Structural effects of potentially hexadentate Schiff base ligands involving pyrrolic, etheric or thioetheric donors towards zinc(II) cation: Synthesis, characterization and crystal structures

The three new zinc (II) complexes (ZnL^m, m = 1-3) of potentially hexadentate Schiff base ligands containing N₄O₂ and N₄S₂ donors with pyrrole terminal binding groups H ₂L¹:[(1Z)-1H-pyrrole-2-ylmethylene]{2-[2-(2-{[(1Z)-1H- pyrrole-2-ylmethylene]amino}phenoxy)ethoxy]phenyl}amine, H₂L ²:[(1Z)-1H-pyrrole-2-ylmethylene]{2-[4-(2-{[(1Z)-1H-pyrrole-2- ylmethylene]amino}phenoxy)butoxy]phenyl}amine and H₂L ³:[1H-pyrrole-2-ylmethylene][2-({2-[(2-{[1H-pyrrole-2-ylmethylene] amino}phenyl)thio]ethyl}thio)phenyl]amine, were synthesized and physicochemically characterized. Cyclic voltammetry data indicate that the complexes are electrochemically inactive. The molecular structures of the complexes were determined by single crystal X-ray diffraction. The Zn(II) is five coordinated by N₄O donor set of the ligands in the ZnL ¹ and ZnL² and six coordinated by N₄S ₂ donor set in the ZnL³.