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.
ASJC Scopus subject areas
- Colloid and Surface Chemistry
FingerprintDive into the research topics of 'Intramolecular Energy and Electron Transfer within a Diazaperopyrenium-Based Cyclophane'. Together they form a unique fingerprint.
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