CONTD.
• PRECESSIONAL MOTION: PROTON WILL BE
SHOWING PRECESSIONAL MOTION DUE TO
INTERACTION OF SPIN & GRAVITATIONAL
FORCE OF EARTH→ GYROSCOPIC MOTION.
• ENERGY OF REOREINTATION OF
MAGNETIC DIPOLE
∆𝑬 = 𝒉𝒗
WHERE,
𝒉 = 𝒑𝒍𝒂𝒏𝒌′ 𝒔 𝒄𝒐𝒏𝒔𝒕𝒂𝒏𝒕
𝒗 = 𝒇𝒓𝒆𝒒𝒖𝒆𝒏𝒄𝒚 𝒐𝒇 𝒓𝒂𝒅𝒊𝒂𝒕𝒊𝒐𝒏

CONTD.
•PRECESSIONAL FREQUENCY:
SPINNING FREQUENCY OF
PROTON WILL BE SAME
PRECESSIONAL FREQUENCY 𝛼
EXTERNAL MAGNETIC FIELD
𝒗 𝜶 𝑩 𝒐

CONTD.
•ENERGY TRANSITION:
IF PROTON’S PRECESSIONAL FREQUENCY WILL BE
EXACTLY SAME THEN ONLY IT WILL ABSORB RADIATION
(RADIO FREQUENCY) & RESONANCE TAKES PLACE WHICH
IS KNOWN AS NMR.
PROTON GOES TO LOW ENERGY LEVEL TO HIGH ENERGY
LEVEL.

CONTD.
•THE EMITTED RADIOFREQUENCY SIGNAL GIVE THE NMR
SPECTRUM OF THE CONCERED NUCLEUS.
THE EMITTED RADIOFREQUENCY IS DIRECTLY
PROPOTIONAL TO THE STRENGTH OF THE APPLIED
MAGNETIC FIELD.
𝑽 =
𝜸𝑩 𝒐
𝟐𝝅
Where,
𝐵𝑜 = External magnetic field
𝛾 = Magnetogyric ratio
(ratio between magnetic moment & angular moment)

NMR SPECTRUM
•PLOT OF NMR SIGNALS 𝑉𝑠
MAGNETIC FIELG
(FREQUENCY) IN
REFERENCE TO TMS.

INSTRUMENTATION

CONTD.
•SAMPLE HOLDER:
5𝑚𝑚 GLASS TUBE IS USED, WHICH CAN HOLD 0.4𝑚𝑙 LIQUID
SAMPLE.
MICROTUBES ARE USED FOR LOW VOLUMES.
•MAGNET:
ACCURACY & QUALITY OF THE INSTRUMENT IS DEPENDENT ON
ITS STRENGTH.
RESOLUTION INCREASES WITH INCREASE IN THE FIELD
STRENGTH.

CONTD.
THREE TYPES OF MAGNETS CAN BE USED
CONVENTIONAL MAGNET (30 − 60𝑀𝐻𝑧)
PERMANENT MAGNET (60,90, 100𝑀𝐻𝑧)
SUPER CONDUCTING MAGNET (470𝑀𝐻𝑧)
RELATIONSHIP BETWEEN 𝐵𝑜& 𝑣 CALCULATED BY (ARMOUR
EQUATION)
𝒗 =
𝜸
𝟐𝝅
𝑩 𝒐
•SWEEP GENERATOR: A SET OF SWEEP COIL IS LOCATED PARALLEL
TO THE MAGNET, WHICH ALLOWS THE MAGNETIC FIELD.

CONTD.
•RF TRANSMITTER: IT IS A PAIR OF COILS MOUNTED
PERPENDICULAR TO THE PATH OF FIELD & RECIEVER
COIL.
•RECIEVER COIL & AMPLIFIER: AMPLIFIES THE RECEIVED
EMR BY 105 TIMES.
•DETECTOR: DETECTS THE SIGNAL PRODUCED BY
RESONATING NUCLEI.

