Complexes of 3,4-dimethoxybenzoic acid anion with Cu(II), Co(II), La(III), and Nd(III)

Abstract

Physico-chemical properties of 3,4-dimethoxybenzoates of Co(II), Cu(II), La(III) and Nd(III)were studied. The complexes were obtained as hydrated or anhydrous polycrystalline solids with a metalion–ligand mole ratio of 1 : 2 for divalent ions and of 1 : 3 in the case of trivalent cations. Their coloursdepend on the kind of central ion: pink for Co(II) complex, blue for Cu(II), white for La(III) and violetfor Nd(III) complexes. The carboxylate groups in these compounds are monodentate, bidentate bridgingor chelating and tridentate ligands. Their thermal decomposition was studied in the range of 293–1173 K.Hydrated complexes lose crystallization water molecules in one step and form anhydrous compounds,that next decompose to the oxides of respective metals. 3,4 – Dimethoxybenzoates of Co(II) is directlydecomposed to the appropriate oxide and that of Nd(III) is also ultimately decomposed to its oxide butwith the intemediate formation of Nd 2 O 2 CO 3. . The magnetic moment values of 3,4–dimethoxybenzoatesdetermined in the range of 76–303 K change from 4.22 μ B to 4.61 μ B for Co(II) complex , from 0.49 μ Bto 1.17 μ B for Cu(II) complex , and from 2.69 μ B to 3.15 μ B for Nd(III) complex.