A Agsingle bondLa coordination polymer with metatungstate and 2-pyrazinecarboxylic acid. Synthesis, structure and luminescence

A Agsingle bondLa coordination polymer of metatungstate (H2W12O406 −) and 2-pyrazinecarboxylic acid (L), (H3O)[Ag6La(H2O)6L4(H2W12O40)](1), was synthesized hydrothermally and characterized by elemental analysis, IR spectroscopy, and thermal gravimetric analysis. Single-crystal X-ray analysis reveals that the compound 1 crystallizes in monoclinic system with C2/c space group. In 1 Ag ions are coordinated by H2W12O406 − and 2-pyrazinecarboxylic acid. The linkage of Ag and L creates a AgL polymeric chain extending along b-axis. H2W12O406 − acts as a thirteen-dentate ligand and coordinates to sixteen Ag+ ions of six AgL chains, leading to a three dimensional structure. La3 + ion accepts six carboxyl oxygen atoms of four AgL chains and two water molecules, exhibiting a nearly cube geometry. Photoluminescent emission peak of 1 is observed at 438 nm which is attributed to LMCT or MLCT transition.