Reversible and irreversible thermochromism of some Schiff base metal complexes

Summary Nickel(II) and copper(II) complexes of Schiff bases derived from salicylaldehyde, 2-hydroxy-1-naphthaldehyde, 2,4-dihydroxybenzaldehyde, 2,3-dihydroxybenzaldehyde or 5-chlorosalicylaldehyde and 8-aminoquinoline have been prepared and characterized. Several of the complexes are thermochromic in the solid state. The origin of the thermochrornism is discussed in terms of changes in ligand field strength and coordination geometry. These changes were studied by means of thermal and spectral methods.