The n which does not contribute to the basicity for the compound is
Answers
Basicity defines the stability of lone pairs of atoms. It does not depend on the number of lone pairs. If the lone pair is stable, it does not get involved in coordination formation as the atom has potential to keep the other pair in its vicinity without sharing with Lewis acid. Besides, basicity also depends on resonance, electronegativity, atomic radius, inductive effect, formal charges.
When we consider those having basicity of 1,3, 7, there are lone pairs involved in pi system of aromatic bonds. The other pair of electrons which are not involved in pi aromatic bonds are directed away from the rings and hence acts as Lewis base.
When considering those having basicity of 9, the electrons are sp2 hybridized in which the lone pair is involved in aromatic pi system. But like those of basicity of 1,3,7, these don’t have any lone pairs of electrons that points away from the rings. Instead there is a sigma bond.
So when comparing those compounds having 4,5,7,8,9 , it found that those having 4,5,7,8 have lone pair of electrons but those having 9 donates its lone pair to the ring. In all other nitrogen atoms, the lone pairs of electrons participate in resonance. But also it is noted that the lone pairs of electrons in N-9 take part in resonance making it unavailable by donation which makes it non basic.
Hence, the n which does not contribute to basicity of the compound is N-9
Hello...
Your answer is N9
Those having basicity of Nine, the Electrons are sp2 hybridized where the lone combine within the aromatic pi system. However like those of Basicity of 1,3,7,8. They don’t have any lone pairs of Electrons that time removed from the rings. So once examine of those Compounds having 4,5,7,8,9 it found that those having 4,5,7,8 have alone combine of electrons however those having 9 donates its lone combine to the ring. Altogether different Nitrogen atoms, the lone pairs of electrons participate in resonance. It is possible that the lone pairs of electrons in N9 participate in Resonance by creating it unavailable by donation which makes it nonbasic.
Hope it helped.