A heterobinuclear complex [CoNa(C₁₅H₁₀NO₄F)₂(CH₃OH)]₂ with Schiff base (C₁₅H₁₀NO₄F: 2-amino-4-fluorobenzoic acid—3-methoxysalicylaldehyde) was synthesized and characterized by IR spectroscopy, elemental analysis and single crystal X-ray diffraction. X-ray crystallography shows that the cobalt atom is six-coordinated by two nitrogen atoms from -C=N-, two carboxylate oxygen atoms and two hydroxyl oxygen atoms in different ligands, while the sodium atom is seven-coordinated by two methoxy oxygen atoms, two hydroxyl oxygen atoms in different ligands, two oxygen atoms in the same carboxylate and one oxygen atom of solvent methanol. The anticancer activity of the complex on human breast cancer MDA-MB-231 cells was investigated. The studies indicate that the complex can inhibit the cellular proliferation. In addition, it has proteasome-inhibitory activity in human breast cancer MDA-MB-231 cells. The inhibition of the tumor proteasomal activity results in the accumulation of ubiquitinated proteins and ubiquitinated form of IκB-α, a natural proteasome substrate, followed by induction of apoptosis. The results suggest that the Schiff base metal complex, as a potent proteasome inhibitor, has potential to be developed into a novel anticancer drug.

Keywords: Schiff base; Metal Complex; Crystal Structure; Anticancer; Proteasome;