Synthesis, characterization and aggregation behavior of room temperature ionic liquid based on porphyrin- trihexyl(tetradecyl)phosphonium adduct

A room temperature ionic liquid (RT-IL) made by the negatively charged water soluble meso-tetrakis(4 sulfonatophenyl)porphyrin (TPPS4) and the positively charged trihexyl(tetradecyl)phosphonium (CYPHOS® IL 101) has been synthesized and fully characterized by NMR, MALDI-TOF, differential scanning calorimetry and thermogravimetric analyses. Moreover, the growth of nanosized porphyrin J-aggregates has been induced in solution through the “in situ” photogeneration of HCl acid in chlorinated solvent as well as the addition in solution of a strong chiral acid. In this latter case supramolecular chiral induction has been observed on the resulting emissive nanosized aggregates. The data reported clearly evidence the central role of trihexyl(tetradecyl)phosphonium(THTDP) counter-cation in i) determining themonomeric nature of the adduct in chlorinate solution, and ii) in limiting the size of the aggregates on a nanometric scale.