The chemical shifts for each type of proton in the given compound have to be predicted. Concept Introduction: The chemical shift values of a methyl, a methylene and a methine group are given below. Chemical shift ( i n p p m ) Methyl group ∼ 0.9 Methylene group ∼ 1.2 Methine group ∼ 1.7 Presence of electron withdrawing atom or group next to these groups will move the chemical shift value towards downfield while presence of electron donating atom or group next to these groups will move the chemical shift value towards upfield. The inductive effect is distance dependent. The effect decreases with increasing distance. Both downfield and upfield are relative in manner. The left side of an NMR spectrum is described as downfield and the right side of it is known as upfield. These chemical shift values are modified by the presence of neighboring functional groups in the following way. Functional groups Effect on α protons Effect on β protons Oxygen of an alcohol or ether + 2.5 + 0.5 Oxygen of an ester + 3 + 0.6 Carbonyl groups + 1 + 0.2 Rules for identification of number of different protons: The number of signals in a proton NMR spectrum indicates the number of different types of protons. Chemically equivalent protons which are in identical chemical environment will produce only one signal. The two protons of a C H 2 group will be chemically equivalent if the compound lacks stereo centers. But if the compound has a stereo center, then the protons of a C H 2 group will not be chemically equivalent. Two C H 2 groups will be equivalent to each other if the C H 2 groups can be interchanged by either rotation or reflection. The above rule also applies for C H 3 groups or C H groups. The three protons of a C H 3 group are always chemically equivalent, even if there are stereo centers in the compound. Some important chemical shift values are given below. Type of proton Chemical shift ( δ ) Allylic ∼ 2 Alkynyl ∼ 2 .5 Aromatic methyl ∼ 2 .5 Alkyl halide 2-4 Alcohol 2-5 Vinylic 4 .5-6 .5 Aryl 6 .5-8 Aldehyde ∼ 10 Carboxylic acid ∼ 12

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Answer 1

Question

Chapter 3.2, Problem 3.19P

Interpretation Introduction

Interpretation:

The chemical shifts for each type of proton in the given compound have to be predicted.

Concept Introduction:

The chemical shift values of a methyl, a methylene and a methine group are given below.

Chemical shift (in ppm)
Methyl group ∼0.9
Methylene group ∼1.2
Methine group ∼1.7

Presence of electron withdrawing atom or group next to these groups will move the chemical shift value towards downfield while presence of electron donating atom or group next to these groups will move the chemical shift value towards upfield. The inductive effect is distance dependent. The effect decreases with increasing distance.

Both downfield and upfield are relative in manner. The left side of an NMR spectrum is described as downfield and the right side of it is known as upfield.

These chemical shift values are modified by the presence of neighboring functional groups in the following way.

Functional groups Effect on α protons Effect on β protons
Oxygen of an alcohol or ether +2.5 +0.5
Oxygen of an ester +3 +0.6
Carbonyl groups +1 +0.2

Rules for identification of number of different protons:

The number of signals in a proton NMR spectrum indicates the number of different types of protons. Chemically equivalent protons which are in identical chemical environment will produce only one signal.

The two protons of a CH2 group will be chemically equivalent if the compound lacks stereo centers. But if the compound has a stereo center, then the protons of a CH2 group will not be chemically equivalent.

Two CH2 groups will be equivalent to each other if the CH2 groups can be interchanged by either rotation or reflection.

The above rule also applies for CH3 groups or CH groups.

The three protons of a CH3 group are always chemically equivalent, even if there are stereo centers in the compound.

Some important chemical shift values are given below.

Type of proton Chemical shift (δ)
Allylic ∼2
Alkynyl ∼2.5
Aromatic methyl ∼2.5
Alkyl halide 2-4
Alcohol 2-5
Vinylic 4.5-6.5
Aryl 6.5-8
Aldehyde ∼10
Carboxylic acid ∼12

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Answer 2

Question

Chapter 3.2, Problem 3.19P

Interpretation Introduction

Interpretation:

The chemical shifts for each type of proton in the given compound have to be predicted.

Concept Introduction:

The chemical shift values of a methyl, a methylene and a methine group are given below.

