Mixed-ligand ternary complexes of potentially pentadentate but functionally tridentate Schiff base chelates

► A new potentially pentadentate N3S2 Schiff base ligand has been structurally characterized. ► It reacts with nickel(II) salts giving cationic mixed-ligand ternary complexes containing three ligands viz. the Schiff base as an NNN tridentate chelating agent, a bidentate NS ligand and an anion in the coordination sphere. ► The reaction of the Schiff base with copper(II) ion leads to its complete hydrolysis with the concomitant formation of copper(II) complexes of the parent amine from which the Schiff base was synthesized.