ABSTRACT
A series of new Zn(II) complexes with flufenamic acid (flu) has been synthesized, namely [Zn3(dmso)2(flu)6] (1), [Zn3(flu)6(py)2] (2), [Zn(flu)2(tmen)] (3), [ZnCl(flu)(neo)] (4), and [Zn(cyclam)(flu)2] (5), where py=pyridine, tmen=N,N,N',N'-Tetramethylethylene diamine, neo=2,9-Dimethyl-1,10-phenanthroline and cyclam=1,4,8,11-Tetraazacyclotetradecane. These complexes have been characterized by infrared spectroscopy, single-crystal X-ray structure analysis, elemental and thermal analysis. All complexes contain deprotonated flufenamic acid coordinated via carboxylato group to zinc atoms, but their structures differ in the carboxylato binding mode, the coordination number of the central atom, the shape of the coordination polyhedra and the resultant supramolecular structures. Furthermore, an interaction of complexes with calf-thymus DNA (CT DNA) and human serum albumin (HSA) has been investigated by spectroscopic techniques. Moreover, the complexes 1 and 2 inhibit the catalytic activity of topoisomerase I at 60µM.
Subject(s)
Coordination Complexes/pharmacology , DNA/chemistry , Serum Albumin, Human/chemistry , Topoisomerase I Inhibitors/pharmacology , Zinc/chemistry , Animals , Anti-Inflammatory Agents, Non-Steroidal/chemical synthesis , Anti-Inflammatory Agents, Non-Steroidal/chemistry , Cattle , Coordination Complexes/chemical synthesis , Coordination Complexes/chemistry , DNA Topoisomerases, Type I/metabolism , Flufenamic Acid/chemical synthesis , Flufenamic Acid/chemistry , Humans , Ligands , Molecular Structure , Topoisomerase I Inhibitors/chemical synthesis , Topoisomerase I Inhibitors/chemistryABSTRACT
Three mononuclear complexes [Co(biq)X2] (biq = 2,2'-biquinoline; X = Cl, Br, I) were prepared by a solvothermal method and characterized by single-crystal X-ray diffraction. In all three complexes the Co(ii) atom is tetrahedrally coordinated by one biq ligand bonded in a chelate manner and two halogenido ligands. Hydrogen bonding interactions (C-HX) along with the π-π interactions contribute to the stability of the formed packing. Magnetic measurements as well as ab initio calculations revealed that the complexes possess a sizable easy-plane magnetic anisotropy (D > 0). They display a superparamagnetic behaviour in an applied external field that culminates between BDC = 0.2-0.3 T. Two relaxation processes are observed; the faster can be analysed in terms of the direct and Orbach processes yielding U/kB = 42.6 K and τ0 = 1.9 × 10(-10) s for X = Cl, U/kB = 39.6 K and τ0 = 1.2 × 10(-10) s for X = Br and U/kB = 57.0 K and τ0 = 3.2 × 10(-13) s for X = I at BDC = 0.2 T.
