LINKAGE ISOMERISM IN AL-III COMPLEXATION WITH AZO-SYSTEM MULTIDENTATELIGANDS

The ligand 5-chlorophenyl)azo]-8-hydroxyguinoline-5-sulfonate coordina tes to Al-III first with the 8-quinolinol moiety to form a 1:1 yellow N,O-bidentate complex through a fast process within 35 s. In the pseud o-first-order kinetic conditions, the rate constant of the fast proces s depends on the Al-III concentration and in this process the complexa tion occurs mainly via a pathway of the reaction containing the specie s AlOH2+. Then, the yellow complex slowly changes to a red O,N,O-tride ntate complex within ca 60 min. The rate constant of the slow process is independent of an experimental Al-III concentration, thus showing a linkage isomerism via an intramolecular rearrangement. Copyright (C) 1996 Elsevier Science Ltd