Synthesis, characterization, and properties of four lanthanide-based coordination polymers with mixed ligands of 4-((4′-carboxybenzyl)oxy)benzoic acid and oxalic acid

A series of lanthanide-based coordination polymers (Ln2(CBOB)2(OX)·H2O, where Ln = Gd (1), Eu (2), Pr (3), and Tb (4); CBOB = 4-[(4′-carboxybenzyl)oxy]benzoate; OX = oxalate), were obtained from the reaction of H2OX, H2CBOB, and Ln(NO3)3 with the metal salts. Single-crystal measurements show that both 1 and 2 feature unique 3-D structures with the [Ln(COO)n(C2O4)m] layers connected by CBOB ligands. Moreover, 1, 3, and 4 are antiferromagnetic and 2 and 4 display obvious luminescence emission peaks. Furthermore, quantum Monte Carlo (QMC) simulations and the experimental results reveal that the magnetic coupling parameters of adjacent Gd(III) ions in 1 are −0.026(2) and −0.0069(3) cm─1.