Intramolecular Energy and Electron Transfer within a Diazaperopyrenium-Based Cyclophane
| Autor: | Xirui Gong, Hai Xiao, William A. Goddard, Ryan M. Young, Yilei Wu, J. Fraser Stoddart, Tao Cheng, Jiawang Zhou, Karel J. Hartlieb, Claire E. Miller, Michael R. Wasielewski, Omar K. Farha, Nema Hafezi, Peng Li, Lin Ma, Joseph T. Hupp |
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| Rok vydání: | 2017 |
| Předmět: |
010405 organic chemistry
Chemistry Viologen General Chemistry 010402 general chemistry Ring (chemistry) Photochemistry 01 natural sciences Biochemistry Catalysis Photoinduced electron transfer 0104 chemical sciences chemistry.chemical_compound Electron transfer Colloid and Surface Chemistry Phenylene Intramolecular force medicine Molecule medicine.drug Cyclophane |
| Zdroj: | Journal of the American Chemical Society. 139:4107-4116 |
| ISSN: | 1520-5126 0002-7863 |
| Popis: | Molecules capable of performing highly efficient energy transfer and ultrafast photo-induced electron transfer in well-defined multichromophoric structures are indispensable to the development of artificial photosynthetic systems. Herein, we report on the synthesis, characterization and photophysical properties of a rationally designed multichromophoric tetracationic cyclophane, DAPPBox^(4+), containing a diazaperopyrenium (DAPP^(2+)) unit and an extended viologen (ExBIPY^(2+)) unit, which are linked together by two p-xylylene bridges. Both ^1H NMR spectroscopy and single crystal X-ray diffraction analysis confirm the formation of an asymmetric, rigid, box-like cyclophane, DAPPBox^(4+). The solid-state superstructure of this cyclophane reveals a herringbone-type packing motif, leading to two types of π···π interactions: (i) between the ExBIPY^(2+) unit and the DAPP^(2+) unit (π···π distance of 3.7 Å) in the adjacent parallel cyclophane, as well as (ii) between the ExBIPY^(2+) unit (π···π distance of 3.2 Å) and phenylene ring in the closest orthogonal cyclophane. Moreover, the solution-phase photophysical properties of this cyclophane have been investigated by both steady-state and time-resolved absorption and emission spectroscopies. Upon photoexcitation of DAPPBox^(4+) at 330 nm, rapid and quantitative intramolecular energy transfer occurs from the ^1*ExBIPY^(2+) unit to the DAPP^(2+) unit in 0.5 ps to yield ^1*DAPP^(2+). The same excitation wavelength simultaneously populates a higher excited state of ^1*DAPP^(2+) which then undergoes ultrafast intramolecular electron transfer from ^1*DAPP^(2+) to ExBIPY^(2+) to yield the DAPP^(3+•) – ExBIPY^(+•) radical ion pair in τ = 1.5 ps. Selective excitation of DAPP^(2+) at 505 nm populates a lower excited state where electron transfer is kinetically unfavorable. |
| Databáze: | OpenAIRE |
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