Lanthanide complexes of 2,6-dihydroxybenzoic acid: synthesis, crystal structures and luminescent properties of [nBu(4)N](2)[Ln(2,6-dhb)(5)(H(2)O)(2)] (Ln = Sm and Tb)

Abstract

Lanthanide complexes of 2,6-dihydroxybenzoic acid (2,6- Hdhb), namely [nBu4N]2[Ln(2,6-dhb)5(H2O)2] [Ln = Sm (1) and Tb (2)], were synthesized and their crystal structures determined by single-crystal X-ray diffraction studies. The 2,6- dhb− ligand coordinates to the lanthanide cations through the carboxylate group in a monodentate or bidentate chelating coordination mode. The compounds were further characterised using IR, Raman, 1H and 13C NMR spectroscopy and elemental analysis. Photoluminescence measurements were performed on both compounds. In particular, the terbium complex 2 shows intense photoluminescence both in the solid state and in ethanolic solution. Compound 2 also exhibits triboluminescence.