0000000000376773
AUTHOR
Sixto Domínguez
Dimer complexes of 2,4-toluenediamine-N,N,N′,N′-tetraacetic acid (2,4-TDTA) with copper(II), nickel(II), cobalt(II), zinc(II) and manganese(II). Studies in aqueous solution and solid state. X-ray crystal structures of Na4[Ni2(2,4-TDTA)2]·15H2O and Na4[Cu2(2,4-TDTA)2]·20H2O
Abstract Potentiometric investigations in aqueous solution at 25°C and ionic strength 0.1 mol dm−3 KCl show that 2 2,4-toluenediamine-N,N,N′N′-tetraacetic acid (2,4-TDTA) forms with Cu(II), Ni(II), Co(II), Zn(II) and Mn(II) the following complexes (ligand, H4L): monomers [MH2L], [MHL]− and [ML]2−; dimers [M2HL2]3− and [M2L2]4−; with excess of ligand [MH2L2]4−, [MHL2]5− and [ML2]6− (Cu(II), Ni(II) and Zn(II)) and with excess of metal [M2HL]+ (Ni(II), Co(II)and Mn(II) and [M2L] (Cu(II)). The formation constants of the complexes have been determined. The species distribution diagrams indicate that a concentrated solution with a ligand:metal ratio 1:1 at pH 6 is suitable for the synthesis of cr…
2,2′-Oxydiacetato-bridged complexes containing Sm(III) and bivalent cations. Synthesis, structure, magnetic properties and chemical speciation
Abstract Heterometallic compounds containing Sm(III), bivalent cations M (M = Cu, Ni, Co, Mn, Ca, Mg), and 2′,2′-oxydiacetate (oda) as connecting ligand have been prepared and characterized. The complexes can be formulated as [Sm 2 M 3 (oda) 6 ] · xH 2 O. The structure of [Sm 2 Cu 3 (oda) 6 (H 2 O) 6 ] shows the presence of the Sm(III) coordinated by six carboxy and three ether oxygen atoms, and the Cu(II) cation bonded to four carboxy oxygens and two molecules of water. An open 3D framework is observed, containing large hexagonal channels. At room temperature, the polynuclear complexes behave as built by magnetically isolated paramagnetic ions, but at low temperatures, very weak antiferrom…
Synthesis, crystal structure, thermal and magnetic properties of [Mn(H2O)6][Cu(pdta).2H2O (pdta= 1,3-propylenediamine-N,N,N',N'-tetraacetate
[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 …