Syntheses and structures of new blue luminescent B(III) and Al(III) complexes: BPh2(acac-azain) and Al(CH3)(acac-azain)2, acac-azain=1-N-7-azaindolyl-1,3-butanedionato

A novel blue luminescent ligand, 1-N-7-azaindolyl-1,3-butanedione (acac-azainH), has been synthesized and characterized structurally. The acac-azainH has a diketone structure in the solid state. The diketone form of acac-azainH is also dominant in solution. The acac-azainH molecule reacts readily with BPh3 and Al(CH3)3 to form chelate complexes BPh2(acac-azain) (1) and Al(CH3)(acac-azain)2 (2), respectively. The structure of 1 was determined by a single-crystal X-ray diffraction analysis. The acac-azainH molecule and compounds 1 and 2 are all blue luminescent but the luminescent efficiency is poor. In solution, compound 2 appears to exist in two isomeric forms.