Template Synthesis of Lanthanide (Pr, Nd, Gd) Coordination Polymers with 2-Hydroxynicotinic Acid Exhibiting Ferro-/Antiferromagnetic Interaction

Lanthanide coordination polymers were synthesized from Pr(III), Nd(III), and Gd(III) salts; 2-hydroxynicotinic acid (Hnica); and MnSO4·H2O under hydrothermal conditions. In the absence of (CH3)3CCOONa, 1D polymers with an infinite Ln(III)−O−Ln(III) chain structure, [Pr(Hnica)(H2O)2SO4]n (1), [Nd(Hnica)(H2O)2SO4]n (2), and [Gd(Hnica)(H2O)2SO4]n (3), were generated. When (CH3)3CCOONa was added to the synthetic systems, 2D coordination polymers {[Pr3(Hnica)6(H2O)9]·3H2O·SO4·NO3}n (4), {[Nd3(Hnica)6(H2O)9]·3H2O·SO4·NO3}n (5), and {[Gd(Hnica)2(H2O)2]ClO4·H2O}n (6) were obtained. Complexes 4 and 5 both exhibit Kagomé lattice structure, while 6 displays a rhombic grid structure. All complexes were characterized by elemental analysis, IR spectra, UV−vis spectra, and X-ray single-crystal diffraction. The variable-temperature magnetic susceptibility studies reveal ferromagnetic interactions between gadolinium(III) ions in 3 and 6 and antiferromagnetic interactions in 1, 2, 4, and 5.