SOLVENTS USED IN NMR (PROTON
NMR)
• CHEMICALLY INERT
• SOLVENTS SHOULD BE MAGNETICALLY ISOTROPIC IN NATURE
• FREE FROM ANY HYDROGEN ATOM
• SOLVENT SHOULD BE ABLE TO DISSOLVE THE MOLECULA/ SAMPLE IN A
RESONABLE QUANTITY.
• COMMONLY USED SOLVENTS:
CARBON TETRACHOLRIDE(𝐶𝐶𝑙4), CARBON DISULPHIDE(𝐶𝑆2),
DEUTEROCHLOROFORM(𝐶𝐷𝐶𝑙3), HEXACHLOROACETONE( 𝐶𝐷𝐶𝑙3 2 𝐶𝑂),
DEUTEROBENZENE(𝐶6 𝐷6), DEUTERODIMETHYLSULFOXIDE( 𝐶𝐻3 2 𝑆𝑂)

CONTD.
•HYDROGEN BONDING
INCREASE THE 𝛿 VALUE, & DESHIELDING OCCURS
HIGHER CONCENTRATION OF OH & NH GROUP LEADS
TO HYDROGEN BONDING & ELECTRON CLOUD
TRANSFER FROM HYDROGEN & ULTIMATELY
DESHIELDING TAKES PLACE.
 𝛿 VALUE OF SAME SAMPLE WILL BE DIFFERENT FOR
DIFFERENT SOLVENTS.

CHEMICAL SHIFT (DENOTED BY𝛿, 𝑝𝑝𝑚
UNITS)
•NUMBER OF SIGNAL & POSITION OF SIGNAL PLAYS VERY
IMPORTANT ROLE IN NMR.
•POSITION OF PROTONS HELPS US TO UNDERSTAND THE
NATURE OF PROTON IN COMPOUNDS.
•DIFFERENT TYPES OF PROTONS ARE PRESENT IN THE
COMPOUNDS & THEY HAVE DIFFERENT ELECTRONIC
ENVIRONMENT, PROTONS GET ABSORB AT DIFFERENT
APPLIED MAGNETIC FIELD.

CONTD.
•TMS (TETRAMETHYL SILANE)
REFERNCE COMPOUND
HIGH SHIELDING
MISCIBLE WITH ORGANIC
COMPOUND
HIGHLY VOLATILE
NOT TAKE PART IN CHEMICAL
NATURE

CONTD.
• ALIPHATIC, ALICYCLIC 𝛿 = 0 − 2
• 𝛽 −SUBSTITUTED ALIPHATIC 𝛿 = 1 − 2
• ALKYNE 𝛿 = 2 − 3
• 𝛼 −MONOSUBSTITUTED ALIPHATIC 𝛿 =
2 − 5
• 𝛼 −DESUBSTITUTED ALIPHATIC 𝛿 = 2.5 −
7
• ALKENE 𝛿 = 4.5 − 7.5
• AROMATIC & HETEROATOMIC 𝛿 = 6 − 9
• ALDEHYDE 𝛿 = 9 − 10

PROTON CHEMICAL SHIFTS

CONTD.

FACTORS AFFECTING CHEMICAL
SHIFT
• INDUCTIVE EFFECT(ELECTRONEGATIVITY):
GREATER THE ELECTRONEGATIVITY
GREATER IS THE DEDHIELDING
DELTA VALUE WILL BE MORE
• HYDROGEN BONDING:
• PROTONS THAT ARE INVVOLVED IN HYDROGEN BONDING ARE TYPICALLY
CHANGE THE CHEMICAL SHIFT VALUE.
• MORE HYDROGEN BONDING THE MORE PROTON IS DESHIELDED & CHEMICAL
SHIFT VALUE IS HIGHER.

CONTD.
•VANDERWALL DESHEILDING/ STERIC EFFECT:
ELECTRON CLOUD OF BULKY GROUP WILL REPEL THE
ELECTRON CLOUD OF PROTON DUE TO ELECTROSTATIC
REPULSION.
DESHIELDING→ INCREASED DELTA VALUE

CONTD.
•ANISOTROPIC(NON-UNIFORMITY) EFFECT:
CHEMICAL BONDS OF THE MOLECULES ARE ALSO HIGH
ELECTTRON DENSITY REGION & SETS OF MAGNETIC FIELD.
THESE FIELDS ARE STRONGER IN ONE DIRECTION THAN
OTHERS & KNOWNS AS ANISOTROPIC
CHEMICAL SHIFT OF THE NEAR BY NUCLEI IS DEPENDENT ON
THE ORIENTATION OF THE NUCLEUS WITH RESPECT TO BOND.

