NEW MONONUCLEAR LANTHANIDE(III) MACROCYCLIC POLYMERIC COMPLEXES WITH THE 1,5,9,13-TETRAAZACYCLOHEXADECANE LIGAND: THEIR MAGNETIC STUDIES AND SEMIEMPIRICAL CALCULATIONS

Abstract

Novel mononuclear lanthanide polymeric complexes are formed with Nd(III), Eu(III), Gd(III), Tb(III), Er(III) and Lu(III) nitrates and the 1,5,9,13-tetraazacyclohexadecane ligand. These compounds were characterized by elemental and thermal analysis, IR, EPR, ¹H and ¹³C NMR spectroscopies and magnetic susceptibility at variable temperature. The molecular weight of the compounds was determined by gel permeation chromatography, the results of which 6272 are 6120 and 4121 g/mol for Nd(III), Gd(III) and Er(III) compounds, respectively. The structures for the monomeric unit and the polymers were calculated by the force—field method. Each lanthanide compound showed specific and unusual magnetic properties which were associated with the particular arrangement of the elemental units in each polymer.