The
potential of pyrene-1-sulfonate to act as an emitting anion
for the development of ionic liquids is explored here. Amphiphilic
trimethylpropylammonium hepta(isooctyl)octasilsesquioxane and conventional
imidazolium, namely, 1-vinyl-3-hexyl-, 1-vinyl-3-decyl-, and 1-methyl-3-decyl-imidazolium,
featuring moderate alkyl chain length substituents, have been chosen
as countercations. The new species have been synthesized via simple
metathesis reactions involving pyrene-1-sulfonate sodium salt and
the appropriate halide cation precursors. Their thermal behavior has
been investigated by thermogravimetric and differential scanning calorimetry
at different scanning rates. According to this latter technique, only
the trimethylpropylammonium hepta(isooctyl)octasilsesquioxane pyrenesulfonate
adduct, displaying a reversible glass transition at −4.2 °C,
may be classified as an ionic liquid. All pyrene-1-sulfonate imidazolium-based
ion pairs are crystalline solids with the melting point just above
100 °C that produce very complex, nonreversible, and scanning
rate-dependent thermograms, very likely arising from polymorphism
phenomena. Such a behavior may be attributed to the pyrene-1-sulfonate
polycyclic system, which in solution, as confirmed through spectroscopic
characterization, displays a general attitude in promoting supramolecular
structures via cation interactions. Emission lifetime measurements
on the emitting fluorophore reveal that there are at least two different
active species, whereas light scattering measurements show the presence
of aggregates with hydrodynamic radii depending on the medium and
adduct concentration. Tests aimed at investigating the potential of
these novel pyrene-1-sulfonate salts in functionalization/exfoliation
of graphite flakes are also reported here.