Color‐Change Photoswitching of an Alkynylpyrene Excimer Dye

Abstract

We describe a photoswitchable DNA-based dimeric dye that visibly changes fluorescence from green to blue upon UV irradiation. A novel bis-alkyne-dependent [2+2+2] cycloaddition is proposed as a mechanism for the color change in air. The photoinduced structural switching results in spatial separation of stacked pyrene units, thereby causing selective loss of the excimer emission. We demonstrate and suggest several applications for this novel photoswitch.

Alkyne–Alkyne Photo-cross-linking on the Flipping-out Field

“…11 Recently, the photoinduced [2 + 2 + 2] cycloaddition reaction of intramolecular alkynylpyrenes and molecular oxygen was reported by Kool's group, and the reaction proceeded without any photocatalysts due to the photoproperty of the alkynylpyrene. 12 Based on this information, we alternately arranged the Ph and/or An bases on the ODN1-ODN3 duplex (Figure 3A). We expected that the Ph and/or An bases flip the complementary base out and create a specific field where the two alkynes overlap each other (Figure 3A).…”

“…According to the report by Liang’s group, the alkyne–alkyne photoreaction is catalyzed by a photocatalyst and provides a 1,4-enedione by reacting with molecular oxygen . Recently, the photoinduced [2 + 2 + 2] cycloaddition reaction of intramolecular alkynylpyrenes and molecular oxygen was reported by Kool’s group, and the reaction proceeded without any photocatalysts due to the photoproperty of the alkynylpyrene . Based on this information, we alternately arranged the Ph and/or An bases on the ODN 1 -ODN 3 duplex (Figure A).…”

Fluorescence modulation via photoinduced spin crossover switched energy transfer from fluorophores to FeII ions

“… 1 , 2 The modulation of fluorescence signals via light is particularly attractive for noninvasive optical read-out technologies owing to the potential applications in optical storage, optical switches and sensors. 3 – 7 Producing a coupling between a fluorophore unit and a light-responsive unit is a rational way to yield photoswitchable fluorescence emission. Previous strategies for achieving phototunable fluorescence emission for the development of new fluorescence switches mainly involved linking organic photochromic groups with fluorescent units via covalent bonds.…”

Of Twists and Curves: Electronics, Photophysics, and Upcoming Applications of Non‐Planar Conjugated Organic Molecules

“…Large Stokes shifts occur when the energy‐minimum geometry in the excited state is significantly different from the geometry of the molecule in the ground state (Figure a). Stokes shifts are strongly dependent on: 1) excited‐state ICT emission 2) excited‐state intramolecular proton‐transfer (ESIPT) and 3) exciplex formation . The conformationally flexible NPCOMs, in which the electron distribution in the excited state is very different from that of the ground state exhibit large Stokes shift and multiple emission maxima .…”