Home

Chemistry

Analysis

Proton NMR spectroscopy

Select Lesson

Exam Board

Select an option

Practical skills

The scientific method

How to plan experiments

Improving repeatability and reproducibility

Presenting results using tables and graphs

Analysing results: anomalies and correlation

Evaluating experiments

Modern analytical techniques II

NMR spectroscopy

Proton NMR spectroscopy

Chromatography

Combining analytical techniques

Organic chemistry III

Benzene: structure and combustion

Electrophilic substitution

Friedel-Crafts reactions

Phenols

Aliphatic and aromatic amines

Reactions of amines

Forming amides

Condensation polymers

Amino acids and zwitterions

Grignard reagents

Synthetic routes

Practical techniques

Percentage composition and combustion analysis

Organic chemistry II

Optical isomers and chirality

Aldehydes and ketones

Carboxylic acids: properties and reactions

Esters: formation, properties and uses

Acyl chlorides: formation and reactions

Kinetics II

Measuring rates of reaction

Determining reaction orders

The initial rates method

Rate equations and the rate constant

The rate determining step

Halogenoalkane reaction mechanisms

Activation energy and the Arrhenius equation

Transition metals

Transition metals: electron configuration and oxidation number

Complex ions: formation, shape and isomerism

Colours of inorganic ions and complexes

Chromium and its reactions

Ligand substitution reactions

Transition metals as catalysts

Redox II

Electrochemical cells and redox

Electrode potentials and calculations

The electrochemical series

Energy storage cells and hydrogen fuel cells

Redox titrations

Energetics II

Lattice enthalpies and Born-Haber cycles

Polarisation and the Pauling scale

Enthalpy change in solution

Entropy and calculating entropy change

Gibbs free energy change

Acid-base equilibria

Acids and bases

pH calculations

The ionic product of water

pH curves and indicators

Buffer solutions and calculations

Equilibrium II

The equilibrium constant

Partial pressure and gas equilibria

Le Chatelier's principle and equilibrium constants

Equilibrium I

Reversible reactions

Le Chatelier's principle

Kinetics I

Collision theory and rates of reaction

Calculating the rate of reaction

Catalysts and the Maxwell-Boltzmann distribution

Energetics I

Enthalpy changes and reaction profiles

Standard enthalpy changes

Hess's Law and enthalpy cycles

Calculating bond enthalpies

Modern analytical techniques I

Mass spectrometry

IR spectroscopy

Organic chemistry I

Basic concepts of organic chemistry

Organic reactions and mechanisms

Structural isomerism

Alkanes and free radical substitution

Fractional distillation of crude oil

Fuels: combustion and emissions

Alkenes: bonding and reactivity

Stereoisomerism

Reactions of alkenes

Addition polymerisation

Halogenoalkanes and their reactions

Alcohol: classification and reactions

Oxidation of alcohols

Organic techniques

Formulae, equations and amounts of substances

The mole and Avogadro's constant

Calculations involving gases

Empirical and molecular formulae

Balancing equations

Acid-base titrations

Calculating uncertainty and errors

Atom economy and percentage yield

Inorganic chemistry and the periodic table

Group 2: ionisation energy and properties

Thermal stability of nitrates and carbonates

Chemical properties of Group 7

Reactions with halogens

Halide ion reactions

Testing for ions

Redox I

Calculating oxidation numbers

Oxidation, reduction and redox reactions

Bonding and structure

Ionic bonding

Covalent bonding

Shapes of molecules

Giant covalent and metallic structures

Electronegativity and polarisation

Intermolecular forces: types and examples

Hydrogen bonding

Solubility

Predicting structures and properties

Atomic structure and the periodic table

The atom: history, structure and isotopes

Relative masses and mass spectrometry

Electronic structure: shells and orbitals

Atomic emission spectra

Ionisation energies

Ionisation energy trends

Periodicity

Explainer Video

Tutor: Alexander

Summary

Proton NMR spectroscopy

In a nutshell

Proton NMR utilises the odd number of nucleons in the hydrogen nuclei to measure their absorption at different frequencies. Splitting is a feature of proton NMR which can tell you the number of hydrogen atoms on an adjacent carbon.

$^1H$ NMR

Proton nuclear magnetic resonance (NMR) is how hydrogen nuclei, protons, react in a magnetic field. Each peak on a $^1H$ spectrum represents a hydrogen environment. The number above the peak gives the ratio of the area under the peaks. This shows the relative number of hydrogens present in the hydrogen environment. They are given as ratios. This is because they show the relative number of hydrogens, not the total amount.

