1 / 10

Sigma Complex

Sigma Complex. Intermediate is more stable if nitration occurs at the ortho or para position. =>. Energy Diagram. =>. =>. Activating, O -, P - Directing Substituents. Alkyl groups stabilize the sigma complex by induction , donating electron density through the sigma bond.

palti
Download Presentation

Sigma Complex

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript


  1. Sigma Complex Intermediate is more stable if nitration occurs at the orthoor para position. =>

  2. Energy Diagram =>

  3. => Activating, O-, P-Directing Substituents Alkyl groups stabilize the sigma complex by induction, donating electron density through the sigma bond. Substituents with a lone pair of electrons stabilize the sigma complex by resonance.

  4. Nitration of Anisole Ortho attack Meta attack Para attack =>

  5. => The Amino Group Aniline reacts with bromine water (without a catalyst) to yield the tribromide. Sodium bicarbonate is added to neutralize the HBr that’s also formed.

  6. Summary ofActivators =>

  7. Deactivating Meta-Directing Substituents Electrophilic substitution reactions for nitrobenzene are 100,000 times slower than for benzene. The product mix contains mostly the meta isomer, only small amounts of the orthoand para isomers. Meta-directors deactivate all positions on the ring, but the meta position is less deactivated. =>

  8. Ortho Substitutionon Nitrobenzene =>

  9. Para Substitution on Nitrobenzene =>

  10. Meta Substitutionon Nitrobenzene =>

More Related