Abstract
Molecules capable of performing highly efficient energy transfer and ultrafast photoinduced electron transfer in well-defined multichromophoric structures are indispensable to the development of artificial photofunctional systems. Herein, we report on the synthesis, characterization, and photophysical properties of a rationally designed multichromophoric tetracationic cyclophane, DAPPBox4+, containing a diazaperopyrenium (DAPP2+) unit and an extended viologen (ExBIPY2+) unit, which are linked together by two p-xylylene bridges. Both1H NMR spectroscopy and single-crystal X-ray diffraction analysis confirm the formation of an asymmetric, rigid, box-like cyclophane, DAPPBox4+. The solid-state superstructure of this cyclophane reveals a herringbone-type packing motif, leading to two types of π···π interactions: (i) between the ExBIPY2+ unit and the DAPP2+ unit (π···π distance of 3.7 Å) in the adjacent parallel cyclophane, as well as (ii) between the ExBIPY2+ 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 DAPPBox4+ at 330 nm, rapid and quantitative intramolecular energy transfer occurs from the1*ExBIPY2+ unit to the DAPP2+ unit in 0.5 ps to yield1*DAPP2+. The same excitation wavelength simultaneously populates a higher excited state of1*DAPP2+ which then undergoes ultrafast intramolecular electron transfer from1*DAPP2+ to ExBIPY2+ to yield the DAPP3+•-ExBIPY+• radical ion pair in τ = 1.5 ps. Selective excitation of DAPP2+ at 505 nm populates a lower excited state where electron transfer is kinetically unfavorable.
Original language | English (US) |
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Pages (from-to) | 4107-4116 |
Number of pages | 10 |
Journal | Journal of the American Chemical Society |
Volume | 139 |
Issue number | 11 |
DOIs | |
State | Published - Mar 22 2017 |
Funding
This research was conducted as part of the Joint Center of Excellence in Integrated Nanosystems at King Abdulaziz City for Science and Technology (KACST) and Northwestern University (NU). The authors thank both KACST and NU for their continued support of this research. This work was also supported by the Chemical Sciences, Geosciences, and Biosciences Division, Office of Basic Energy Sciences, U.S. Department of Energy (DOE) under grant no. DE-FG02- 99ER14999 (M.R.W.). J.T.H. and O.K.F. gratefully acknowledge financial support by the U.S. DOE, Office of Science, Office of Basic Energy Sciences (grant No. DE-FG02 87ER13808) and Northwestern University. H.X. and W.A.G. were supported by NSF (EFRI-00155EI-1332411).
ASJC Scopus subject areas
- Catalysis
- General Chemistry
- Biochemistry
- Colloid and Surface Chemistry
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CCDC 1480961: Experimental Crystal Structure Determination
Gong, X. (Creator), Young, R. M. (Creator), Hartlieb, K. J. (Creator), Miller, C. (Creator), Wu, Y. (Creator), Xiao, H. (Creator), Li, P. (Creator), Hafezi, N. (Creator), Zhou, J. (Creator), Ma, L. (Creator), Cheng, T. (Creator), Goddard, W. A. (Contributor), Farha, O. K. (Creator), Hupp, J. T. (Creator), Wasielewski, M. R. (Creator) & Stoddart, J. F. (Creator), Cambridge Crystallographic Data Centre, 2017
DOI: 10.5517/ccdc.csd.cc1lq1y9, http://www.ccdc.cam.ac.uk/services/structure_request?id=doi:10.5517/ccdc.csd.cc1lq1y9&sid=DataCite
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