Splitting patterns

Splitting patterns are a feature of high-resolution proton NMR. The splitting pattern of each peak is determined by the number of protons on adjacent carbon atoms.

$Splitting\ =\ n\ +\ 1$ ; where $n$ is the number of protons on adjacent carbon atoms.

Number of proton on adjacent carbon	Splitting pattern	splitting pattern ratio	Shape
$0$	$1$ , singlet	$1$
$1$	$2$ , doublet	$1:1$
$2$	$3$ , triplet	$1:2:1$
$3$	$4$ , quartet	$1:3:3:1$

Splitting pattern	Example	Explanation
Singlet		For the proton $H_A$ , there are no protons on the adjacent carbon atom, so a singlet it produced.
Doublet		For the proton $H_A$ , there is one proton ( $H_B$ ) on the adjacent carbon atom, so a doublet is produced.
Triplet		For the proton $H_A$ , there are two protons ( $H_B$ ) on the adjacent carbon atom, so a triplet is produced.
Quartet		For the proton $H_A$ , there are three protons ( $H_B$ ) on the adjacent carbon atom, so a quartet is produced.

Integration traces

Integration traces show the area under the peaks more clearly. This shows the number of hydrogens in a particular environment using an integration line.


There are two hydrogens in environment a and three hydrogens in environment b, so the integration trace shows their areas in the ratio $2:3$ .	There are six hydrogens in environment a and one hydrogen in environemnt b, so the integration trace shows their areas in the ratio $6:1$ .

Hydrogen-free solvents

In proton NMR, if a sample has to be dissolved, it can not be done in a solvent which contains $^1H$ atoms, as they would appear on the spectra. This will make it difficult to distinguish specific peaks.

Deuterated solvents are often used. Hydrogen atoms in water have been replaced by deuterium $(D$ or $^2H)$ . This doesn't show up on the NMR spectra as it has an even number of nucleons (one proton and one neutron), unlike water which only has one proton. $CCl_4$ can also be used.

$^1H$ Chemical shifts

To correspond to each peak in an NMR spectrum with a hydrogen environment, a table with the chemical shifts and hydrogen environments is provided. Hydrogen environments can overlap which can mean that matching peaks to chemical shifts may not always be easy.

$^1H$ NMR CHEMICAL shifts relative to (SOLVENt)

Chemical shift

\delta

(ppm)

Hydrogen environment

Example

0.5-5.5

Alcohol

R-O\textbf{H}

0.9-1.7

Alkane

-C\textbf{H}_3, -C\textbf{H}_2,-C\textbf{H}

2.0-3.0

Alkyl next to

C=O

O=C-C\textbf{H}

2.3-3.0

Alkyl next to aromatic ring

$\textbf{H}_3C-Ar$ 

2.3-3.0

Hydrogen on alkyl amine

R-C\textbf{H}-N, R-C\textbf{H}_2,N-C\textbf{H}_3

3.0-5.0

Aryl amine

Ar-C\textbf{H}_2NH_2, Ar-C\textbf{H}RNH_2

3.2-4.2

Alkyl next to a halogen

X-C\textbf{H}_2

4.5-6.0

Alkene

R=C\textbf{H}_2

4.5-10.0

Phenol, phenylamine

$\textbf{H}O-Ar, Ar-N\textbf{H}_2$ 

5.0-12.0

Amide

RCON\textbf{H}R, RCON\textbf{H}_2R

6.0-8.5

Aromatic ring

Ar-\textbf{H}

9.0-10.0

Aldehyde

R-C\textbf{H}O

9.0-12.0

Carboxylic acid

R-COO\textbf{H}

Learn with Basics

Length:

Unit 1

NMR spectroscopy

Jump Ahead

Optional

Unit 2

Proton NMR spectroscopy

Final Test

Create an account to complete the exercises

FAQs - Frequently Asked Questions

What is peak splitting?

Peak splitting is the splitting of proton peaks which shows the number of hydrogens on adjacent carbon atoms.

What is the difference between proton NMR and carbon NMR?

Proton NMR looks at the hydrogen environments and the amount of protons whilst carbon NMR looks at the carbon environments and the amount of carbons.

What is proton NMR used for?

Proton NMR is a spectroscopic technique which can help identify or confirm the structure of organic compounds or those that contain protons.

