Analytical Sciences


Abstract − Analytical Sciences, 19(8), 1177 (2003).

Performance ofTris(2-methyl-8-quinolinolato)aluminum as FluorescentAnionophore
Akio YUCHI,  HiroakiHIRAMATSU, Miyuki OHARA, and Nayumi OHATA
Nagoya Institute of Technology, Gokiso,Showa, Nagoya 466-8555, Japan
An X-ray crystallographic study demonstratedthat the tris complex of Al3+ with 2-methyl-8-quinolinol (Hmq),[Al(mq)3], had a discrete octahedral geometry in a meridionalconfiguration with respect to mq-; the Al-N bonds wereappreciably elongated. In organic solvents, the complex reacted with waterto give a lower species of a µ-oxo dimer,[Al2O(mq)4], and a protonated ligand, depending onthe concentrations of water and of excess ligand. None of Cl-,Br-, I-, ClO4-, andCH3COO- showed any reactions with[Al(mq)3]. The anions having high affinities toAl3+, such as H2PO4- andF-, replaced all the ligand. The anion having a lower affinity,HSO4-, exclusively formed a mixed-ligand complex of[Al(mq)2HSO4], which had a more intense fluorescencethan the others. In contrast, the corresponding 8-quinolinol (Hq) complex,[Alq3], showed no reactions with any anions.