title: Guest-Induced Modulation of the Energy Transfer Process in Porphyrin-Based Artificial Light Harvesting Dendrimers.
abstract: A series of dendritic multiporphyrin arrays (PZnTz-nPFB; n = 2, 4, 8) comprising a triazole-bearing focal zinc porphyrin (PZn) with a different number of freebase porphyrin (PFB) wings has been synthesized, and their photoinduced energy transfer process has been evaluated. UV/vis absorption, emission, and time-resolved fluorescence measurements indicated that efficient excitation energy transfer takes place from the focal PZnto PFBwings in PZnTz-nPFB's. The triazole-bearing PZneffectively formed host-guest complexes with anionic species by means of axial coordination with the aid of multiple C-H hydrogen bonds. By addition of various anionic guests to PZnTz and PZnTz-nPFB's, strong bathochromic shifts of PZnabsorption were observed, indicating the HOMO-LUMO gap (ΔEHOMO-LUMO) of PZndecreased by anion binding. Time-resolved fluorescence measurements revealed that the fluorescence emission predominantly takes place from PZnin PZnTz-nPFB's after the addition of CN-. This change was reversible because a treatment with a silver strip to remove CN-fully recovered the original energy transfer process from the focal PZnto PFBwings.
authors.affiliation: Department of Chemistry, Yonsei University , 50 Yonsei-ro, Seodaemoon-Gu, Seoul 120-749, Korea.
authors.forename: Dajeong
authors.initials: D
authors.lastname: Yim
authors.affiliation: Department of Chemistry, Yonsei University , 50 Yonsei-ro, Seodaemoon-Gu, Seoul 120-749, Korea.
authors.forename: Jooyoung
authors.initials: J
authors.lastname: Sung
authors.affiliation: Department of Chemistry, Yonsei University , 50 Yonsei-ro, Seodaemoon-Gu, Seoul 120-749, Korea.
authors.forename: Serom
authors.initials: S
authors.lastname: Kim
authors.affiliation: Department of Chemistry, Yonsei University , 50 Yonsei-ro, Seodaemoon-Gu, Seoul 120-749, Korea.
authors.forename: Juwon
authors.initials: J
authors.lastname: Oh
authors.affiliation: Department of Chemistry, Yonsei University , 50 Yonsei-ro, Seodaemoon-Gu, Seoul 120-749, Korea.
authors.forename: Hongsik
authors.initials: H
authors.lastname: Yoon
authors.affiliation: Department of Chemistry, Yonsei University , 50 Yonsei-ro, Seodaemoon-Gu, Seoul 120-749, Korea.
authors.forename: Young Mo
authors.initials: YM
authors.lastname: Sung
authors.affiliation: Department of Chemistry, Yonsei University , 50 Yonsei-ro, Seodaemoon-Gu, Seoul 120-749, Korea.
authors.forename: Dongho
authors.identifier: 0000-0001-8668-2644
authors.initials: D
authors.lastname: Kim
authors.affiliation: Department of Chemistry, Yonsei University , 50 Yonsei-ro, Seodaemoon-Gu, Seoul 120-749, Korea.
authors.forename: Woo-Dong
authors.identifier: 0000-0002-1281-6037
authors.initials: WD
authors.lastname: Jang