Types of Reagent:
Electrophilic reagent: All electron deficient atom or group of atoms is known as Electrophilic agent, the electrophile attacks at the electron rich centre.
- all positively charged species are electrophile
- The compound in which the octet of central atom is not complete
- all the compound in which the central atom can expand its octet
- all polarizing functional group are electrophilic as well as nuelophile
Nucleophilic reagent: All electron rich compounds are nucleophile and attack at the electron deficient centre.
- all negatively charged species
H-, Cl-, NO2-, Br-, CH3- etc.
- The compound in which the central atom has lone pair of electron.
- all Organ metallic compounds are NucleophileR – Mgx, RLi, R2Cd
- The compound having π e- density
The power of nucleophile is known as nucleophilicity.
⇒The nucleophilicity of negative charge is greater than the nucleophilicity of lone pair
⇒If lone pair or negative charge is present on the different atom then less electronegativity, more will be the Nucleophilicity.
CH-3, NH-2, OH-2, F
Nucleophilicity : CH-3> NH-2> OH-2> F-
⇒NH3 < PH3 < AsH3 < SbH3 < BiH3 (Nucleophilicity)
⇒If negative charge or lone pair of electron is present on the same atom then the less stable negative charge will be the better nucleophile for example,
Activator & Deactivator:
The groups in benzene which show +M effect or +I effect Increases the electron density on benzene it means they activate the ring towards electrophile and known as activator.
The groups which shows +I (resultant) or +M effect then negative charge is developed at the Ortho & Para position this means electron density is minimum at the Ortho & Para positions and Electrophile will attack at the meta position the groups are known as meta director.
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