Mn(II), Co(III), Ni(II), Cd(II) and Cu(II) Complexes of 2-Thenoyltrifluoroacetone: Syntheses, Structures, Photoluminescence, Thermal, Electrochemical and Antitumor Studies on Dalton's Lymphoma Cells

Five complexes [Mn(ttfa)(2)(py)(2)] (1), [Co(ttfa)(3)] (2), [Ni(ttfa)(2)(en)] (3), [Cd(ttfa)(2)(bpy)] (4), and [Cu(ttfa)(2)(py)] (5) {where Httfa=2-thenoyltrifluoroacetone} have been synthesized and characterized by elemental analyses, IR, UV-Vis and single crystal X-ray diffraction data. Both oxygen atoms of ttfa chelate with the metal ions forming six-membered C3O2M chelate rings in the complexes. In complexes 1-4 the metal ion adopts a distorted octahedral geometry while the complex 5 is distorted square pyramidal. In the solid state, complexes are stabilized by various types of inter-intramolecular interactions. Upon excitation at about 29500 cm(-1), complexes 1, 2, 3 and 5 exhibit blue emissions while the complex 4 emits violet colour. Electrochemical studies of Httfa and complexes show irreversible redox behavior. Thermal degradation of the complexes as analyzed by TG-DTA suggests the formation of their respective metal oxides as final thermally stable chemical entities. Httfa, complex 1 and 5 are studied for cytotoxicity on Dalton's lymphoma cells using MTT assay, apoptotic analysis and DNA fragmentation assay which reveals their order of activity as complex 5 > complex 1 > Httfa.