Synthesis, structural elucidation, microbial, antioxidant and nuclease activities of some novel divalent M(II) complexes derived from 5-fluorouracil and l-tyrosine

Novel N2O2 sequence of mononuclear amino acid metal(II) complexes (1a-1e) was synthesized from 5-fluorouracil (5-FU: A) and l-tyrosine (tyr: B) with Mn(II), Co(II), Ni(II), Cu(II) and Zn(II) ions. The synthesized complexes were structurally characterized by analytical, spectral (FT-IR, UV-vis, 1H NMR, FAB-Mass, TGA/DTA and EPR) as well as molar conductance and magnetic studies. From spectral studies, both the ligands act as bidentate and they bind metal(II) ions through deprotonated-N3 and C4O atoms and amino-N and deprotonated carboxylato-O atoms, respectively, to form a stable metal chelate. The observed low molar conductance values suggest a non-electrolytic nature. Calculated g tensor values of Cu(II) complex (1d) at 77 and 300 K confirm their geometry. Thermal behavior of metal(II) complexes (1a-1c) shows loss of coordinated water molecules in the first step followed by decomposition of ligand moieties in a respective manner and leads to form air stable metal oxide as final residues. Powder X-ray diffraction and SEM studies illustrate that all the complexes have uniform microcrystalline with homogenous morphology. Mn(II), Ni(II) and Cu(II) complexes show significant in vitro antimicrobial and antioxidant activities than 5-fluorouracil(A). Moreover, the nuclease studies of Ni(II) and Cu(II) complexes (1c and 1d) show considerable DNA binding and oxidative DNA cleavage activities than other complexes.