A series of halogen substituted 5-X-N-(8-quinolyl)salicylaldimines (HqsalX, X = F 1, Cl 2, Br 3 and I 4) have
been prepared, characterized and the crystal structures of all four are reported. The compounds form
stacks, in most cases held together either by p–p or lone pair(N)–p interactions. All compounds exhibit
an intramolecular OAH N hydrogen bond with 2 also displaying an intermolecular OAH O hydrogen
bonding square. Additional CAH N/O and CAH p interactions serve to link neighbouring HqsalX molecules
with 3 and 4 forming narcissistic dimers. While the halogen has a profound effect on the structure
it is not involved in either hydrogen or halogen bonding in any of the structures. DFT calculations suggest
that the conformational preference is dependent on the halogen.