Complexos de íons lantanídios com hexametilfosforamida - hexafluoroarsenato como ânion não coordenante

Abstract

Coumpounds of general formula I Ln (HMPA)6 I (AsF6) 3 CHMPA = hexamethylphosphoramide, Ln = Y, La - Lu) were prepared from the lanthanide perchlorates. These compounds are stable at room temperature and are soluble in polar solvents such as acetone, acetonitrile, nitromethane and dimethylsulphoxide. Potentiometric and conductometric measurements as well as studies of emission and absorption spectroscopy in the visible, infrared and far-infrared regions were made with the purpose of determining the formulation of these compounds and the nature of their bonds. Conductance measurements in mM solutions in nitromethane and acetonitrile indicates a 1:3 electrolyte and therefore the non-coordinations of the anion. - Potentiometric titration was used to determine AsF6 in these compounds. The vibrational spectra in the infrared region show the bond to be a metal-ligand through the oxygen of the phosphoryl group. Absorption and emission spectra suggest a non-cubic compound with microsymmetry near of D 3h.