Substituent-control exciton in J-aggregates of protonated water-insoluble porphyrins.
A series of protonated porphyrin J-aggregates of various water-insoluble tetraphenylporphyrin derivatives was prepared by aggregation at the liquid-liquid or gas-liquid interface. Using atomic force microscopy, we observed microcrystalline porphyrin J-aggregates. The J-aggregates have two strong exciton bands corresponding to the B (Soret)- and Q-bands of the protonated porphyrin. Interestingly, the excitation energy of the lower exciton (denoted by S1) markedly depends on the meso-substituents, whereas that of the higher exciton (denoted by S2) does not depend on them. These results indicate that the nature of the exciton coupling of the S1 transition dipole moment can be systematically changed by the substituents.
Okada
Shinsuke
S
Department of Applied Chemistry, Graduate School of Engineering, and Department of Chemistry, Graduate School of Arts and Sciences, The University of Tokyo, 3-8-1 Komaba, Meguro-ku, Tokyo 153-8902, Japan.
Segawa
Hiroshi
H
D018625:Microscopy, Atomic Force; D011166:Porphyrins / Q000737:chemistry*; D011522:Protons; D012995:Solubility; D013057:Spectrum Analysis; D014867:Water / Q000737:chemistry
D011166:Porphyrins; D011522:Protons; C409084:tetraphenylporphyrin; D014867:Water