Reaction intermediates in organic chemistry

Reaction intermediates in organic chemistry 

     
        A reaction intermediate is a  short lived high energy, highly reactive cannot be isolated, which is format in between reactant  and product.
        Example : Carbocation,  carboanion,  freeradical, carbene, benzyne and nitrenes.

Carbocation :- 

Species   having a is positively charged carbon atom and six valency cell electron is called Carbo cation.

          the carbon cations by heterolytic cleavage of a covalent bond.

Example :

Shape of carbocation :- 

 The carbocation atom of carboncation is Sp2 hybridized.
Therefore the shape of carboncation is planar triangle having bond angle 120 degree.
            The perpendicular P-orbital is lying vacant.

     

                   

 There are two types of carboncation :-
​

1. Carbonium ion /Classical carbocation :-

                       Example :

​2. Non-classical carbonium ion :-

                       Example :

           In non classical carbocation the co-ordination number of positively charged is 4-5.

Stability of carbocation :-

 Tropylium > Tributyl methyl > Benzyl carbocation >Allyl carbocation > 3 degree butyl carbocation > Isoproyl carbocation > CH3CH2+ > CH3+


The stability of carbocation is explained on the besis of -

        1. ​Inductive effect.
        ​2. Steric effect.
        3. ​Resonance effect .
        ​4. Solvation effect .
        5. ​Hyper conjugation .