Easily Accessible Rare-Earth-Containing Phosphonium Room-Temperature Ionic Liquids: EXAFS, Luminescence, and Magnetic Properties

A range of liquid rare earth chlorometallate
complexes with the
alkyl-phosphonium cation, [P666 14]+,
has been synthesized and characterized. EXAFS confirmed the predominant
liquid-state speciation of the [LnCl6]3– ion in the series with Ln = Nd, Eu, Dy. The crystal structure of
the shorter-alkyl-chain cation analogue [P4444]+ has been determined and exhibits a very large unit cell. The luminescence
properties, with visible-light emissions of the liquid Tb, Eu, Pr,
and Sm and the NIR emissions for the Nd and Er compounds, were determined.
The effective magnetic moments were measured and fitted for the Nd,
Tb, Ho, Dy, Gd, and Er samples.