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)(CH 3 ) ( 1 ), Al(7-azain) 3 (7-azain-H) ( 2 ), and Al(7-azain)(7-azain-H)(OCH(CF 3 ) 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. 1 H 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 (λ max = 430−450 nm) upon irradiation by UV light. 27 Al solution and solid-state NMR studies on all three compounds were performed. The data of 27 Al solution NMR are in agreement with those of 27 Al solid NMR. Quadrupole parameters of 27 Al in all three compounds have been obtained.