Sodium, Potassium, and Lithium Complexes of Phenanthroline and Diclofenac: First Report on Anticancer Studies

Diclofenac or 2-[(2',6'-dichlorophenyl)amino]phenyl}acetic acid (dcf) is a nonsteroidal anti-inflammatory drug, and 1,10-phenanthroline (phen) is a well-known enzyme inhibitor. In this study, three new alkali metal complexes (1-3) containing both phen and dcf were prepared, and their structures were characterized by a variety of analytical techniques including infrared and UV-vis spectroscopy, ¹H NMR and ¹³C NMR elemental analysis, mass spectrometry, and single-crystal X-ray diffraction analysis. In these complexes, phen binds via a N,N'-chelate pocket, while the monoanionic dcf-ligand remains either uncoordinated (in the case of 1 and 3) or coordinated in a bidentate fashion (in the case of 2). All three complexes crystallize in the triclinic space group P-1. [Na₂(phen)₂ (H₂O)₄][dcf]₂ (1) is a dinuclear sodium complex, where two crystallographically identical Na⁺ cations adopt a distorted five-coordinate spherical square-pyramidal geometry, with a [N₂O₃] donor set. [K₂(phen)₂(dcf)₂(H₂O)₄] (2) is also a dinuclear complex where the crystallographically unique K⁺ cation adopts a distorted seven-coordinate geometry comprising a [N₂O₅] donor set. [Li(phen)(H₂O)₂][dcf] (3) is a mononuclear lithium complex where the Li⁺ cation adopts a four-coordinate distorted tetrahedral geometry comprising a [N₂O₂] donor set. The complexes were evaluated for their anticancer activity against lung and oral cancer cell lines as well as for their antibacterial potential. The prepared complexes displayed very good antibacterial and anticancer activities with an excellent bioavailability.