Synthesis of a sulfonamide-Schiff base ligand and its Cu(II), Fe(III) and Co(III) complexes

An unsymmetric ligand bearing a salicylimine side and a 2-nitrobenzenesufonamide side has been synthesized in two simple steps. Complexations with Cu(II), Fe(III) and Co(II) – which oxidizes to Co(III) once complexed – indicate that the ligand can be either bidentate or tridentate depending on the geometric preferences of the metal ion and whether the sulfonamide is deprotonated. The obtained crystal structures are also stabilized via hydrogen bonds and π–π stacking interactions.