Complexes of Rare Earth Metals with Bromine-Substituted (Benzoxazolyl)Naphtholate Ligands as Emissive Materials

Abstract

A series of complexes [Ln(Np^BrOON)₃]₂ (Ln = Nd, Eu, Gd, Yb) were synthesized by the reaction of the corresponding lanthanide silylamides with 2-(2-benzoxazol-2-yl)-7-bromo-3-naphthol. The structure of the initial phenol, Eu and Yb complexes was established using X-ray diffraction analysis, which showed that the resulting compounds have a centrosymmetric dimeric structure. All the obtained complexes in the solid state upon excitation by light with a wavelength of 365 nm revealed ligand-centered photoluminescence (PL) in the visible region of 450-700 nm. The complexes of Nd and Yb in addition exhibit the metal-centered emission in the near-infrared (NIR) region of high intensity.