Intramolecular Energy and Electron Transfer within a Diazaperopyrenium-Based Cyclophane

• DOI: 10.1021/jacs.6b13223
• Publication Date: 2017-02-22T18:16:36Z
• Authors: Xirui Gong; Ryan M. Young; Karel J. Hartlieb; Claire Miller; Yilei Wu; Hai Xiao; Peng Li; Nema Hafezi; Jiawang Zhou; Lin Ma; Tao Cheng; William A. Goddard; Omar K. Farha; Joseph T. Hupp; Michael R. Wasiel...; J. Fraser Stoddart
• Keywords: Cyclophane

Molecules capable of performing highly efficient energy transfer and ultrafast photoinduced electron in well-defined multichromophoric structures are indispensable to the development artificial photofunctional systems. Herein, we report on synthesis, characterization, photophysical properties a rationally designed tetracationic cyclophane, DAPPBox4+, containing diazaperopyrenium (DAPP2+) unit an extended viologen (ExBIPY2+) unit, which linked together by two p-xylylene bridges. Both 1H NMR spectroscopy single-crystal X-ray diffraction analysis confirm formation asymmetric, rigid, box-like DAPPBox4+. The solid-state superstructure this cyclophane reveals herringbone-type packing motif, leading types π···π interactions: (i) between ExBIPY2+ DAPP2+ (π···π distance 3.7 Å) adjacent parallel as well (ii) 3.2 phenylene ring closest orthogonal cyclophane. Moreover, solution-phase have been investigated both steady-state time-resolved absorption emission spectroscopies. Upon photoexcitation DAPPBox4+ at 330 nm, rapid quantitative intramolecular occurs from 1*ExBIPY2+ 0.5 ps yield 1*DAPP2+. same excitation wavelength simultaneously populates higher excited state 1*DAPP2+ then undergoes DAPP3+•–ExBIPY+• radical ion pair τ = 1.5 ps. Selective 505 nm lower where is kinetically unfavorable.