H-NMR SPECTRA 𝐶𝐻3 𝐵𝑟
E
X
A
M
P
L
E
S

ACETONE
E
X
A
M
P
L
E
S

METHYL ETHANOATE
E
X
A
M
P
L
E
S

TERTIARY BUTYL BROMIDE
E
X
A
M
P
L
E
S

1,1-DICHLOROETHANE
E
X
A
M
P
L
E
S

BROMOPROPANE
E
X
A
M
P
L
E
S

ISOPROPANOL
E
X
A
M
P
L
E
S

RELAXATION 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
FO THE PROPER MEASUREMENT & INTERPRETATION OF NMR
SPECTRA.

RELAXATION PROCESSSPIN LATTICE/
LONGITUDINAL
RELAXATION
•CHARACTERISED BY 𝑇1 NUCLEI
IN UPPER STATE STARTS TO
LOSE ENERGY TO THE
SURROUNDING.
SPIN-SPIN/ TRANSVERSE
RELAXATION
•CHARACTERISED BY 𝑇2 DOESN’T
LEAD TO A CHANGE IN UPPER &
LOWER ENERGY LEVEL.
A NUCLEI IN THE UPPER STATE
STARTS TO TRANSFER ITS
ENERGY TO A NUCLEI IN LOWER
ENERGY LEVEL.

SPIN-SPIN COUPLING
•WHEN SPIN OF 2 PROTONS ARE COUPLED, THEN IT IS
KNOWN AS SPIN-SPIN COUPLING.
•FOR SPIN-SPIN COUPLING MINIMUM 2 SETS OF
PROTONS ARE REQUIRED.
•DUE TO SPIN-SPIN COUPLING BETWEEN THE NEAR BY
PROTONS, SPLITTING OF SIGNAL WILL BE OBSERVED.

CONTD.

CONTD.
•IF NO PROTON IS PRESENT IN THE ADJACENT
CARBON THEN THAT SET OF PROTON WILL GIVE
SINGLET. E.G.𝐶𝐻3 𝐶𝐻2 𝐶𝑂𝐶𝐻3 (𝑆𝐼𝑁𝐺𝐿𝐸𝑇)
•PEAK INTENSITIES OF VARIOUS MULTIPLETS.

PASCAL’S TRIANGLE

𝑛 + 1 RULE:
•MULTIPLICITY OF SIGNAL IS CALCULATED BY USING 𝑛 + 1 RULE.
•ONE OF THE RULE TO PREDICT THE SPLITTING OF PROTON
SIGNALS. THIS IS CONSIDERED BY THE NEAR BY HYDROGEN
NUCLEI.
∴ 𝒏 = 𝑵𝒖𝒎𝒃𝒆𝒓 𝒐𝒇 𝒑𝒓𝒐𝒕𝒐𝒏𝒔 𝒊𝒏 𝒏𝒆𝒂𝒓𝒃𝒚 𝒏𝒖𝒄𝒍𝒆𝒊
𝒘𝒉𝒆𝒓𝒆,
𝒁𝒆𝒓𝒐 𝑯 𝒂𝒕𝒐𝒎 𝒂𝒔 𝒏𝒆𝒊𝒈𝒉𝒃𝒐𝒖𝒓 𝒏 + 𝟏 = 𝟎 + 𝟏 = 𝟏 𝑺𝒊𝒏𝒈𝒍𝒆𝒕
𝑶𝒏𝒆 𝑯 𝒂𝒕𝒐𝒎 𝒂𝒔 𝒏𝒆𝒊𝒈𝒉𝒃𝒐𝒖𝒓 𝒏 + 𝟏 = 𝟏 + 𝟏 = 𝟐 𝑫𝒐𝒖𝒃𝒍𝒆𝒕
𝑻𝒘𝒐 𝑯 𝒂𝒕𝒐𝒎 𝒂𝒔 𝒏𝒆𝒊𝒈𝒉𝒃𝒐𝒖𝒓 𝒏 + 𝟏 = 𝟐 + 𝟏 = 𝟑 𝑻𝒓𝒊𝒑𝒍𝒆𝒕

NMR SIGNALS IN VARIOUS
COMPOUNDS

CONTD.