Home

Chemistry

Analysis

Proton NMR spectroscopy

Videos

Summary

Exercises

Select Lesson

Exam Board

Select an option

Practical skills

The scientific method

How to plan experiments

Improving repeatability and reproducibility

Presenting results using tables and graphs

Analysing results: anomalies and correlation

Evaluating experiments

Modern analytical techniques II

NMR spectroscopy

Proton NMR spectroscopy

Chromatography

Combining analytical techniques

Organic chemistry III

Benzene: structure and combustion

Electrophilic substitution

Friedel-Crafts reactions

Phenols

Aliphatic and aromatic amines

Reactions of amines

Forming amides

Condensation polymers

Amino acids and zwitterions

Grignard reagents

Synthetic routes

Practical techniques

Percentage composition and combustion analysis

Organic chemistry II

Optical isomers and chirality

Aldehydes and ketones

Carboxylic acids: properties and reactions

Esters: formation, properties and uses

Acyl chlorides: formation and reactions

Kinetics II

Measuring rates of reaction

Determining reaction orders

The initial rates method

Rate equations and the rate constant

The rate determining step

Halogenoalkane reaction mechanisms

Activation energy and the Arrhenius equation

Transition metals

Transition metals: electron configuration and oxidation number

Complex ions: formation, shape and isomerism

Colours of inorganic ions and complexes

Chromium and its reactions

Ligand substitution reactions

Transition metals as catalysts

Redox II

Electrochemical cells and redox

Electrode potentials and calculations

The electrochemical series

Energy storage cells and hydrogen fuel cells

Redox titrations

Energetics II

Lattice enthalpies and Born-Haber cycles

Polarisation and the Pauling scale

Enthalpy change in solution

Entropy and calculating entropy change

Gibbs free energy change

Acid-base equilibria

Acids and bases

pH calculations

The ionic product of water

pH curves and indicators

Buffer solutions and calculations

Equilibrium II

The equilibrium constant

Partial pressure and gas equilibria

Le Chatelier's principle and equilibrium constants

Equilibrium I

Reversible reactions

Le Chatelier's principle

Kinetics I

Collision theory and rates of reaction

Calculating the rate of reaction

Catalysts and the Maxwell-Boltzmann distribution

Energetics I

Enthalpy changes and reaction profiles

Standard enthalpy changes

Hess's Law and enthalpy cycles

Calculating bond enthalpies

Modern analytical techniques I

Mass spectrometry

IR spectroscopy

Organic chemistry I

Basic concepts of organic chemistry

Organic reactions and mechanisms

Structural isomerism

Alkanes and free radical substitution

Fractional distillation of crude oil

Fuels: combustion and emissions

Alkenes: bonding and reactivity

Stereoisomerism

Reactions of alkenes

Addition polymerisation

Halogenoalkanes and their reactions

Alcohol: classification and reactions

Oxidation of alcohols

Organic techniques

Formulae, equations and amounts of substances

The mole and Avogadro's constant

Calculations involving gases

Empirical and molecular formulae

Balancing equations

Acid-base titrations

Calculating uncertainty and errors

Atom economy and percentage yield

Inorganic chemistry and the periodic table

Group 2: ionisation energy and properties

Thermal stability of nitrates and carbonates

Chemical properties of Group 7

Reactions with halogens

Halide ion reactions

Testing for ions

Redox I

Calculating oxidation numbers

Oxidation, reduction and redox reactions

Bonding and structure

Ionic bonding

Covalent bonding

Shapes of molecules

Giant covalent and metallic structures

Electronegativity and polarisation

Intermolecular forces: types and examples

Hydrogen bonding

Solubility

Predicting structures and properties

Atomic structure and the periodic table

The atom: history, structure and isotopes

Relative masses and mass spectrometry

Electronic structure: shells and orbitals

Atomic emission spectra

Ionisation energies

Ionisation energy trends

Periodicity

Explainer Video

Tutor: Alexander

Summary

Proton NMR spectroscopy

In a nutshell

$^1H$ NMR

Splitting patterns

Splitting patterns are a feature of high-resolution proton NMR. The splitting pattern of each peak is determined by the number of protons on adjacent carbon atoms.

$Splitting\ =\ n\ +\ 1$ ; where $n$ is the number of protons on adjacent carbon atoms.

Number of proton on adjacent carbon	Splitting pattern	splitting pattern ratio	Shape
$0$	$1$ , singlet	$1$
$1$	$2$ , doublet	$1:1$
$2$	$3$ , triplet	$1:2:1$
$3$	$4$ , quartet	$1:3:3:1$

Splitting pattern	Example	Explanation
Singlet		For the proton $H_A$ , there are no protons on the adjacent carbon atom, so a singlet it produced.
Doublet		For the proton $H_A$ , there is one proton ( $H_B$ ) on the adjacent carbon atom, so a doublet is produced.
Triplet		For the proton $H_A$ , there are two protons ( $H_B$ ) on the adjacent carbon atom, so a triplet is produced.
Quartet		For the proton $H_A$ , there are three protons ( $H_B$ ) on the adjacent carbon atom, so a quartet is produced.

