COPPER AND SILVER COMPLEXES SUPPORTED BY STERICALLY HINDERED β-DIKETONATES DIFFERING IN THE PRESENCE OF FLUORINATED MOIETIES

Although β-diketones represent one of the oldest classes of chelating ligands, their coordination chemistry continues to attract much interest, due to the ability of related metal complexes to support several unique and important catalytic reactions and for their applications as biochemically active agents. It is often noted that even modestly sterically hindered β-diketones offer improvements over the parent acetylacetone. β-diketones are known to form complexes with almost every metal, and they have been used as supporting ligands for metal-based anticancer agents [1]. In particular, the phenyl ring substituents increase the lipophilicity and improve cellular uptake, whereas the electron-withdrawing CF3 groups can modulate the pharmacokinetic and physicochemical properties and the chemical reactivity of the resulting metal complexes. Therefore, as part of our continuous investigation on the chemical and biological properties of metal-based coordination compounds, we report here a study on the syntheses, characterization, and biological evaluation of new homoleptic ([ML2]; M = Mn(II), Fe(II), Co(II), Ni(II), Cu(II) and Zn(II)) and heteroleptic ([ML(PR3)n]; M = Cu(I) or Ag(I); PR3 = PR3 or PTA) metal-complexes supported by the anion of sterically hindered β-diketonate ligands, 1,3-dimesitylpropane-1,3-dione (HLMes) and 1,3-bis(3,5-bis(trifluoromethyl)phenyl)-3-hydroxyprop-2-en-1-one (HLCF3). A particular attention was devoted to the synthesis of Cu(II) and Cu(I) species, also in view of their biological activity as potential antiviral and anticancer agents.