Chemical shift (in ppm)
Methyl group ∼0.9
Methylene group ∼1.2
Methine group ∼1.7

Presence of electron withdrawing atom or group next to these groups will move the chemical shift value towards downfield while presence of electron donating atom or group next to these groups will move the chemical shift value towards upfield. The inductive effect is distance dependent. The effect decreases with increasing distance.

Both downfield and upfield are relative in manner. The left side of an NMR spectrum is described as downfield and the right side of it is known as upfield.

These chemical shift values are modified by the presence of neighboring functional groups in the following way.

Functional groups Effect on α protons Effect on β protons
Oxygen of an alcohol or ether +2.5 +0.5
Oxygen of an ester +3 +0.6
Carbonyl groups +1 +0.2

Rules for identification of number of different protons:

The number of signals in a proton NMR spectrum indicates the number of different types of protons. Chemically equivalent protons which are in identical chemical environment will produce only one signal.

The two protons of a CH2 group will be chemically equivalent if the compound lacks stereo centers. But if the compound has a stereo center, then the protons of a CH2 group will not be chemically equivalent.

Two CH2 groups will be equivalent to each other if the CH2 groups can be interchanged by either rotation or reflection.

The above rule also applies for CH3 groups or CH groups.

The three protons of a CH3 group are always chemically equivalent, even if there are stereo centers in the compound.

Some important chemical shift values are given below.

Type of proton Chemical shift (δ)
Allylic ∼2
Alkynyl ∼2.5
Aromatic methyl ∼2.5
Alkyl halide 2-4
Alcohol 2-5
Vinylic 4.5-6.5
Aryl 6.5-8
Aldehyde ∼10
Carboxylic acid ∼12

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Answer 3

Question

Chapter 3.2, Problem 3.19P

Interpretation Introduction

Interpretation:

The chemical shifts for each type of proton in the given compound have to be predicted.

Concept Introduction:

The chemical shift values of a methyl, a methylene and a methine group are given below.

Chemical shift (in ppm)
Methyl group ∼0.9
Methylene group ∼1.2
Methine group ∼1.7

Presence of electron withdrawing atom or group next to these groups will move the chemical shift value towards downfield while presence of electron donating atom or group next to these groups will move the chemical shift value towards upfield. The inductive effect is distance dependent. The effect decreases with increasing distance.

Both downfield and upfield are relative in manner. The left side of an NMR spectrum is described as downfield and the right side of it is known as upfield.

These chemical shift values are modified by the presence of neighboring functional groups in the following way.

Functional groups Effect on α protons Effect on β protons
Oxygen of an alcohol or ether +2.5 +0.5
Oxygen of an ester +3 +0.6
Carbonyl groups +1 +0.2

Rules for identification of number of different protons:

The number of signals in a proton NMR spectrum indicates the number of different types of protons. Chemically equivalent protons which are in identical chemical environment will produce only one signal.

The two protons of a CH2 group will be chemically equivalent if the compound lacks stereo centers. But if the compound has a stereo center, then the protons of a CH2 group will not be chemically equivalent.

Two CH2 groups will be equivalent to each other if the CH2 groups can be interchanged by either rotation or reflection.

The above rule also applies for CH3 groups or CH groups.

The three protons of a CH3 group are always chemically equivalent, even if there are stereo centers in the compound.

Some important chemical shift values are given below.

Type of proton Chemical shift (δ)
Allylic ∼2
Alkynyl ∼2.5
Aromatic methyl ∼2.5
Alkyl halide 2-4
Alcohol 2-5
Vinylic 4.5-6.5
Aryl 6.5-8
Aldehyde ∼10
Carboxylic acid ∼12

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Answer 4

Question

Chapter 3.2, Problem 3.19P

Interpretation Introduction

Interpretation:

The chemical shifts for each type of proton in the given compound have to be predicted.

Concept Introduction:

The chemical shift values of a methyl, a methylene and a methine group are given below.

Chemical shift (in ppm)
Methyl group ∼0.9
Methylene group ∼1.2
Methine group ∼1.7

Presence of electron withdrawing atom or group next to these groups will move the chemical shift value towards downfield while presence of electron donating atom or group next to these groups will move the chemical shift value towards upfield. The inductive effect is distance dependent. The effect decreases with increasing distance.

