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Two novel symmetrical Schiff base ligands, H 2 L 1 and H 2 L 2 , with tetradentate N 2 O 2 and pentadentate N 3 O 2 coordinating sites were prepared by the reaction of the aldehyde 2-methyl-7-formyl-8-hydroxy-quinoline with 1,3-diaminopropane or diethylenetriamine, respectively, in the molar ratio 2:1. Cu(II), Ni(II), Co(II), Mn(II), Fe(III) and VO(IV) complexes of both ligands were synthesized. The ligands and their metal complexes were characterized by elemental analyses, IR, UV-Vis, ESR, NMR and mass spectra and also by magnetic moment measurements. Both ligands behave as tetradentate ones when coordinating metal cations. The ligand H 2 L 1 has a smaller cavity than the ligand H 2 L 2 , thus the former ligand yielded mononuclear products, through chelation of one ligand molecule to a metal cation, while the latter ligand yielded binuclear products, through the coordination of two metal cations to two ligand molecules. Each of the Fe(III) cations was coordinated to three halves of both ligand molecules yielding also a mononuclear product with ligand H 2 L 1 and a binuclear product with ligand H 2 L 2 . Either mononuclear or binuclear complex molecules link together forming polymeric chains. The mononuclear and binuclear complex forms were well manifested in the ESR spectra of the vanadyl complexes. The polymeric structures of the metal complexes led to an enhanced decrease of their magnetic moments through antiferromagnetic exchange between neighbouring metal cations.

A new series of hydrazone P-diketone organic ligands were prepared: 3-(2-acetylpheny1hydrazone)pentane-2,4-dione (2-APHA), 2-(2-acetylpheny1hydrazone)-1-phenyl-1,3-butane dione (2-APHB), 2-(2-acetylpheny1hydrazone)-1,3-diphenyl-1,3-propane dione (2-APHDB), 3-(2-acetylphenylhydrazone) 1,1,1-trifluoropentane-2,4-dione (2-APHTA) and 2-(2-acetylpheny1hydrazone)-5,5-dimethyl-1,3-cyclohexane dione (2-APHDm). The step formation constants of their 1:l and 1:2 rare-earth complexes were determined at 30°C by pH titration in 75% (v/v) dioxane-water solvent. The ionization constant of ligands were also measured. A curious odd-even stability differential was apparent in the (2-APHDm) ligand with the heavier rare earths Gd-Lu. The differential was apparent in both log K , and log P values and may be sufficient to cause reversal of the usual ion-exchange elution sequence. On a prCparC une nouvelle skrie de ligands organiques dCrivts d'hydrazones de P-dicttones : (acCtyl-2 phCny1hydrazone)-3 pentanedione-2,4 (2-APHA), (acCtyl-2 phCny1hydrazone)-2 phtnyl-1 butanedione-1,3 (2-APHB), (acttyl-2 phCny1hydrazone)-2 diphCnyl-1,3 propanedione-1,3 (2-APHDB), (acCtyl-2 phtny1hydrazone)-3 trifluoro-1 , 1 , 1 pentanedione-2,4 (2-APHTA) et (acCtyl-2 phCny1hydrazone)-2 dimkthyl-5,5 cyclohexanedione-1,3 (2-APHDm). Operant a 30°C, dans un mClange dioxanneleau i 75% (v/v), on a dCterminC les constantes de formation par ttape de leurs complexes I: 1 et 1:2 avec des terres rares. On a aussi mesurC la constante d'ionisation des ligands. On a determink qu'il existe une curieuse de stabilitt diffkrentielle dans les complexes pair et impair du ligand 2-APHDm avec les terres rares plus lourdes de la strie Gd a Lu. On peut remarquer les differences tant dans les valeurs du log K , que du log P et ces differences sont telles qu'elles peuvent &tre suffisantes pour renverser la stquence habituelle d'Clution lors de l'tchange d'ions.[Traduit par la revue] P-Diketones are well-known chelating agents, capable of forming stable complexes with metal ions. Lanthanide Pdiketones have also been found to have wide application (2), including chromatographic separation of the lanthanide series (3). Azo compounds are also used as complexing agents (4), and the combination of azo compounds and P-diketones are good ligands (5). The chelation between similar ligands and lanthanide metal has been studied (6, 7).The coupling product of the diazonium salt of 2-aminoacetophenone with-different P-diketones such as acetylacetone, benzoylacetone, dibenzoyl methane, trifluoroacetylacetone, and 5,5-dimethylcyclohexane-1,3-dione (dimedone) produces a series of 3-(2-acetylphenylhydrazone)diketone ligands. T h e present study determined the acid dissociation constants of these ligands and the formation constants of their trivalent lanthanide complexes. The structure and basicity effects of the ligands on the stability of the formed complexes are discussed and some correlations attempted. These complexing agents may be useful in the separation of the lanthanides. Experimental (i) Ma...

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