Syntheses, structures, and electroluminescence of Ln₂(acac-azain)₄(μ-acac-azain)₂ [acac-azain = 1-(N-7-azaindolyl)-1,3-butanedionato, Ln - Tb(III) and Y(III)]

Two new luminescent lanthanide complexes Ln₂(acac-azain)₄(μ-acac-azain)₂ [acac-azain = 1-(N-7-azaindolyl)-1,3-butanedionato, Ln = Tb(III), 1, Y(III), 2] have been synthesized and structurally characterized. These two dinuclear complexes are isostructural with the two lanthanide ions being bridged by two acac-azain ligands. Each of the two metal ions is further chelated by four oxygen atoms from two acac-azain ligands, resulting in a coordination number eight for each metal ion. 1 displays characteristic Tb(III) emission bands while 2 displays weak blue luminescence attributable to the ligand. Single-layer and double-layer electroluminescent devices for compound 1 were fabricated, where compound 1 doped PVK layer functions as both the emitting layer and the hole transport layer and PBD functions as an electron transport layer (in the double-layer device), demonstrating that compound 1 is a promising green emitter in electroluminescent devices.