Abstract
27Al NMR spectra of Al3+ ions complexed with cyclo-tri-μ-imido triphosphate anions have been measured. Successive complexations to form mono-, di-, and tridentate complexes have been confirmed by an additivity rule found in the relationship between the number of coordination atoms and the 27Al chemical shift value of respective complex. The peak area ratio calculated for tridentate complexes to didentate complexes remains constant(=ca. 0.3) irrespective of the change in the concentrations of Al3+ and the ligand anions, indicating that the successive complexation is intramolecular reaction. A further deconvolution of the 27Al spectra revealed direct coordination of Al3+ions with nitrogen atoms as well as non-bridging oxygen atoms belonging to the ligand molecules.
