title: Cl- complexation induced H- and J-aggregation of meso-tetrakis(4-sulfonatothienyl)porphyrin diacid in aqueous solution.
abstract: Various porphyrin diacids are known to show controlled self-assembly by inorganic anions. Following the unexpected finding that meso-tetrakis(4-sulfonatothienyl)porphyrin diacid shows Cl(-) specific aggregation in spite of having the anionic substituents, the aggregation behavior of the diacid in aqueous solution with Cl(-) was investigated in detail. We found that Cl(-) induces the H-aggregate, followed by the transformation into the J-aggregate with increasing Cl(-) concentration. For the J-aggregate formation, negatively charged sulfonic acid groups were suggested to be of minor influence. The J-aggregate forms nanoscale macrostructures composed of highly oriented molecules on substrate. To our knowledge, this is the first report of both H- and J-type aggregate formation of a porphyrin diacid in the presence of an aqueous inorganic anion. These results would open the gate for controlling the chromophore packing structure of a porphyrin diacid complexed with an inorganic anion by varying the composition.
authors.affiliation: Research Center for Advanced Science and Technology, The University of Tokyo, 4-6-1, Komaba, Meguro-ku, Tokyo, Japan. arai@dsc.rcast.u-tokyo.ac.jp
authors.forename: Yonbon
authors.initials: Y
authors.lastname: Arai
authors.forename: Hiroshi
authors.initials: H
authors.lastname: Segawa