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Dalton Transactions

The international journal for inorganic, organometallic and bioinorganic chemistry




Paper

Dalton Trans., 2009, 5137 - 5147, DOI: 10.1039/b822322j


Synthesis, structures and characterisations of truly homoleptic acetonitrile Ln3+ complexes in solid state and in solution

Gabriella Bodizs, Ines Raabe, Rosario Scopelliti, Ingo Krossing and Lothar Helm


Total halide abstraction from LnCl3 by Ag[Al(OC(CF3)3)4]/CH3CN has been confirmed for a series of lanthanide metal ions by the structural characterization of [Ln(CH3CN)n][Al(OC(CF3)3)4]3 (n = 9, Ln3+ = Nd, Eu, Gd, Dy; n = 8, Ln3+ = Tm) complexes. Evidence for the very low coordinating ability of the [Al(OC(CF3)3)4]- anion towards Ln3+ ions is provided in the solid state (X-ray, IR and Raman spectroscopy) and in anhydrous acetonitrile solution (conductivity, EPR and NMR measurements). In the solid state homoleptic nine-coordinated acetonitrile species are characteristic for lanthanides for the beginning (Nd) and the middle (Eu, Gd, Dy) of the Ln series, with a mono-capped square antiprismatic arrangement of the N donor atoms around the metal centres; while for those from the end of the series (Tm) eight-coordinated species are representative with a square antiprismatic arrangement. In anhydrous acetonitrile solution, conductivity measurements revealed 3:1 electrolyte types for all compounds. EPR and 19F NMR line broadening measurements attest lanthanide complexes free of any coordinating [Al(OC(CF3)3)4]- anion.

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