title: Photoinduced Electron Transfer of PAMAM Dendrimer-Zinc(II) Porphyrin Associates at Polarized Liquid|Liquid Interfaces.
abstract: The heterogeneous photoinduced electron-transfer reaction of the ion associates between NH2-terminated polyamidoamine (PAMAM) dendrimers and 5,10,15,20-tetrakis(4-sulfonatophenyl)porphyrinato zinc(II) (ZnTPPS(4-)) was studied at the polarized water|1,2-dichloroethane (DCE) interface. The positive photocurrent arising from the photoreduction of ZnTPPS(4-) by a lipophilic quencher, decamethylferrocene, in the interfacial region was significantly enhanced by the ion association with the PAMAM dendrimers. The photocurrent response of the dendrimer-ZnTPPS(4-) associates was dependent on the pH condition and on the generation of dendrimer. A few cationic additives such as polyallylamine and n-octyltrimethyammonium were also examined as alternatives to the PAMAM dendrimer, but the magnitude of the photocurrent enhancement was rather small. The high photoreactivity of the dendrimer-ZnTPPS(4-) associates was interpreted mainly as a result of the high interfacial concentration of photoreactive porphyrin units associated stably with the dendrimer which was preferably adsorbed at the polarized water|DCE interface. The photochemical data observed in the second and fourth generation PAMAM dendrimer systems demonstrated that the higher generation dendrimer which can incorporate a porphyrin molecule more completely in the interior is less efficient for the photocurrent enhancement at the interface. These results indicated that the photoreactivity of ionic reactant at a polarized liquid|liquid interface can readily be modified via ion association with the charged dendrimer.
authors.affiliation: †Faculty of Chemistry, Institute of Science and Engineering and ‡Division of Material Sciences, Graduate School of Natural Science and Technology, Kanazawa University, Kakuma, Kanazawa 920-1192, Japan.|§Department of Materials Engineering and Molecular Science, Graduate School of Science and Technology and ∥Division of Chemistry and Materials Science, Graduate School of Engineering, Nagasaki University, Bunkyo, Nagasaki 852-8521, Japan.
authors.forename: Hirohisa
authors.initials: H
authors.lastname: Nagatani
authors.affiliation: †Faculty of Chemistry, Institute of Science and Engineering and ‡Division of Material Sciences, Graduate School of Natural Science and Technology, Kanazawa University, Kakuma, Kanazawa 920-1192, Japan.|§Department of Materials Engineering and Molecular Science, Graduate School of Science and Technology and ∥Division of Chemistry and Materials Science, Graduate School of Engineering, Nagasaki University, Bunkyo, Nagasaki 852-8521, Japan.
authors.forename: Hiroki
authors.initials: H
authors.lastname: Sakae
authors.affiliation: †Faculty of Chemistry, Institute of Science and Engineering and ‡Division of Material Sciences, Graduate School of Natural Science and Technology, Kanazawa University, Kakuma, Kanazawa 920-1192, Japan.|§Department of Materials Engineering and Molecular Science, Graduate School of Science and Technology and ∥Division of Chemistry and Materials Science, Graduate School of Engineering, Nagasaki University, Bunkyo, Nagasaki 852-8521, Japan.
authors.forename: Taishi
authors.initials: T
authors.lastname: Torikai
authors.affiliation: †Faculty of Chemistry, Institute of Science and Engineering and ‡Division of Material Sciences, Graduate School of Natural Science and Technology, Kanazawa University, Kakuma, Kanazawa 920-1192, Japan.|§Department of Materials Engineering and Molecular Science, Graduate School of Science and Technology and ∥Division of Chemistry and Materials Science, Graduate School of Engineering, Nagasaki University, Bunkyo, Nagasaki 852-8521, Japan.
authors.forename: Takamasa
authors.initials: T
authors.lastname: Sagara
authors.affiliation: †Faculty of Chemistry, Institute of Science and Engineering and ‡Division of Material Sciences, Graduate School of Natural Science and Technology, Kanazawa University, Kakuma, Kanazawa 920-1192, Japan.|§Department of Materials Engineering and Molecular Science, Graduate School of Science and Technology and ∥Division of Chemistry and Materials Science, Graduate School of Engineering, Nagasaki University, Bunkyo, Nagasaki 852-8521, Japan.
authors.forename: Hisanori
authors.initials: H
authors.lastname: Imura
mesh_terms: D050091:Dendrimers / Q000737:chemistry*; D004579:Electron Transport; D005025:Ethylene Dichlorides / Q000737:chemistry*; D006863:Hydrogen-Ion Concentration; D008665:Metalloporphyrins / Q000737:chemistry*; D055668:Photochemical Processes; D011073:Polyamines / Q000737:chemistry*; D014867:Water / Q000737:chemistry*; D015032:Zinc / Q000737:chemistry*
chemical_list: D050091:Dendrimers; D005025:Ethylene Dichlorides; D008665:Metalloporphyrins; C531249:Poly(amidoamine); D011073:Polyamines; D014867:Water; C024565:ethylene dichloride; D015032:Zinc