Zn (II), Cu (II), Co (II), and Ni (II) complexes bearing aza-heterocyclic ligands: synthesis, characterization, and anticancer activities

Due to their structural arrangements, coordination complexes have shown potential to combat various human diseases. Nitrogen heteroatoms are a fascinating class of coordination compounds with many applications in synthesis and medicine. Herein, four Co(II), Zn(II), Cu(II), and Ni(II) complexes (I–IV) such as [CoC₁₀H₁₄Cl₂N₆O₂] (I), [ZnC₆H₁₀Cl₂N₆O₂] (II), [Cu₂C₁₆H₃₄N₂O₁₂] (III), and [Ni₄C₈₀H₁₀₀N₁₆O₂₂] (IV) bearing aza-heterocyclic ligands have been synthesized under one-pot self-assembly conditions. The reaction of 2-amino-4-hydroxy-6-methylpyrimidine and 3-amino-5-hydroxypyrazole with CoCl₂·6H₂O and ZnCl₂, respectively, produced two mononuclear complexes (I)–(II) while two binuclear complexes (III)–(IV) (complex IV are in two halves) were synthesized using Cu (OAC)2·H₂O and NiCl₂·6H₂O, respectively, with salicylidene salicylhydrazide. Then, the complexes were characterized using NMR, FTIR UV–Vis, X-ray diffraction, TGA, and elemental analysis techniques to confirm their structures. The synthesis complexes were employed against different human tumour cell lines (SMMC-7721, A549, MDA-MB-231, and SW480). The best activity was demonstrated by complex (II) against human tumour cell lines SMMC-7721 (liver cancer cell) with an IC50 value of (6.356 µM).