Both downfield and upfield are relative in manner. The left side of an NMR spectrum is described as downfield and the right side of it is known as upfield.

These chemical shift values are modified by the presence of neighboring functional groups in the following way.

Functional groups Effect on α protons Effect on β protons
Oxygen of an alcohol or ether +2.5 +0.5
Oxygen of an ester +3 +0.6
Carbonyl groups +1 +0.2

Rules for identification of number of different protons:

The number of signals in a proton NMR spectrum indicates the number of different types of protons. Chemically equivalent protons which are in identical chemical environment will produce only one signal.

The two protons of a CH2 group will be chemically equivalent if the compound lacks stereo centers. But if the compound has a stereo center, then the protons of a CH2 group will not be chemically equivalent.

Two CH2 groups will be equivalent to each other if the CH2 groups can be interchanged by either rotation or reflection.

The above rule also applies for CH3 groups or CH groups.

The three protons of a CH3 group are always chemically equivalent, even if there are stereo centers in the compound.

Some important chemical shift values are given below.

Type of proton Chemical shift (δ)
Allylic ∼2
Alkynyl ∼2.5
Aromatic methyl ∼2.5
Alkyl halide 2-4
Alcohol 2-5
Vinylic 4.5-6.5
Aryl 6.5-8
Aldehyde ∼10
Carboxylic acid ∼12

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Answer 5

Chapter 3.2, Problem 3.19P

Interpretation Introduction

Interpretation:

The chemical shifts for each type of proton in the given compound have to be predicted.

Concept Introduction:

The chemical shift values of a methyl, a methylene and a methine group are given below.

Chemical shift (in ppm)
Methyl group ∼0.9
Methylene group ∼1.2
Methine group ∼1.7

Presence of electron withdrawing atom or group next to these groups will move the chemical shift value towards downfield while presence of electron donating atom or group next to these groups will move the chemical shift value towards upfield. The inductive effect is distance dependent. The effect decreases with increasing distance.

Both downfield and upfield are relative in manner. The left side of an NMR spectrum is described as downfield and the right side of it is known as upfield.

These chemical shift values are modified by the presence of neighboring functional groups in the following way.

Functional groups Effect on α protons Effect on β protons
Oxygen of an alcohol or ether +2.5 +0.5
Oxygen of an ester +3 +0.6
Carbonyl groups +1 +0.2

Rules for identification of number of different protons:

The number of signals in a proton NMR spectrum indicates the number of different types of protons. Chemically equivalent protons which are in identical chemical environment will produce only one signal.

The two protons of a CH2 group will be chemically equivalent if the compound lacks stereo centers. But if the compound has a stereo center, then the protons of a CH2 group will not be chemically equivalent.

Two CH2 groups will be equivalent to each other if the CH2 groups can be interchanged by either rotation or reflection.

The above rule also applies for CH3 groups or CH groups.

The three protons of a CH3 group are always chemically equivalent, even if there are stereo centers in the compound.

Some important chemical shift values are given below.

Type of proton Chemical shift (δ)
Allylic ∼2
Alkynyl ∼2.5
Aromatic methyl ∼2.5
Alkyl halide 2-4
Alcohol 2-5
Vinylic 4.5-6.5
Aryl 6.5-8
Aldehyde ∼10
Carboxylic acid ∼12

Answer 6

Chapter 3.2, Problem 3.19P

Interpretation Introduction

Interpretation:

The chemical shifts for each type of proton in the given compound have to be predicted.

Concept Introduction:

The chemical shift values of a methyl, a methylene and a methine group are given below.

Chemical shift (in ppm)
Methyl group ∼0.9
Methylene group ∼1.2
Methine group ∼1.7

Presence of electron withdrawing atom or group next to these groups will move the chemical shift value towards downfield while presence of electron donating atom or group next to these groups will move the chemical shift value towards upfield. The inductive effect is distance dependent. The effect decreases with increasing distance.

Both downfield and upfield are relative in manner. The left side of an NMR spectrum is described as downfield and the right side of it is known as upfield.

These chemical shift values are modified by the presence of neighboring functional groups in the following way.

