Table of contents

1. A Review of General Chemistry5h 5m
2. Molecular Representations1h 14m
3. Acids and Bases2h 46m
4. Alkanes and Cycloalkanes4h 17m
5. Chirality3h 39m
6. Thermodynamics and Kinetics1h 22m
7. Substitution Reactions1h 48m
8. Elimination Reactions2h 30m
9. Alkenes and Alkynes2h 9m
10. Addition Reactions3h 19m
11. Radical Reactions1h 58m
12. Alcohols, Ethers, Epoxides and Thiols2h 42m
13. Alcohols and Carbonyl Compounds2h 17m
14. Synthetic Techniques1h 26m
15. Analytical Techniques:IR, NMR, Mass Spect7h 3m
16. Conjugated Systems6h 13m
17. Ultraviolet Spectroscopy51m
18. Aromaticity2h 34m
19. Reactions of Aromatics: EAS and Beyond5h 1m
20. Phenols55m
21. Aldehydes and Ketones: Nucleophilic Addition4h 56m
22. Carboxylic Acid Derivatives: NAS2h 51m
23. The Chemistry of Thioesters, Phophate Ester and Phosphate Anhydrides1h 10m
24. Enolate Chemistry: Reactions at the Alpha-Carbon1h 53m
25. Condensation Chemistry2h 9m
26. Amines1h 43m
27. Heterocycles2h 0m
28. Carbohydrates5h 53m
29. Amino Acids4h 20m
30. Peptides and Proteins2h 42m
31. Catalysis in Organic Reactions1h 30m
32. Lipids 2h 50m
33. The Organic Chemistry of Metabolic Pathways2h 52m
34. Nucleic Acids1h 32m
35. Transition Metals6h 14m
36. Synthetic Polymers1h 49m

15. Analytical Techniques:IR, NMR, Mass Spect

1H NMR:Spin-Splitting Complex Tree Diagrams

Organic Chemistry

15. Analytical Techniques:IR, NMR, Mass Spect

1H NMR:Spin-Splitting Complex Tree Diagrams

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7:53 minutes

Problem 68

Textbook Question

Draw a splitting diagram for the H_b proton if J_bc = 10 and J_ba = 5.

Verified step by step guidance

Step 1: Analyze the molecular structure provided in the image. The molecule contains a double bond with three protons labeled Ha, Hb, and Hc. Hb is the proton of interest, and it is coupled to both Ha and Hc.

Step 2: Understand the coupling constants provided. Jbc = 10 Hz represents the coupling between Hb and Hc, while Jba = 5 Hz represents the coupling between Hb and Ha. These values indicate the strength of the spin-spin interactions.

Step 3: Determine the splitting pattern for Hb. Since Hb is coupled to two different protons (Ha and Hc) with different coupling constants, the splitting will result in a doublet of doublets. The larger coupling constant (Jbc = 10 Hz) will cause the initial splitting into two peaks, and the smaller coupling constant (Jba = 5 Hz) will further split each of these peaks into two smaller peaks.

Step 4: Draw the splitting diagram. Start by representing Hb as a single peak. Split this peak into two peaks separated by 10 Hz due to the coupling with Hc. Then, split each of these peaks into two smaller peaks separated by 5 Hz due to the coupling with Ha.

Step 5: Label the diagram appropriately. Indicate the coupling constants (Jbc = 10 Hz and Jba = 5 Hz) on the diagram to show the source of each splitting. Ensure the relative intensities of the peaks are consistent with the expected splitting pattern (1:1:1:1 for a doublet of doublets).

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Key Concepts

Here are the essential concepts you must grasp in order to answer the question correctly.

Nuclear Magnetic Resonance (NMR) Spectroscopy

NMR spectroscopy is a powerful analytical technique used to determine the structure of organic compounds. It relies on the magnetic properties of certain nuclei, such as hydrogen, to provide information about the number of hydrogen atoms and their environment in a molecule. The splitting patterns observed in NMR spectra arise from the interactions between neighboring protons, which is crucial for interpreting the data.

Spin-Spin Coupling

Spin-spin coupling, or J-coupling, refers to the interaction between the magnetic spins of neighboring nuclei, which leads to the splitting of NMR signals. The coupling constants (J values) quantify the strength of these interactions, measured in Hertz (Hz). In the given question, Jbc = 10 Hz and Jba = 5 Hz indicate the coupling between protons Hb and Hc, and between Hb and H2a, respectively, which will influence the splitting pattern of the Hb proton.

Multiplicity of NMR Signals

The multiplicity of an NMR signal indicates the number of peaks observed for a particular proton signal, which is determined by the number of neighboring protons. This is described by the n+1 rule, where n is the number of neighboring protons. For the Hb proton, the multiplicity will depend on the coupling with protons Hc and H2a, leading to a specific splitting pattern that can be visualized in a splitting diagram.