Spectral and thermal studies of Mn(II), Co(II), Ni(II), Cu(II), Zn(II) and Cd(II) complexes with 3-methylglutaric acid

Mn(II), Co(II), Ni(II), Cu(II), Zn(II) and Cd(II) 3-methylglutarates were prepared as solids with general formula MC6H8O4. nH(2)O, where n=0-8. Their solubilities in water at 293 K were determined (7.0 . 10(-2)-4.2 . 10(-3) mol dm(-3)). The IR spectra were recorded and thermal decomposition in air was investigated. The IR spectra suggest that the carboxylate groups are mono- or bidentate. During heating the hydrated complexes lose some water molecules in one (Mn, Co, Ni, Cu) or two steps (Cd) and then mono- (Cu) or dihydrates (Mn, Co, Ni) decompose to oxides directly (Mn, Cu, Co) or with intermediate formation of free metals (Co, Ni). Anhydrous Zn(II) complex decomposes directly to the oxide ZnO.