a -b Н d

Chemistry
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ISBN:9781305957404
Author:Steven S. Zumdahl, Susan A. Zumdahl, Donald J. DeCoste
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Chapter1: Chemical Foundations
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Problem 1RQ: Define and explain the differences between the following terms. a. law and theory b. theory and...
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**Characteristic NMR Chemical Shifts**

### Type of Hydrogen and Chemical Shifts

- **(CH₃)₄Si**: 0 (by definition)
- **RNH₂**: 0.5-5.0
- **ROH**: 0.5-5.0
- **R₂NH**: 1-3
- **RCH₃**: 0.8-1.2
- **R₂CH₂**: 1.2-1.6
- **R₃CH**: 1.4-1.8
- **R₂C=CR'CHR''**: 1.6-2.6
- **RC≡CH**: 2.0-3.0
- **ArCH₃**: 2.2-2.5
- **O  
  ROCH₃**: 3.1-3.8
- **O  
  ROCH₂R**: 3.3-3.9
- **RCH₂Br**: 3.4-3.6
- **RCH₂Cl**: 3.6-3.8
- **ROCOL₂R**: 3.7-4.0
- **RCHF₂**: 4.1-4.7
- **ArOH**: 4.5-4.7
- **R₂C=CH₂**: 4.6-4.8
- **O  
  ROCH**: 5-6.5
- **ArH**: 6.5-8.5
- **RCHO**: 9.5-10.1
- **RCOOH**: 10-13

*Values are relative to tetramethylsilane. Other atoms within the molecule may cause the signal to appear outside these ranges.*

---

### Characteristic ¹³C-NMR Chemical Shifts

#### Type of Carbon and Chemical Shifts

- **(CH₃)₄Si**: 0 (by definition)
- **(CH₃)₂C**: 0-40
- **RCH₂R**: 10-40
- **R₂CH₂**: 15-55
- **RCH₂X**:
Transcribed Image Text:**Characteristic NMR Chemical Shifts** ### Type of Hydrogen and Chemical Shifts - **(CH₃)₄Si**: 0 (by definition) - **RNH₂**: 0.5-5.0 - **ROH**: 0.5-5.0 - **R₂NH**: 1-3 - **RCH₃**: 0.8-1.2 - **R₂CH₂**: 1.2-1.6 - **R₃CH**: 1.4-1.8 - **R₂C=CR'CHR''**: 1.6-2.6 - **RC≡CH**: 2.0-3.0 - **ArCH₃**: 2.2-2.5 - **O ROCH₃**: 3.1-3.8 - **O ROCH₂R**: 3.3-3.9 - **RCH₂Br**: 3.4-3.6 - **RCH₂Cl**: 3.6-3.8 - **ROCOL₂R**: 3.7-4.0 - **RCHF₂**: 4.1-4.7 - **ArOH**: 4.5-4.7 - **R₂C=CH₂**: 4.6-4.8 - **O ROCH**: 5-6.5 - **ArH**: 6.5-8.5 - **RCHO**: 9.5-10.1 - **RCOOH**: 10-13 *Values are relative to tetramethylsilane. Other atoms within the molecule may cause the signal to appear outside these ranges.* --- ### Characteristic ¹³C-NMR Chemical Shifts #### Type of Carbon and Chemical Shifts - **(CH₃)₄Si**: 0 (by definition) - **(CH₃)₂C**: 0-40 - **RCH₂R**: 10-40 - **R₂CH₂**: 15-55 - **RCH₂X**:
### Molecular Structure and Chemical Shifts

#### Molecular Diagram:
The image showcases a molecular structure with various labeled atoms:

- **Position 'a':** Represents a carbon atom within a benzene ring.
- **Position 'b':** Represents a hydrogen atom also attached to a carbon in the benzene ring.
- **Position 'c':** Is a carbon atom in a carbonyl group (C=O).
- **Position 'd':** Is a hydrogen atom attached to the carbonyl group.

#### Chemical Shifts:

- **Carbon at Position 'a':**  
  - Chemical Shift Range: 110-160 ppm
  - Explanation: This range is typical for carbons in aromatic rings such as benzene.

- **Hydrogen at Position 'b':**  
  - Chemical Shift Range: 6.5-8.5 ppm
  - Explanation: Hydrogen atoms in aromatic rings typically resonate in this range due to the deshielding effects of the pi electrons.

- **Carbon at Position 'c':**  
  - Chemical Shift Range: 180-215 ppm
  - Explanation: Carbons in carbonyl groups exhibit shifts within this range because of the electron-withdrawing nature of the double-bonded oxygen.

- **Hydrogen at Position 'd':**  
  - Chemical Shift Range: 9.5-10.1 ppm
  - Explanation: This range is characteristic of hydrogen in aldehyde groups, reflecting the strong deshielding from the carbonyl group.

These chemical shift values are instrumental in identifying and analyzing functional groups in organic molecules using Nuclear Magnetic Resonance (NMR) spectroscopy.
Transcribed Image Text:### Molecular Structure and Chemical Shifts #### Molecular Diagram: The image showcases a molecular structure with various labeled atoms: - **Position 'a':** Represents a carbon atom within a benzene ring. - **Position 'b':** Represents a hydrogen atom also attached to a carbon in the benzene ring. - **Position 'c':** Is a carbon atom in a carbonyl group (C=O). - **Position 'd':** Is a hydrogen atom attached to the carbonyl group. #### Chemical Shifts: - **Carbon at Position 'a':** - Chemical Shift Range: 110-160 ppm - Explanation: This range is typical for carbons in aromatic rings such as benzene. - **Hydrogen at Position 'b':** - Chemical Shift Range: 6.5-8.5 ppm - Explanation: Hydrogen atoms in aromatic rings typically resonate in this range due to the deshielding effects of the pi electrons. - **Carbon at Position 'c':** - Chemical Shift Range: 180-215 ppm - Explanation: Carbons in carbonyl groups exhibit shifts within this range because of the electron-withdrawing nature of the double-bonded oxygen. - **Hydrogen at Position 'd':** - Chemical Shift Range: 9.5-10.1 ppm - Explanation: This range is characteristic of hydrogen in aldehyde groups, reflecting the strong deshielding from the carbonyl group. These chemical shift values are instrumental in identifying and analyzing functional groups in organic molecules using Nuclear Magnetic Resonance (NMR) spectroscopy.
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