Hydrothermal synthesis, crystal structure and properties of two new coordination polymers structured by two mixed ligands and strict quadrangular {Ln3}8 Units (Ln = Er and Ho)

Two new three-dimensional coordination compounds formulated as [Ln3(IN)2(bdc)3.5(H2O)3]·0.5H2O (Ln = Er 1, Ho 2), where HIN = isonicotinic acid and H2bdc = 1,4-benzenedicarboxylic, have been obtained by hydrothermal assemble of Ln2O3 (Ln = Er 1, Ho 2), HIN and H2bdc. Structural analysis shows that Ln3+ ions are connected by both ligands IN− and bdc2 − in 1 and 2. IN− links two adjacent {Ln3} units along b axis, while bdc2 − connects eight {Ln3} units along different directions, which leads to an interesting strict {Ln3}8 quadrangular in 3D open frameworks of 1 and 2.