Functional groups Effect on α protons Effect on β protons
Oxygen of an alcohol or ether +2.5 +0.5
Oxygen of an ester +3 +0.6
Carbonyl groups +1 +0.2

Rules for identification of number of different protons:

The number of signals in a proton NMR spectrum indicates the number of different types of protons. Chemically equivalent protons which are in identical chemical environment will produce only one signal.

The two protons of a CH2 group will be chemically equivalent if the compound lacks stereo centers. But if the compound has a stereo center, then the protons of a CH2 group will not be chemically equivalent.

Two CH2 groups will be equivalent to each other if the CH2 groups can be interchanged by either rotation or reflection.

The above rule also applies for CH3 groups or CH groups.

The three protons of a CH3 group are always chemically equivalent, even if there are stereo centers in the compound.

Some important chemical shift values are given below.

Type of proton Chemical shift (δ)
Allylic ∼2
Alkynyl ∼2.5
Aromatic methyl ∼2.5
Alkyl halide 2-4
Alcohol 2-5
Vinylic 4.5-6.5
Aryl 6.5-8
Aldehyde ∼10
Carboxylic acid ∼12

Answer 7

Chapter 3.2, Problem 3.19P

Interpretation Introduction

Interpretation:

The chemical shifts for each type of proton in the given compound have to be predicted.

Concept Introduction:

The chemical shift values of a methyl, a methylene and a methine group are given below.

Chemical shift (in ppm)
Methyl group ∼0.9
Methylene group ∼1.2
Methine group ∼1.7

Presence of electron withdrawing atom or group next to these groups will move the chemical shift value towards downfield while presence of electron donating atom or group next to these groups will move the chemical shift value towards upfield. The inductive effect is distance dependent. The effect decreases with increasing distance.

Both downfield and upfield are relative in manner. The left side of an NMR spectrum is described as downfield and the right side of it is known as upfield.

These chemical shift values are modified by the presence of neighboring functional groups in the following way.

Functional groups Effect on α protons Effect on β protons
Oxygen of an alcohol or ether +2.5 +0.5
Oxygen of an ester +3 +0.6
Carbonyl groups +1 +0.2

Rules for identification of number of different protons:

The number of signals in a proton NMR spectrum indicates the number of different types of protons. Chemically equivalent protons which are in identical chemical environment will produce only one signal.

The two protons of a CH2 group will be chemically equivalent if the compound lacks stereo centers. But if the compound has a stereo center, then the protons of a CH2 group will not be chemically equivalent.

Two CH2 groups will be equivalent to each other if the CH2 groups can be interchanged by either rotation or reflection.

The above rule also applies for CH3 groups or CH groups.

The three protons of a CH3 group are always chemically equivalent, even if there are stereo centers in the compound.

Some important chemical shift values are given below.

Type of proton Chemical shift (δ)
Allylic ∼2
Alkynyl ∼2.5
Aromatic methyl ∼2.5
Alkyl halide 2-4
Alcohol 2-5
Vinylic 4.5-6.5
Aryl 6.5-8
Aldehyde ∼10
Carboxylic acid ∼12

Answer 8

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Answer 11

Ch. 3.1 - Prob. 3.2P Ch. 3.1 - Prob. 3.3P Ch. 3.1 - Prob. 3.4P Ch. 3.1 - Prob. 3.5P Ch. 3.1 - Prob. 3.6P Ch. 3.1 - Prob. 3.7P Ch. 3.1 - Prob. 3.8P Ch. 3.1 - Prob. 3.9P Ch. 3.1 - Prob. 3.10P Ch. 3.1 - If you look at your answers to the previous...

Solution Summary: The author explains that the chemical shifts for each type of proton in a given compound have to be predicted.

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Chapter 3 Solutions

	Chemical shift (in ppm)
Methyl group	∼0.9
Methylene group	∼1.2
Methine group	∼1.7

Functional groups	Effect on α protons	Effect on β protons
Oxygen of an alcohol or ether	+2.5	+0.5
Oxygen of an ester	+3	+0.6
Carbonyl groups	+1	+0.2

Type of proton	Chemical shift (δ)
Allylic	∼2
Alkynyl	∼2.5
Aromatic methyl	∼2.5
Alkyl halide	2-4
Alcohol	2-5
Vinylic	4.5-6.5
Aryl	6.5-8
Aldehyde	∼10
Carboxylic acid	∼12