The structures of complex anions, [Al(edta)]- and [Ga(edta)]- (H4edta = ethylenediaminetetraacetic acid), were investigated both in the solid state (X-ray crystallography) and in solution (1H and 13C NMR). Two complexes, (NH4)[Al(edta)]·2H2O (1) and (NH4)[Ga(edta)]·2H2O (2), are isostructural in the solid state. In both metal complexes, the central metal atoms are coordinated by six donor atoms (N2O4) in distorted octahedral coordination geometries in which two nitrogen atoms and two oxygen atoms of two acetate groups occupy the equatorial positions, and the axial positions are occupied by two oxygen atoms of two acetate groups. The 1H and 13C NMR spectra of 1 and 2 showed that acetate groups undergo rapid interchanges between the axial and equatorial positions in solution, its rate in D2O being much faster than that in dimethyl sulfoxide(dmso)-d6 for each complex, and its rate for 1 being slower than that for 2. Based on the NMR spectra, the structures of complex anions [Al(edta)]- and [Ga(edta)]- in solution are concluded to be the same as those in the solid state.

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A new N3-O2 pentadentate ligand, H-BHPT, was synthesized. Hydrochloric acid salts of Br-BHPT, Cl-BHPT, CH3O-BHPT and CH3-BHPT, having Br-, Cl-, CH3-and CH3O-substituents at the para position of the phenol hydroxyl group of H-BHPT were synthesized. Hydrochloric acid salts of 3OH-BHPT and 4OH-BHPT, having different position of the phenol hydroxyl group of H-BHPT were also synthesized. The synthesis of each ligand was confirmed by C. H. N. atomic analysis and 1 H NMR, 13 C NMR, UV-visible, and mass spectra. The calculated proton dissociation constants (logKn H ) of the phenol hydroxyl group and secondary amine group of the synthesized N3-O2 ligands showed five steps of the proton dissociations. The order of the overall proton dissociation constants (logβp) of the ligands was Br-BHPT < Cl-BHPT < H-BHPT < CH3O-BHPT < CH3-BHPT. The order agreed with that of Hammett substituent constants (δp). However, dissociation steps of 3OH-BHPT were four and that of 4OH-BHPT was three. The calculated stability constants (logKML) between the ligands and transition metal ions agreed with the order of logβp values of the ligands. The order of the stability constants between the transition metal ions with the synthesized ligands was Co(Ⅱ) < Ni(Ⅱ) < Cu(Ⅱ) > Zn(Ⅱ) > Cd(Ⅱ) > Pb(Ⅱ). The order agreed well with that of the Iriving-Williams.

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