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

16. Conjugated Systems

Stability of Conjugated Intermediates

Organic Chemistry

16. Conjugated Systems

Stability of Conjugated Intermediates

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3:42 minutes

Problem 27a

Textbook Question

Draw the important resonance contributors for the following cations, anions, and radicals.
(a)

Verified step by step guidance

Step 1: Identify the structure provided in the image. The molecule contains a carbocation (CH2+) attached to a conjugated system of double bonds. This indicates that resonance contributors can be drawn by delocalizing the positive charge across the π-system.

Step 2: Begin by moving the π-electrons from the double bond adjacent to the carbocation towards the carbocation. This creates a new resonance structure where the positive charge is shifted to the carbon atom that was part of the double bond.

Step 3: Continue the resonance process by moving the π-electrons from the next double bond in the conjugated system towards the newly formed carbocation. This results in another resonance structure where the positive charge is further delocalized.

Step 4: Repeat the process for the remaining double bond in the conjugated system, ensuring that the positive charge is distributed across the entire π-system. Each resonance structure should maintain the overall charge and connectivity of the molecule.

Step 5: Verify that all resonance contributors are valid by checking that each structure adheres to the rules of resonance (e.g., no violation of the octet rule, proper placement of charges). Highlight the delocalization of the positive charge as the key stabilizing feature of the molecule.

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Key Concepts

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

Resonance Structures

Resonance structures are different ways of drawing the same molecule that illustrate the delocalization of electrons. They help in understanding the stability and reactivity of a compound. In resonance, the actual structure is a hybrid of these contributors, which can affect properties like acidity, basicity, and reactivity.

Cation Stability

Cation stability refers to the relative stability of positively charged species. Factors influencing cation stability include the degree of alkyl substitution, resonance stabilization, and the electronegativity of adjacent atoms. More stable cations are generally formed from structures that allow for greater electron delocalization.

Electron Delocalization

Electron delocalization occurs when electrons are spread over multiple atoms rather than localized between two. This phenomenon is crucial in resonance structures, as it allows for the stabilization of charged species like cations and anions. Delocalization can lower the energy of a molecule, making it more stable and less reactive.

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