The textbook answer to this is that the triple bond consists of two orthogonal π systems whose interaction with each other is symmetry-forbidden. So as the attached figure shows, the two p-orbitals marked in red cannot participate in the aromatic system if the molecule’s structure is as drawn; th...
user228700
user228700
user228700
user228700
user228700
user228700
user228700
user228700
user228700
user228700
user228700
user228700
user228700
user228700
user228700
user228700
user228700
user228700
user228700
user228700
user228700
user228700
user228700
user228700
user228700
user228700
user228700