Multiple studies on salicylaldehyde derivatives, Schiff bases, and related compounds demonstrate the presence of strong intramolecular hydrogen bonding, which dictates their photophysical properties and proton transfer behavior.
The retrieved literature consistently supports the chemical fact that salicylaldehyde derivatives exhibit intramolecular hydrogen bonding (often forming O-H...N interactions that facilitate excited-state intramolecular proton transfer, or ESIPT). Papers 3, 6, 8, and 10 explicitly discuss these intramolecular hydrogen bonds in salicylaldehyde-based structures.