Synthesis, crystal structure, thermal and magnetic properties of [Mn(H2O)6][Cu(pdta).2H2O (pdta= 1,3-propylenediamine-N,N,N',N'-tetraacetate

Abstract

[EN] On mixing concentrated aqueous solutions of pdta, Cu(II) and Mn(II) in the ratio 1:1:1 at pH 4.5, single crystals of the complex [Mn(H2O)6][Cu(pdta)]·2H2O (1) (pdta=1,3-propylenediamine-N,N,N'N'-tetraacetate) were obtained. X-ray structural analysis revealed that in the anion [Cu(pdta)]2- the coordination polyhedron around the Cu(II) ion can be described as a tetragonaly distorted CuN2O4 octahedron, whereas the cation [Mn(H2O)6]2+ can be described as a very regular MnO6 octahedron. Thermogravimetric analysis shows that at 110°C compound 1 loses its eight water molecules yielding the anhydrous compound [MnCu(pdta)] (2). Variable-temperature magnetic susceptibility measurements indicate that no magnetic interactions are present in 1 while weak antiferromagnetic interactions occur in 2.