CHEM 2021 Chapter Notes - Chapter 17: Electrophilic Aromatic Substitution, Sigma Bond, Nitro Compound
Document Summary
Chapter 17: electrophilic aromatic substitution, sigma complex: the resonance-stabilized carbocation formed when benzene"s pi electrons attack a strong electrophile. Iodination: needs an oxidizing agent, like nitric acid, to produce iodide cation: nitration: Nitro group is strongly deactivating based on its resonance forms. Inductive effect: alkyl groups are activating substituents and ortho/para directors. It is called the inductive effect because alkyl groups can donate electron density to the ring through the sigma bond, making them more active. If the substituent on the ring is e- donating: ortho/para positions are activated. If the substituent is e- withdrawing: ortho/para positions are deactivated. Most e- withdrawing groups are deactivators and meta directors. Inductive effect: halogens are deactivators because they are electronegative and can withdraw e- density from the ring along the sigma bond. Resonance effect: the lone pairs on the halogen can be used to stabilize the sigma complex by resonance.
