Synthesis and characterization of novel Cd(II), Zn(II) and Ni(II) complexes with 2-quinolinecarboxaldehyde selenosemicarbazone. Crystal structure of bis(2-quinolinecarboxaldehyde selenosemicarbazonato)nickel(II)

New complexes of Cd(II), Zn(II) and Ni(II) with 2-quinolinecarboxaldehyde selenosemicarbazone (Hqasesc) were synthesized and structurally characterized. The structure of the ligand, Cd(II) and Zn(II) complexes was determined by NMR and IR spectroscopy, elemental microanalysis and molar conductivity measurements. Both complexes occur in solution in two forms, the major tetrahedral and minor octahedral. In the major Cd(II) complex one qasesc− ligand is coordinated as a tridentate, the fourth coordination site being occupied by acetate, while in the major Zn(II) complex two qasesc− ligands are coordinated as bidentates. In both minor complexes two qasesc− ligands are coordinated as tridentates forming the octahedral geometry around the central metal ion. The only paramagnetic complex in the series is Ni(II) complex for which X-ray structure analysis was performed. The complex has the angularly distorted octahedral geometry with two qasesc− ligands coordinated as tridentates, in a similar way as in the minor complexes of Cd(II) and Zn(II).

A ligand 2-quinolinecarboxaldehyde selenosemicarbazone (Hqasesc) was synthesized and coordinated with Zn(II), Cd(II) and Ni(II). Single crystal X-ray analysis shows that the Ni(II) coordinates two deprotonated qasesc− ligands giving the octahedral bischelate complex. NMR study showed a difference in structures of Cd(II) and Zn(II) complexes in solid state and in solution. Preliminary results of cytotoxic activity determination showed that the complexes are more active than the ligand.Figure optionsDownload as PowerPoint slide