title: Intramolecular axial ligation of zinc porphyrin cores with triazole links within dendrimers.
abstract: Stable ligation: A series of dendritic porphyrins, such as that depicted in which benzyl ether dendrons were linked to a porphyrin core through 1,2,3-triazole links, was synthesized. Absorption and fluorescence spectra showed a stable axial ligation at the zinc center of the porphyrin core by triazole links in dendritic wedges and indicated that the position of the triazole links strongly affected the stability of the axial ligation within the dendrimer.A series of dendritic porphyrins 7-9 and 12, in which benzyl ether dendrons were linked to a porphyrin core through 1,2,3-triazole links, were synthesized by Cu(I)-catalyzed cycloaddition of azides and alkynes. Absorption and fluorescence spectra showed a stable axial ligation at the zinc center of the porphyrin core by triazole links in dendritic wedges and indicated that the position of the triazole links strongly affected the stability of the axial ligation within the dendrimer. When the porphyrin core was surrounded by aryl ether dendrons having anionic termini and triazole linkers, a significant rate enhancement for photoinduced electron transfer was observed compared with a similar water-soluble dendritic zinc porphyrin lacking triazole linkers. These triazole links constituted a direct pathway within the dendrimer architecture for electron transfer between the zinc porphyrin core and peripheral electron acceptors.
authors.affiliation: Department of Functional Polymer Science, Faculty of Textile Science and Technology, Shinshu University, Ueda 386-8567, Japan. mkimura@shinshu-u.ac.jp
authors.forename: Mutsumi
authors.initials: M
authors.lastname: Kimura
authors.forename: Yasuhiro
authors.initials: Y
authors.lastname: Nakano
authors.forename: Naoya
authors.initials: N
authors.lastname: Adachi
authors.forename: Yoko
authors.initials: Y
authors.lastname: Tatewaki
authors.forename: Hirofusa
authors.initials: H
authors.lastname: Shirai
authors.forename: Nagao
authors.initials: N
authors.lastname: Kobayashi
mesh_terms: D050091:Dendrimers / Q000138:chemical synthesis* / Q000737:chemistry*; D008665:Metalloporphyrins / Q000138:chemical synthesis* / Q000737:chemistry*; D008958:Models, Molecular; D015394:Molecular Structure; D014230:Triazoles / Q000138:chemical synthesis / Q000737:chemistry*; D015032:Zinc / Q000737:chemistry*
chemical_list: D050091:Dendrimers; D008665:Metalloporphyrins; D014230:Triazoles; C017802:zinc hematoporphyrin; D015032:Zinc