Complexes of platinum and palladium with β-diketones and DMSO: Synthesis, characterization, molecular modeling, and biological studies

• Four new complexes with mixed ligands were synthesized and characterized.
• Theoretical data show good agreement with the experimental results.
• The platinum complexes are more cytotoxic than the free ligands and carboplatin.
• Microbiological assays against Mycobacterium tuberculosis were performed.

This work reports on the synthesis and characterization of new complexes of the type [MCl(L)DMSO], where L = 4,4,4-trifluoro-1-phenyl-1,3-butanedione (HTPB) or 4,4,4-trifluoro-1-(2-thienyl)-1,3-butanedione (HTTA) and M = Pt2+ or Pd2+. These complexes were characterized by elemental analyses, conductivity measurements, FT-IR, UV–Vis, high-resolution mass spectra (HRESIMS) and TG/DTA. In the complexes, the metallic ions bind to β-diketone via the oxygen atoms and to DMSO molecule via sulfur atom. The structures of complexes were optimized and theoretical data showed good agreement with the experimental results. The cytotoxic activity of the compounds was evaluated in a chronic myelogenous leukemia cell line. The platinum complexes were more cytotoxic than the free ligands and carboplatin and are promising candidates for further investigations. As example, the compound [PtCl(TPB)(DMSO)] inhibits the growth of K562 cells with an IC50 value equal to 2.5 μM. Furthermore, microbiological assays against Mycobacterium tuberculosis showed that all complexes exhibit low cytotoxicity against this bacterial strain while the free ligands exhibited MIC values of approximately 10 μg mL−1.

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