Tautomeric Schiff bases: Iono-, solvato-, thermo- and photochromism

The review article summarizes the recent data about novel tautomeric iono-, solvato-, thermo- and photochromic Schiff bases. This contribution focuses on the factors determining tautomeric equilibrium and on the investigations into the proton transfer mechanisms.

► Schiff bases can exist in enolimine and ketoenamine forms.
► The type of the dominant tautomer depends on the structure, solvent and temperature.
► The structure of the photoform of salicylideneanilines is the E-NH form.