CARBENES & NITRENES

                                                  CARBENES

         

      Carbenes are highly reactive molecule containing a divalent carbon atom.      

      Neutral, divalent, highly reactive in nature.

       They are highly unstable that’s why highly reactive in nature.

        Simplest carbene is .

      General preparation :

     Carbenes are related to carbanions through  elimination reaction

      
                                              Di-halo carbene 

         Hybridization of the divalent carbon may be as well as .

             hybrid carbine is of 2 types

                sp-hybrid carbine is always triplet.

The decreasing order of stability of different types of singlet carbenes is as follows:

Carbenes can exist in singlet as well as in triplet  state but

                                                              exists only in single state.

    Important points Regarding carbene Reaction:

    Mainly give two types of reactions

Important points about Carbene:

        

       Unusual carbene containing species.

         

       It has a carbon with a lone pair and an empty orbital. The empty orbital makes the carbon very    reactive

         is the simplest carbene (methylene)

       Obtained by heating diazo methane

                                                          

                                                                   Nitrene

    As carbene is for carbon nitrene is for nitrogen. It is analogues of carbene.

          There is possibility of two spin states for a nitrene depending on whether the two non bonding            electrons have their spins paired or parallel

           They are highly reactive because they are highly unstable and always form as a reaction        intermediate.

 Nature:

         In general, nitrene obeys Hund’s rule and ground state triplet with two degenerated sp-orbitals containing a single electron each.