Europium‐Based Ionic Liquids as Luminescent Soft Materials

Abstract

Low melting, highly luminescent: [C3mim][Eu(Tf2N)4] (1), [C4mim][Eu(Tf2N)4], and [C4mpyr]2[Eu(Tf2N)5] are the first lanthanide ionic liquids that do not need stabilization of the liquid state by neutral coligands. They show excellent photophysical properties, such as long lifetimes of luminescence at large EuIII concentration, small line width, and high color purity (see emission spectrum of 1 and photograph of a sample under UV light).