Integration traces

Integration traces show the area under the peaks more clearly. This shows the number of hydrogens in a particular environment using an integration line.


There are two hydrogens in environment a and three hydrogens in environment b, so the integration trace shows their areas in the ratio $2:3$ .	There are six hydrogens in environment a and one hydrogen in environemnt b, so the integration trace shows their areas in the ratio $6:1$ .

Hydrogen-free solvents

$^1H$ Chemical shifts

$^1H$ NMR CHEMICAL shifts relative to (SOLVENt)

Chemical shift

\delta

(ppm)

Hydrogen environment

Example

0.5-5.5

Alcohol

R-O\textbf{H}

0.9-1.7

Alkane

-C\textbf{H}_3, -C\textbf{H}_2,-C\textbf{H}

2.0-3.0

Alkyl next to

C=O

O=C-C\textbf{H}

2.3-3.0

Alkyl next to aromatic ring

$\textbf{H}_3C-Ar$ 

2.3-3.0

Hydrogen on alkyl amine

R-C\textbf{H}-N, R-C\textbf{H}_2,N-C\textbf{H}_3

3.0-5.0

Aryl amine

Ar-C\textbf{H}_2NH_2, Ar-C\textbf{H}RNH_2

3.2-4.2

Alkyl next to a halogen

X-C\textbf{H}_2

4.5-6.0

Alkene

R=C\textbf{H}_2

4.5-10.0

Phenol, phenylamine

$\textbf{H}O-Ar, Ar-N\textbf{H}_2$ 

5.0-12.0

Amide

RCON\textbf{H}R, RCON\textbf{H}_2R

6.0-8.5

Aromatic ring

Ar-\textbf{H}

9.0-10.0

Aldehyde

R-C\textbf{H}O

9.0-12.0

Carboxylic acid

R-COO\textbf{H}

Learn with Basics

Length:

Unit 1

NMR spectroscopy

Jump Ahead

Optional

Unit 2

Proton NMR spectroscopy

Final Test

Create an account to complete the exercises

FAQs - Frequently Asked Questions

What is peak splitting?

Peak splitting is the splitting of proton peaks which shows the number of hydrogens on adjacent carbon atoms.

What is the difference between proton NMR and carbon NMR?

Proton NMR looks at the hydrogen environments and the amount of protons whilst carbon NMR looks at the carbon environments and the amount of carbons.

What is proton NMR used for?

Proton NMR is a spectroscopic technique which can help identify or confirm the structure of organic compounds or those that contain protons.

Proton NMR spectroscopy

Videos

Summary

Exercises

Select Lesson

Exam Board

Practical skills

Modern analytical techniques II

Organic chemistry III

Organic chemistry II

Kinetics II

Transition metals

Redox II

Energetics II

Acid-base equilibria

Equilibrium II

Equilibrium I

Kinetics I

Energetics I

Modern analytical techniques I

Organic chemistry I

Formulae, equations and amounts of substances

Inorganic chemistry and the periodic table

Redox I

Bonding and structure

Atomic structure and the periodic table

Explainer Video

Summary

Proton NMR spectroscopy

In a nutshell

1H^1H1H NMR

Splitting patterns

Number of proton on adjacent carbon

Splitting pattern

splitting pattern ratio

Shape​​

Splitting pattern

Example

Explanation

Integration traces

Hydrogen-free solvents

​1H^1H1H Chemical shifts​

1H^1H1H NMR CHEMICAL shifts relative to (SOLVENt)​

Chemical shift

(ppm)

Hydrogen environment

Example

Learn with Basics

Unit 1

NMR spectroscopy

Jump Ahead

Unit 2

Proton NMR spectroscopy

Final Test

FAQs - Frequently Asked Questions

What is peak splitting?

What is the difference between proton NMR and carbon NMR?

What is proton NMR used for?

Proton NMR spectroscopy

Videos

Summary

Exercises

Select Lesson

Exam Board

Practical skills

Modern analytical techniques II

Organic chemistry III

Organic chemistry II

Kinetics II

Transition metals

Redox II

Energetics II

Acid-base equilibria

Equilibrium II

Equilibrium I

Kinetics I

Energetics I

Modern analytical techniques I

Organic chemistry I

Formulae, equations and amounts of substances

$^1H$ NMR

Shape

$^1H$ Chemical shifts

$^1H$ NMR CHEMICAL shifts relative to (SOLVENt)

$^1H$ NMR

Shape

$^1H$ Chemical shifts

$^1H$ NMR CHEMICAL shifts relative to (SOLVENt)