Question
Which of the following is an aromatic species ?
A.
B.
C.
D.
Answer :
Solution :
An aromatic compound have cyclic clouds of delocalised $$\left( {4n + 2} \right)\pi $$ electrons above and below the plane of the molecule. Among the given three compounds, only compound (C) satisfies these conditions.
Carbon bearing $$ - N{O_2}$$ ( or $$ - C{H_3}$$ ) group is $$s{p^3}$$ hybridised and does not have a $$p$$ orbital with the result delocalisation of $$\pi $$ electrons over the complete ring is interrupted.
$$4\pi $$ electrons and 2 non-bonding electrons ( present in $$p$$ orbital of $$N$$ ) form a cyclic cloud of $$6\pi $$ electrons
An aromatic compound have cyclic clouds of delocalised $$\left( {4n + 2} \right)\pi $$ electrons above and below the plane of the molecule. Among the given three compounds, only compound (C) satisfies these conditions.
Carbon bearing $$ - N{O_2}$$ ( or $$ - C{H_3}$$ ) group is $$s{p^3}$$ hybridised and does not have a $$p$$ orbital with the result delocalisation of $$\pi $$ electrons over the complete ring is interrupted.
$$4\pi $$ electrons and 2 non-bonding electrons ( present in $$p$$ orbital of $$N$$ ) form a cyclic cloud of $$6\pi $$ electrons