Sergio Giardino

Citation:

Giardino, S, Vicentini G, Isolani PC.  1997.  ``Synthesis and characterization of lanthanide picrate complexes with tripiperidinophosphine oxide''. J. Alloys Comp.. 249(1-2):91-93.

Abstract:

Compounds with the general formula Ln(pic)3·2tpppo (Ln: La-Lu, Y; pic=picrate; tpppo=tripipendinophosphine oxide) were synthesized by reaction of the hydrated picrates with tpppo in absolute ethanol. IR absorption spectra were interpreted in terms of the coordination of tpppo through the oxygen and picrate anions that are bidentate, coordinated to the central ions through the phenoxo group and one oxygen of an ortho-nitro group. Conductance measurements in acetonitrile solutions show that the complexes behave as non-electrolytes. X-ray powder patterns show only one isomorphous series. Phosphorus-31 NMR showed a signal shift to lower field with relation to the free ligand, showing evidence of bonding through the phosphoryl group. The parameters obtained from the absorption spectrum of the Nd compound indicate that the metal-ligand bonds present some covalent character. The emission spectra of the europium and samarium adducts were determined. The spectrum of the europium compound was interpreted in terms of D2d distorted towards C2v symmetry for the Eu(O)8 chromophore.

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