Jean-Claude Bunzli - FT-IR and fluorometric investigation of rare-earth and metal ion solvation .16. Solid state and solution study of acetonitrile-coordinated lanthanide solvates [Ln(CH3CN)(9)](AlCl4)(3)

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  Bunzli,J.C.G., MilicicTang,A. Inorganica Chimica Acta  1996 252 (1-2) 221-228

  Abstract: The CH3CN coordinated lanthanide   solvates [Ln(CX(3)CN)(9)](AlCl4)(3) have been studied by means of   luminescence (X = H, D; Ln = Eu, Tb) and FT-IR spectroscopy (X =   H; Ln = La, Nd, Gd, Er, Lu). High resolution luminescence   spectra, recorded at 77 K, of the [Eu(CH3CN)(9)](AlCl4)(3)   microcrystalline compound, show the Eu-III ion located in one   unique coordination site with a local symmetry close to D-3h. The   same local structure is preserved in Eu-doped La and Gd solvates,   pointing to an isostructural series of compounds. The lifetime of   the Eu(D-5(0)) level amounts to 5.07 ms in the deuterated   solvate. The tricapped trigonal prismatic geometry is lost in   0.01 M solutions in anhydrous acetonitrile and propylene   carbonate. Analysis of the D-5(0) <-- F-7(0) transition points   to the presence of at least two different species in equilibrium.   Vibrational spectra evidence a sizable Ln-acetonitrile   interaction substantiated by the shifts of the nu(2) and nu(3) +   nu(4) vibrations which increase linearly with the increase in   electronic density of the lanthanide ions and which are identical   to those observed for lanthanide perchlorate and nitrate   solutions under the same experimental conditions. This means that   the Ln-acetonitrile interaction is mainly governed by   electrostatic factors. In mixed propylene carbonate-acetonitrile   solutions of [La(CH3CN)(9)](AlCl4)(3) complexes, lanthanum ions   are preferentially solvated by propylene carbonate molecules for   R = [CH3CN](t)/[Ln(III)](t) less than or equal to 50. For R =   100, four acetonitrile molecules are bonded to the lanthanum ion

  Address (URL): WOS:A1996VZ07900026