Characterization of a Novel Intrinsic Luminescent Room-Temperature Ionic Liquid Based on [P6,6,6,14][ANS]

Intrinsically luminescent room‐temperature ionic liquids (RTILs) can be prepared by combining a luminescent anion (more common) or cation with appropriate counter ions, rendering new luminescent soft materials. These RTILs are still new, and many of their photochemical properties are not well known. A novel intrinsic luminescent RTIL based on the 8‐anilinonaphthalene‐1‐sulfonate ([ANS]) anion combined with the trihexyltetradecylphosphonium ([P6,6,6,14]) cation was prepared and characterized by spectroscopic techniques. Detailed photophysical studies highlight the influence of the ionic liquid environment on the ANS fluorescence, which together with rheological and 1H NMR experiments illustrate the effects of both the viscosity and electrostatic interactions between the ions. This material is liquid at room temperature and possesses a glass transition temperature (Tg) of 230.4 K. The fluorescence is not highly sensitive to factors such as temperature, but owing to its high viscosity, dynamic Stokes shift measurements reveal very slow components for the IL relaxation. Lighting up with ionic liquids: A novel intrinsic luminescent room‐temperature ionic liquid (RTIL) based on [P6,6,6,14][ANS] (trihexyltetradecylphosphonium 8‐anilinonaphthalene‐1‐sulfonate) has been prepared and characterized by spectroscopic techniques (see figure). Detailed photophysical studies highlight the influence of the RTIL environment on the ANS fluorescence as well as the effect of the viscosity and electrostatic interactions between the ions. ANS can be an interesting means to analyze the effect of different cations on an IL.