COUPLING CONSTANT(J)
•THE DISTANCE BETWEEN THE CENTRES OF THE 2 ADJACENT
PEAKS IN A MULTIPLET IS CONSTANT & IT IS KNOWN AS
COUPLING CONSTANT.
•THE VALUE OF THE COUPLING CONSTANT IS INDEPENDENT
BECAUSE THERE IS NO EFFECT OF EXTERNAL/ APPLIED
MAGNETIC FIELD.
•IT IS USED TO DIFFERENTIATE BETWEEN TWO SINGLET &
ONE DOUBLET, TWO DOUBLET & ONE QUARTET.

CONTD.
•UNITS OF COUPLING CONSTANT IS 𝐻𝑧, 𝐶𝑦𝑐𝑙𝑒𝑠 𝑃𝑒𝑟 𝑆𝑒𝑐𝑜𝑛𝑑 (𝑐𝑝𝑠)
•GENERALLY VALUE OF COUPLING CONSTANT IS UPTO 20𝐻𝑧
•IT CAN BE
POSITIVE: IF THE ENERGY IS LOWER WHEN THE 2 NUCLEI
HAVE OPPOSITE SPIN
NEAGTIVE: IF THE ENERGY IS LOWER WHEN THE 2 NUCLEI
HAVE PARALLEL SPIN

CONTD.
•VALUE OF COUPLING
CONSTANT DEPENDS UPON
NUMBER OF COVALENT
BONDS
STRUCTURAL
RELATIONSHIP BETWEEN
THE COUPLE PROTONS

NUCLEAR MAGNETIC DOUBLE
RESONANCE/ SPIN DECOUPLING
•IT IS A TECHNIQUE WHICH INVOLVED IRRADIATION OF
PROTONS OR SET OF PROTONS; THIS IRRADIATION IS
DONE BY INTENSE RADIOFREQUENCY ENERGY.
•THE ENERGY ELIMINATES SPIN-SPIN COUPLING
AMONGST PROTONS.
•TWO RADIOFREQUENCY IS USED, SO KNOWN AS DOUBLE
RESONANCE.

CONTD.
•THIS TECHNIQUE IS A POWERFUL TOOL FOR
SIMPLYFYING THE SPECTRUM.

FT-NMR (FOURIER TRANSFORM
NMR)/ PULSE NMR• THE SAMPLE IS IRRADIATED PERIODICALLY WITH BRIEF, HGHLY INTENSE
PULSE OF RADIOFREQUENCY RADIATION, FOLLOWING WHICH THE FREE
INDUCTION DECAY SIGNAL (A CHARACTERTIC EMISSION SIGNAL STIMULATED
BY IRRADIATION) IS RECORDED AS A FUNCTION OF TIME..
• A MATHEMATICAL TECHNIQUE THAT RESOLVES A COMPLEX FID (FREE
INDUCTION DECAY) SIGNAL INTO THE INDIVIDUAL FRQUENCIES THAT ADD
TOGETHER TO MAKE IT.

FT-NMR INSTRUMENTATION

COMPONENTS OF FT-NMR
• THE CENTRAL COMPONENT OF THE INSTRUMENT IS A HIGHLY STABLE MAGNET
IN WHICH THE SAMPLE IS PLACED.
• THE SAMPLE IS SURROUNDED BY THE TRANSMITTER/RECEIVER COIL.
• A CRYSTAL CONTROLLED FREQUENCY SYNTHESIZER HAVING AN OUTPUT
FREQUENCY OF 𝑉𝑐 - PRODUCES RADIO-FREQUENCY RADIATION.
• THIS SIGNAL PASSES INTO A PULSE SWITCH & POWER AMPLIFIER, WHICH
CREATES AN - INTENSE & REPRODUCIBLE PULSE OF RF CURRENT IN THE
TRANSMITTER COIL.
• RESULTING SIGNAL IS PICKED UP BY THE SAME COIL WHICH NOW SERVES A AS -
RECEIVER.

