Physico-chemical properties of Nd(III) and Er(III) complexes with some biological buffer ligands

The new Nd(III) and Er(III) complexes with the zwitterionic buffer ligands N-tris[hydroxymethyl]methyl-3-aminopropane-sulfonic acid sodium salt (NaTAP S) and 3-[N,N-bis(2-hydroxyethyl)amino]-2-hydroxypropanesulfonic acid sodiu m salt (NaDIPSO) have been prepared and characterized by IR, DTA, TG, mass, elemental analyses and electrical conductivity measurements. The Nd(III) c omplexes may be formulated as [Nd(DIPSO)(2)(H2O)(n)]NO3 . mH(2)O, where n = 1 and m = 1 for NaDIPSO as ligand while n = 2 and m = 0 for NaTAPS as liga nd, [Nd(TAPS)(2)(H2O)(n)]NO3. The Er(III) complexes may be described as [Er (DIPSO)(2)(H2O)n]Cl . mH(2)O, where n = m = 2 for NaDIPSO as ligand while n = 2 and m = 0 for NaTAPS as ligand. Thermogravemetric studies show that th e Er(III) complexes are thermally more stable than the Nd(III) complexes. T he electrical conductivity of DMF solutions of these complexes indicate 1:1 electrolytic behavior.