Carboxylato-bridged 3D polymeric networks of Gd(III): Synthesis, crystal structure, magnetic property and thermal behavior

Abstract

Two novel polymeric carboxylato-bridged gadolinium(III) complexes of formulae, [Gd 2(fum) 3(H 2O) 4] · 2H 2O ( 1) and [Gd 2(tart) 3(H 2O) 2] · 3H 2O ( 2) (fum, fumarate dianion; tart, tartrate dianion) have been synthesized and characterized by single crystal X-ray diffraction studies, low-temperature magnetic measurements and thermal studies. The structure determination reveals a 3D network containing nine coordinated Gd(III) ions: for complex 1, the coordination sphere of gadolinium(III) comprises of two water molecules and seven oxygen atoms from fumarate dianions and for complex 2, a water molecule and eight oxygen donors from tartrate dianions. Variable-temperature magnetic susceptibility measurement reveals the existence of a weak antiferromagnetic coupling through the gadolinium ions. The best-fit parameters for complex 1, assuming a simplified structural model led to J = −0.0076 cm −1, g = 2.0, R = 2 × 10 −5 whereas for complex 2 the double-layered structure inside the 3D network impedes the possibility to calculate the J value(s).