7.3.4
Hydrogen-1 NMR 2
Making Spectra Clear
Making Spectra Clear
The choice of solvent before the spectra is recorded makes the process easier. The process of integration after also makes interpretation of the spectra easier.


Solvent choice
Solvent choice
- The solvent choice in 1H NMR is crucial because many solvents contain 1H's.
- If a solvent contains 1H's, they will appear in the spectrum and this will cause confusion.
- This can be solved by using solvents without any 1H's (e.g. CCl4) or deuterated solvents (e.g. CDCl3, D2O).


Deuterated solvents
Deuterated solvents
- Deuterated solvents are the same as many protonated solvents but each 1H has been replaced by a deuterium (2D) atom.
- Deuterium atoms have an even nucleon number and so will not interfere with the NMR.


Integration
Integration
- The area ratios of signals in spectra are hard to evaluate at first glance when signal splitting happens.
- E.g. It is hard to compare the area ratio under a quartet and a singlet.
- To make it easier, many NMR machines integrate the peaks to then give an accurate ratio.
Examples of 1H NMR
Examples of 1H NMR
Below are some examples to demonstrate interpreting 1H NMR spectra.


Example 1: 1,1-dichloroethane
Example 1: 1,1-dichloroethane
- The spectrum is shown above and the interpretation is on the next slide.


Example 1: 1,1-dichloroethane
Example 1: 1,1-dichloroethane
- The spectrum shows two peaks representing the two different proton environments.
- The peak on the left represents the 1H on the -CCl2H because it is deshielded.
- It is a quartet because the adjacent carbon has three protons attached.


Example 2: Bromo-dimethyl ether
Example 2: Bromo-dimethyl ether
- The spectrum is shown above and the interpretation is on the next slide.


Example 2: Bromo-dimethyl ether
Example 2: Bromo-dimethyl ether
- The spectrum shows two peaks representing the two different proton environments.
- Both peaks are singlets because neither of them are adjacent to any carbons with any protons.


Example 3: Ethanol
Example 3: Ethanol
- The spectrum is shown above and the interpretation is on the next slide.


Example 3: Ethanol
Example 3: Ethanol
- The spectrum shows two peaks representing the two different proton environments.
- The peak on the left represents the 1Hs on the -CH2OH because it is deshielded.
- The splittings are a triplet and a quartet as expected.
1Structure - Models of the Particulate of Matter
1.1Introduction to the Particulate Model of Matter
1.2The Nuclear Atom
1.3Electron Configuration
1.4Counting Particles by Mass: The Mole
1.6Elements, Compounds & Mixtures
1.7States of Matter & Changes of State
1.8Reacting Masses &. Volumes
1.9Solutions
2Structure - Models of Bonding & Structure
2.1The Ionic Model
2.2The Covalent Model
2.3Covalent Structures
2.4The Metallic Model
2.5From Models to Materials
2.6Valence Electrons & Ionic Compounds
2.7Molecular Shape
3Structure - Classification of Matter
3.1The Periodic Table: Classification of Elements
3.2Periodic Trends
3.3Group 1 Alkali Metals
3.4Halogens
3.5Noble gases, group 18
3.6Functional Groups: Classification of Organic
3.7Functional Group Chemistry
3.8Alkanes
3.9Alcohols
4Reactivity - What Drives Chemical Reaction?
4.1Endothermic & Exothermic Reactions
4.2Enthalpy of Reaction, Formation, & Hess' Law
5Reactivity - How Much, How Fast & How Far?
5.1Kinetics
5.2Rates of Reaction
5.3Stoichometry
5.4Le Châtelier’s Principle
5.5Introduction to Equilibrium
5.6Equilibrium Constant
5.7Reaction Quotient & Equilibrium Constant
6Reactivity - The Mechanisms of Chemical Change
6.1Proton Transfer Reactions
6.2The pH Scale
6.3Strong & Weak Acids and Bases
6.4Acid Deposition
6.5Types of Organic Reactions
6.6Oxidation & Reduction
6.7Electrochemical Cells
6.9Acid-Base Titrations
6.9.1Titration Calculation Weak Acid & Strong Base
6.9.2Titration Experimental Detail
6.9.3Extended Response - Titration
6.9.4Titration Calculations
6.9.5Titration Curves
6.9.6Titration Calculation Strong Acid & Weak Base
6.9.7IB Multiple Choice - Titrations
6.9.8Polyprotic Acids
6.9.9Titration Calculations Strong Acid & Strong Base
6.9.10Titrations Curves 2
7Measurement, Data Processing & Analysis
7.1Uncertainties & Errors in Measurements & Results
7.2Graphical Techniques
7.3Spectroscopic Identification of Organic Compounds
7.4Infrared Spectroscpy
Jump to other topics
1Structure - Models of the Particulate of Matter
1.1Introduction to the Particulate Model of Matter
1.2The Nuclear Atom
1.3Electron Configuration
1.4Counting Particles by Mass: The Mole
1.6Elements, Compounds & Mixtures
1.7States of Matter & Changes of State
1.8Reacting Masses &. Volumes
1.9Solutions
2Structure - Models of Bonding & Structure
2.1The Ionic Model
2.2The Covalent Model
2.3Covalent Structures
2.4The Metallic Model
2.5From Models to Materials
2.6Valence Electrons & Ionic Compounds
2.7Molecular Shape
3Structure - Classification of Matter
3.1The Periodic Table: Classification of Elements
3.2Periodic Trends
3.3Group 1 Alkali Metals
3.4Halogens
3.5Noble gases, group 18
3.6Functional Groups: Classification of Organic
3.7Functional Group Chemistry
3.8Alkanes
3.9Alcohols
4Reactivity - What Drives Chemical Reaction?
4.1Endothermic & Exothermic Reactions
4.2Enthalpy of Reaction, Formation, & Hess' Law
5Reactivity - How Much, How Fast & How Far?
5.1Kinetics
5.2Rates of Reaction
5.3Stoichometry
5.4Le Châtelier’s Principle
5.5Introduction to Equilibrium
5.6Equilibrium Constant
5.7Reaction Quotient & Equilibrium Constant
6Reactivity - The Mechanisms of Chemical Change
6.1Proton Transfer Reactions
6.2The pH Scale
6.3Strong & Weak Acids and Bases
6.4Acid Deposition
6.5Types of Organic Reactions
6.6Oxidation & Reduction
6.7Electrochemical Cells
6.9Acid-Base Titrations
6.9.1Titration Calculation Weak Acid & Strong Base
6.9.2Titration Experimental Detail
6.9.3Extended Response - Titration
6.9.4Titration Calculations
6.9.5Titration Curves
6.9.6Titration Calculation Strong Acid & Weak Base
6.9.7IB Multiple Choice - Titrations
6.9.8Polyprotic Acids
6.9.9Titration Calculations Strong Acid & Strong Base
6.9.10Titrations Curves 2
7Measurement, Data Processing & Analysis
7.1Uncertainties & Errors in Measurements & Results
7.2Graphical Techniques
7.3Spectroscopic Identification of Organic Compounds
7.4Infrared Spectroscpy
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