Synthesis and Structure of Copper(II) Complexes with N-[(E)-[2-(p-Tolylsulfonylamino)Phenyl]Methyleneamino]Pyridine-4-Carboxamide

Three new Cu(II) complexes based on N-[(E)-[2-(p-tolylsulfonylamino)phenyl]methyleneamino]pyridine-4-carboxamide (H₂L) are prepared. The Cu(II) complexes are characterized by elemental analysis and IR spectroscopy. It was established that the synthesis in a DMF:methanol (1:1) solution using Cu(CH₃ COO)₂·H₂O yields a complex polymer whose structure was determined by single-crystal XRD. The HL ligand is coordinated in a tridentate manner to the Cu(II) ion in the complex polymer via the deprotonated nitrogen atom of the tosylamino group, the azomethine nitrogen atom, and the hydrazone oxygen. The fourth bond is due to the coordination of the pyridine nitrogen of the neighbouring molecule and leads to the formation of zigzag polymer chains. Also, one DMF molecule is axially coordinated to the Cu(II) ion, and another one is located inside the unit cell as a solvate. The synthesis in the same solution using CuCl₂ or Cu(ClO₄)₂·6H₂O yields mononuclear CuLX complexes (X = Cl, ClO₄).