One-dimensional lanthanide selenite-carboxylate compounds: Synthesis, crystal structure and properties

Five new lanthanide selenite-carboxylate compounds, namely Ln(SeO3)(2,6-pdcH)(H2O)2 (Ln = La (1), Ce (2), Pr (3), Nd (4), Nd0.86La0.14 (5), 2,6-pdcH2 = pyridine-2,6-dicarboxylic acid) have been hydro-/solvothermally synthesized and structurally characterized. They are isostructural to one another and the structures feature one-dimensional chain along the a axis composed of alternating four-membered rings of [Ln2O2] and [LnSeO2] inter-chain hydrogen bonding interactions among the coordinated water molecules, carboxylate groups, and selenites lead to two-dimensional architectures parallel to the ab plane, which are further connected into a three-dimensional supramolecular framework via π–π interactions among parallel pyridine rings of the 2,6-pdcH ligands in adjacent chains. Their thermal and photoluminescent properties have been investigated.