Coordination complexes of trivalent non-transition metal ions

Lathaxride(III) complexes of three potentially heptadentate Schiff base ligands were prepared by addition of lanthanide(III) salts to a solution containing a slight excess of ligand in the presence of poorly coordinating chloride ions or strongly coordinating nitrate ions. The complexes La(hatren), La(datren)(CH₃0H) and La(trac) were isolated in the presence of chloride ions, and were found to have the ligand bound in a hexadentate or heptadentate fashion. We were unable to isolate analogous complexes with the heavier lanthanides (Ln = Pr, Nd, Gd, Dy, Yb, Lu). The complexes Ln(H₃L)(NO₃)₃ (Ln = La, Pr, Nd, Gd, Dy, Yb; H₃L = H₃hatren, H₃datren) and Ln(H₃trac)(NO₃)₃ (Ln = Pr, Nd, Gd, Dy, Yb) were isolated in the presence of nitrate ions, and were found to have the Schiff base ligand bound in a tridentate fashion ( where H₃datren = tris(2'-hydroxy-4',5'-dimethylacetopheniminoethyl)amine; H₃trac = tris(3-aza-4-methylhept-4-ene-6-one)amine; and H₃hatren = tris(2'-hydroxyacetophenirninoethyl)amine) All products were characterized by infrared and mass spectroscopy, and by elemental analysis. ¹H-NMR spectroscopy indicated that the complexes were solution labile and dissociated in DMSO to yield free ligand and solvated lanthanide(III) ions. The crystal structure of Gd(H₃trac)(NO₃)₃ was determined. The gadolinium(III) ion is nine coordinate. H₃trac is bound only through its three oxygen donor atoms, and the nitrate ions are bound in a bidentate fashion to the gadolinium center. Aluminum (III) and gallium(III) complexes of 2-chloromethyl-5-hydroxy-4H-pyran-4-one (Hck) were isolated from a basic aqueous solution. The complexes Al(ck)₃ and Ga(ck)₃ were characterized by ¹H-NMR (CDCI₃), infrared and mass spectroscopy, as well as by elemental analysis. Al(ck)₃ was also characterized by ²⁷Al-NMR in CDCI₃.Science, Faculty ofChemistry, Department ofGraduat