CONTD.

CONTD.
• THE SIGNAL IS THEN AMPLIFIED & TRANSMITTED TO A PHASE SENSITIVE
DETECTOR.
• THE DETECTOR CIRCUITRY PRODUCED THE DIFFERENCE BETWEEN THE
NUCLEAR SIGNALS 𝑉𝑛 & THE CRYSTAL OSCILLATOR OUTPUT 𝑉𝑐 WHICH
LEADS TO THE LOW FREQUENCY TIME-DOMAIN SIGNAL.
• THIS SIGNAL IS DIGITALIZED & COLLECTED IN THE MEMORY OF THE
COMPUTER FOR ANALYSIS BY A FOURIER TRANSFORM PROGRAM &
OTHER DATA ANALYSIS SOFTWARE.
• THE OUTPUT FROM THIS PROGRAM IS PLOTTED GIVING A FREQUENCY
DOMAIN SPECTRUM.

ADVANTAGES OF FT-NMR
•MORE SENSITIVE & CAN MEASURE WEAKER SIGNALS
•PULSED FT-NMR IS MUCH FASTER COMPARE TO CONTINUOUS
WAVE NMR.
•READINGS CAN BE OBTAINED WITH LESS THAN 0.5𝑚𝑔 OF THE
COMPOUND.
•FT METHOD ALSO GIVES IMPROVED SPECTRA FOR SPARINGLY
SOLUBLE COMPOUNDS.

ADVANTAGES & DISADVANTAGES OF
NMR
ADVANTAGES
• ONLY FLUIDS ARE VISIBLE TO NMR
TECHNOLOGY SO POROSITY
MEASUREMENT IS INDEPENDENT
OF THE LITHOLOGY.
• A BETTER MESUREMENT OF
PERMEABILITY IS POSSIBLE THAN
TRADITIONAL PLOT.
• NON-DESTRUCTIVE
DISADVANTAGES
•EXPENSIVE
•SLOWER LOGGING SPEEDS

APPLICATIONS
•PHARMACEUTICAL SCIENCE:
STUDY PHARMACEUTICALS & DRUG METABOLISM
•CHEMISTRY:
DETERMINE MOLECULAR STRUCTURE OF DIFFERENT
COMPOUNDS
IDENTITY PRODUCTS OF CHEMICAL REACTIONS
•BIOLOGY
PROTEIN NMR
OBTAIN STRUCUTURAL INFORMATION ON COMPLEX PROTEINS

CONTD.
•MEDICINE:
MRI
INSIGHT INTO THE STRUCTURAL INFORMATION OF THE
HUMAN BODY
SHARP CONTRAST IN SOFT TISSUE
•ENZYMOLOGY:
TO STUDY THE BIOLOGICAL ACTIVITIES OF ENZYME
STUDY OF CONFORMATIONAL DYNAMIC PROCESS IN ENZYMES

REFERENCE
• INTRODUCTION TO SPECTROSCOPY BY PAVIA.
• A TEXTBOOK OF ORGANIC CHEMISTRY BY BAHL ARUN & BAHL B.S.
• HTTP://WWW.CHEM.UCALGARY.CA/COURSES/350/CAREY5TH/CH13/CH13-NMR-2B.H
• HTTPS://TEACHING.SHU.AC.UK/HWB/CHEMISTRY/TUTORIALS/MOLSPEC/NMR1.HTM
• HTTPS://ORGSPECTROSCOPYINT.BLOGSPOT.COM/P/BASIC-1D-NMR-SPECTRA-SMALL-
AND-SIMPLE.HTML
• HTTPS://EN.WIKIPEDIA.ORG/WIKI/NUCLEAR_MAGNETIC_RESONANCE
• WWW.YOUTUBE.COM
• WWW.SLIDESHARE.COM
• WWW.GOOGLE.COM

Nuclear magnetic resonance (NMR) spectroscopy

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