Electrophilic Aromatic Substitution: NO2 & NO Groups

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Discussion Overview

The discussion revolves around the behavior of nitro (-NO2) and nitroso (-NO) groups in electrophilic aromatic substitution reactions, specifically their directing effects and deactivation properties. Participants explore the electronic structures and resonance forms associated with these groups, as well as the implications for substitution patterns on aromatic rings.

Discussion Character

  • Technical explanation
  • Conceptual clarification
  • Debate/contested

Main Points Raised

  • One participant asserts that the NO2 group directs meta substitution with deactivation, while the nitroso group directs ortho-para substitution with deactivation.
  • Another participant questions the clarity of the original question and requests more specific details about the difficulties faced by the poster.
  • A participant points out that the nitroso group is correctly represented as -ONO and encourages the original poster to clarify their confusion.
  • One reply suggests writing out resonance structures for the aryl cation to understand the directing effects of the nitroso group, indicating uncertainty about its ortho-para directing behavior.
  • A participant mentions that halides like bromine also direct ortho/para while deactivating the ring, suggesting that different effects need to be considered to justify these observations.

Areas of Agreement / Disagreement

Participants express differing views on the directing effects of the nitroso group, with some uncertainty about its behavior. There is no consensus on the original poster's question or the implications of the nitroso group's effects.

Contextual Notes

Some participants note the need for clarification on the definitions and representations of the nitroso group, as well as the resonance structures involved in the reactions. There is also mention of potential confusion regarding the deactivation and directing effects of different substituents.

Who May Find This Useful

This discussion may be useful for students or individuals studying organic chemistry, particularly those interested in electrophilic aromatic substitution and the effects of substituents on aromatic compounds.

ddrplayboy
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The NO2 group directs meta with-deactivation in electrophilic aromatic substitution. The nitroso group - NO directs ortho-para with - deactivation. Write out the electroinc structures of - NO2 and -NO and explain the differences in behavior. Show all pertinent resonance forms for the addition of bromonium ino to form p-bromonitrosobenzene.
thanks for looking
 
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What is your question? We can't just answer your textbook question. What are you having trouble with in the problem?
 
First off, nitroso is written as -ONO. Please show where you are stuck; if you don't understand anything, be sure to post your question after you have studied to understand our responses.
 
Start by writing out the resonance structures for the aryl cation, "move the electrons around" as you have learned before, or should have. You should be able to notice why the nitroso group is supposed to direct ortho para ("supposed" since I haven't looked into this before). Ortho para with deactivation? doesn't ring a bell to me.
 
Last edited:
Halides like bromine on the aromatic ring will direct ortho/para while deactivating the ring as well. To justify this observation you will need to consider two different effects.
 
chem_tr said:
First off, nitroso is written as -ONO. Please show where you are stuck; if you don't understand anything, be sure to post your question after you have studied to understand our responses.

Edit: Nitroso may also be in the form of N=O, as we are dealing with organic substances; inorganic nitroso compounds are written as -ONO.
 

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