Four novel blue/green luminescent compounds, Zn(2-py-in)2(THF) (1), BPh2(2-py-in) (2), Be(2-py-in)2 (3), and BPh2(2-py-aza) (4), where 2-py-in = 2-(2-pyridyl)indole and 2-py-aza = 2-(2-pyridyl)-7-azaindole, have been synthesized and fully characterized. The 2-py-in ligand and 2-py-aza ligand in the new compounds are chelated to the central atom. Compounds 2−4 are air stable and readily sublimable, with a melting point above 250 °C. In the solid state, compounds 1−4 have an emission maximum at λ 488, 516, 490, and 476 nm, respectively. The structures of compounds 2 and 4 are similar. The blue shift of emission energy displayed by compound 4, in comparison to that of 2, is attributed to the presence of an extra nitrogen atom in the 2-py-aza ligand as confirmed by ab initio calculations on compounds 2 and 4. Electroluminescent devices of compounds 3 and 4 were fabricated by using N,N ‘-di-1-naphthyl-N,N ‘-diphenylbenzidine (NPB) as the hole transporting layer, Alq3 (q = 8-hydroxyquinolato) as the electron transporting layer, and compound 3 or 4 as the light emitting layer. At 20 mA/cm2 the EL device of 3 has an external efficiency of 1.06 cd/A while the EL device of 4 has an external efficiency of 2.34 cd/A, demonstrating that compounds 3 and 4 are efficient and promising emitters in electroluminescent devices.

Three new complexes BPh 2 (mqp) (1), Al(CH 3 )(mqp) 2 (2), and Al(mqp) 3 (3) have been synthesized and characterized, where mqp ) 2-(4′-methylquinolinyl)-2-phenolato. The mqp ligand in compounds 1 and 2 act as a chelate ligand, while in compound 3 it acts as both a chelate ligand and a terminal ligand. The boron center in 1 has tetrahedral geometry, while the aluminum ion in 2 and 3 has trigonal-bipyramidal geometry. In CH 2 Cl 2 solution, these compounds emit a green, a green-blue, and a whitish blue color (λ ) 514, 515, 497 nm), respectively, when irradiated by UV light. In the solid state, these three compounds emit a green, a blue, and a whitish blue color, respectively (λ ) 520, 474, 500 nm). Electroluminescent devices using compound 3 as an emitter have been fabricated.