Syntheses, crystal structure and magnetocaloric effect of [Gd(PDOA)(NO3)(H2O)2]n

Abstract The coordination polymer [Gd(PDOA)(NO 3 )(H 2 O) 2 ] n ( 1 ) (PDOA =  o -phenylenedioxydiacetato) has been prepared and spectroscopically and structurally characterized. Its crystal structure is formed of a ribbon-like arrangement of Gd(III) atoms linked by bridging carboxylate groups and placed at the cusps of fused triangles with Gd⋯Gd distances of about 6.1 A. The Gd(III) central atoms exhibit decacoordination by oxygen atoms from hexadentate PDOA ligands with chelating and bridging functions, a chelating nitrato ligand and two aqua ligands. Intra- and intermolecular hydrogen bonds of the O H⋯O and C H⋯O types contribute to the stability of the structure. The temperature dependence of the magnetic susceptibility revealed weak magnetic interactions among Gd(III) ions which may be attributed to dipolar coupling. Investigation of the magnetocaloric effect gives an estimate of the maximum value of isothermal change of magnetic entropy –ΔS m  ≈ 35 J kg −1  K −1 which suggests that 1 can be a good material for magnetic cooling at low temperatures.