title: Interfacial adsorption state of protonated lipophilic porphyrins in a liquid-liquid system by using reflection spectrometry.
abstract: Analysis by reflection spectrometry was performed to clarify the interfacial adsorption of protonated lipophilic tetraphenylporphyrin derivatives in a dodecane-aqueous sulfuric acid system, and to confirm the utility of partial reflection spectroscopy. Interfacial adsorption was not observed for porphyrins substituted at the 2,6 positions of meso-phenyl groups, suggesting that the substituents prevent porphyrins from forming aggregates by steric hindrance. Polymorphous J-aggregates of acid dications were produced by tetra-p-tolylporphyrin with a saturated interfacial molecular density of 1.0 x 10(-10) mol cm(-2), which could yield 48 degrees as a mean tilting angle of the pyrrole ring plane from the interface normal. Partial-reflection spectrometry can provide sensitive detection and molecular orientation analysis of interfacial adsorbates.
authors.affiliation: Faculty of Engineering and Resource Science, Akita University, 1-1 Tegata Gakuen-cho, Akita 010-8502, Japan. ymoriya@ipc.akita-u.ac.jp
authors.forename: Yoshio
authors.initials: Y
authors.lastname: Moriya
authors.forename: Shinichi
authors.initials: S
authors.lastname: Nakata
authors.forename: Hirotaka
authors.initials: H
authors.lastname: Morimoto
authors.forename: Nobuaki
authors.initials: N
authors.lastname: Ogawa