Synthesis, structure and anticancer activities of Cd(II), Cu(II) and Pd(II) complexes with 5,7‐dichloro‐8‐hydroxylquinoline‐2‐carboxaldehyde‐4‐chloro‐2‐aminothiophenol

Three new complexes of Cd(II), Cu(II) and Pd(II) with 5,7‐dichloro‐8‐hydroxyquinoline‐2‐carboxaldehyde‐4‐chloro‐2‐aminothiophenol (QNS), that are [Cd(QNS‐1H)Cl] (1), [Cu(QNS‐1H)2] (2) and [Pd(QNS‐1H)Cl] (3), were synthesized. Their structures were determined by ESI‐MS, EDX, IR and 1H NMR spectroscopies. The results showed that in (1) and (3) complexes the ratio of M(II):QNS ligand is 1:1, M(II) is bound to QNS through O, Nquinoline and Nbenzothiazole atoms. In complex (2), Cu(II) is bound to the QNS ligand in the 1:2 ratio through Oquinoline and Nquinoline atoms. The complexes were tested for cell in vitro cytotoxicity on human cancer cells. Complex (1) gives better antitumor activity than the remaining complexes on four cancer lines including KB, Hep‐G2, A549 and MCF‐7. The effect of complex (1) on KB and MCF‐7 is higher than cisplatin, a cancer treatment drug, with IC50 values of 15.01 and 17.94 μM, respectively.