BLUE LUMINESCENT ORGANOALUMINUM COMPOUNDS - AL-2(CH3)(4)(7-AZAIN)(2),AL-2(CH3)(2)(7-AZAIN)(4), AL-2(CH3)(OCH(CF3)(2))(3)(7-AZAIN)(2), (MU-OCH(CF3)(2))(CH3)(7-AZAIN)(2)(OCH(CF3)(2))(2), AL-3(MU(3)-O) (CH3)(7-AZAIN)4(OCH(CF3)2)2, AND AL-4(MU(3)-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. T wo new 7-azaindole complexes, Al-2(CH3)(4)(7-azain)(2) (1) and Al-2(CH 3)(2)(7-azain)(4) (2) have been isolated and structurally characterize d. Both complexes display a blue luminescence upon irradiation by UV l ight. The introduction of alcohol and water into the reaction of 7-aza indole with Al(CH3)(3) resulted in the formation of several dinuclear and polynuclear complexes which also emit in the blue region. The crys tal structures of three new complexes from these reactions, 2(mu-OCH(C F3)(2))(CH3)(7-azain)(2)(OCH(CF3)(2))(2) (3) Al-3(mu(3)-O)(CH3)(7-azai n)(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., br idging two aluminum ions. The quantum yields for compounds 2 and 4 wer e 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 s tabilizing the ligand and promoting the blue luminescence.