Blue luminescent organoaluminum compounds:: Al2(CH3)4(7-azain)2, Al2(CH3)2(7-azain)4, Al2(CH3)(OCH(CF3)2)3(7-azain)2, Al2(μ-OCH(CF3)2)(CH3)(7-azain)2(OCH(CF3)2)2, Al3(μ3-O) (CH3)(7-aZain)4(OCH(CF3)2)2, and Al4(μ3-O)2(7-azain)6(OCH(CF3)2)2 (7-azain equals deprotonated 7-azaindole)

The reactions of 7-azaindole with Al(CH3)(3) have been investigated. Two new 7-azaindole complexes, Al-2(CH3)(4)(7-azain)(2) (1) and Al-2(CH3)(2)(7-azain)(4) (2) have been isolated and structurally characterized. Both complexes display a blue luminescence upon irradiation by UV light. The introduction of alcohol and water into the reaction of 7-azaindole with Al(CH3)(3) resulted in the formation of several dinuclear and polynuclear complexes which also emit in the blue region. The crystal structures of three new complexes from these reactions, Al-2(mu-OCH(CF3)(2))(CH3)(7-azain)(2)(OCH(CF3)(2))(2) (3) Al-3(mu(3)-O)(CH3)(7-azain)(4)(OCH(CF3)(2))(2) (4), and Al-4(mu(3)-O)(2)(7-azain)(6)(7-OCH(CF3)(2))(2) (5), have been determined by X-ray diffraction analyses. The 7-azaindole ligand in compounds 1-5 has the same bonding mode, i.e., bridging two aluminum ions. The quantum yields for compounds 2 and 4 were determined to be 0.54 and 0.31, respectively, relative to that of 9,10-diphenylanthracene in cyclohexane. The emission lifetime for these compounds is in the order of 10-100 ns. Molecular orbital calculations using Gaussian 94 methods on the neutral free ligand (7-azainH), the deprotonated ligand (7-azain(-)), and compound 1 were performed, which revealed that the aluminum ions in the complexes play a key role in stabilizing the ligand and promoting the blue luminescence.