Investigation of J-Aggregates of 2,3,7,8,12,13,17,18-Octabromo-5,10,15,20-tetrakis(4-sulfonatophenyl) Porphyrin in Aqueous Solutions.
Balkis Abdelaziz, Mariachiara Sarà, Sahbi Ayachi, Roberto Zagami, Salvatore Patanè, Andrea Romeo, Maria Angela Castriciano, Luigi Monsù Scolaro
The highly distorted water-soluble 2,3,7,8,12,13,17,18-octabromo-5,10,15,20-tetrakis(4-sulfonatophenyl)porphyrin (Br8 TPPS4 4- ) is readily protonated under acidic pH, forming the diacid H2 Br8 TPPS4 2- and subsequently the zwitterionic H4 Br8 TPPS4 , which eventually evolves into J-aggregates. These latter species exhibit a relevant bathochromic shift with respect to the monomer with a quite sharp band due to motional narrowing. The depolarization ratio measured in resonant light scattering spectra allows estimating a tilt angle of ~20° of the porphyrins in the J-aggregate...
October 26, 2023: Nanomaterials