New luminescent 10-oxybenzoquinolate complexes of rare earth metals

A series of Sc, Y, Ce, Pr, Nd, Sm, Eu, Gd, Tb, Ho, Er, Tm and Yb complexes with oxybenzoquinoline ligands (BQ) was synthesized by the reactions of 10-hydroxybenzo[h]quinoline with cyclopentadienides or tris(trimethylsilyl)amides of rare earth metals. The structure, as well as the photo- and electroluminescent (PL, EL) properties of these complexes in solutions and solid state were studied. In solutions, complexes of sodium and lanthanides exhibit double peaked ligand-centered PL of enol and keto forms of BQ with a quantum yield of 1%–8%. In the solid state the complexes of Sm, Eu, Ho, Nd, Er, and Yb along with the ligand-centered PL also exhibit a moderate-intensity metal-centered PL which is characteristic of the corresponding Ln3+ ions. Sc(BQ)3 complex shows bright green EL which has intensity comparable to the best results observed for scandium complexes with other organic ligands.