Syntheses, structures, solution, and solid-state 27Al NMR studies of blue luminescent mononuclear aluminum complexes:: Al(7-azain)2(7-azain-H)(CH3), Al(7-azain)3(7-azain-H), and Al(7-azain)(7-azain-H) (OCH(CF3)2)2 (7-azain-H=7-azaindole)

Three novel mononuclear aluminum complexes, Al(7-azain)(2)(7-azain-H)(CH3) (1), Al(7-azain)(3)(7-azain-H) (2), and Al(7-azain)(7-azain-H)(OCH(CF3)(2))(2) (3), where 7-azain-H = 7-azaindole, have been synthesized and fully characterized structurally. The aluminum ion in all three compounds is in a tetrahedral environment. The neutral 7-azaindole ligand is coordinated to the aluminum center through the indole nitrogen site, resulting in a zwitterion form for all three compounds in the solid state. H-1 NMR studies established that in solution these compounds are dynamic, caused by an interconversion between the zwitterion isomer and a nonzwitterion isomer. All three compounds produce a blue light (lambda(max) = 430-450 nm) upon irradiation by UV light. Al-27 solution and solid-state NMR studies on all three compounds were performed. The data of Al-27 solution NMR are in agreement with those of Al-27 solid NMR. Quadrupole parameters of Al-27 in, all three compounds have been obtained.