A new cobalt(II) 4-hydroxobenzoate, [Co2(C7H5O3)2(NO3)2(H2O)4]2H2O was synthesized as binuclear complex and characterized by elemental analyses (CHN), spectroscopic (infrared, electronic, x-ray powder diffraction, scanning electron microscopy SEM,) studies, magnetic susceptibility measurements and thermal analysis. This complex is a new type of 4-hydroxybenzoate bridged metal complex in which the carboxylate ligand is p-hydroxobenzoic acid. Bridging co-ordination modes for the carboxylates were indicated by the presence of (νasym–νsym) vibrations in the infrared spectra nearly the same as observed for ionic compounds. The magnetic moment value of cobalt(II) 4–hydroxybenzoate determined in at 300 K is 4.45 BM which refer to octahedral geometry. Thermo gravimetric analysis (TGA) of the hydrated water molecules shows that the first degradation step is associated with the release of water molecules followed by the decomposition of the 4-hydroxobenzoate, nitrato and coordinated water molecules. According to Horowitz-Metzger (HM) and Coats-Redfern methods, the kinetic parameters for the non-isothermal degradation of this complex were calculated using thermogravimetric data.
Key words: 4-Hydroxobenzoic acid; Cobalt(II) ions; X-ray powder diffraction; Spectroscopic data; Thermal analysis; Nanocomposites; Biological evaluation;
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