Synthesis, crystal structure and anticancer activity of 4‑chloro-2-methoxybenzoic acid transition metal complexes

Abstract

Seven novel transition metal complexes were synthesized from a starting material of 4‑chloro-2-methoxybenzoic acid, I: [Cu(4-Cl-2-MOBA)2(Py)2(H2O)2]; II: [Cu(4-Cl-2-MOBA)2(Imz)2]; III: [Co(4-Cl-2-MOBA)2(H2O)3.5]; IV: [Ni(4-Cl-2-MOBA)2(H2O)6]; V: [Ni(4-Cl-2-MOBA)2(DMF)]; VI: [Ni(4-Cl-2-MOBA)2(3-NH2–5-hypy)2(H2O)2O3.67] and VII: [Zn2(4-Cl-2-MOBA)3(4,4′-bipy)(Py)(HAc)]n by a one-pot, solvothermal method. All complexes were characterized by elemental analysis (EA), Fourier transform infrared spectroscopy (FTIR), ultraviolet-visible spectroscopy (UV–Vis), electrospray ionization mass spectrometry (ESI-MS) and single-crystal X-ray diffraction analysis (XRD). Single crystal XRD analyses showed that central metal ion type, auxiliary ligands and solvents acted synergistically to determine structural diversity. Complexes I-VII had cytotoxic activity towards the human tumor cell lines, A549 and SMMC-7721. Complex I showed the most potent cytotoxicity with an IC50 value of 8.976 μM for lung cancer cells and 13.94 μM for liver cancer cells.