Switchable Fluorescent and Solvatochromic Molecular Probes Based on 4‐Amino‐N‐methylphthalimide and a Photochromic Diarylethene

Abstract

New fluorescent photochromic compounds (1-H and 1-Boc) have been synthesized and characterized in different solvents. The fluorescence emission can be switched "on" and "off" with visible light and UV, respectively, by means of the photochromic reaction. The emission wavelength and efficiency strongly depend on the polarity of the solvent. The compounds show a positive solvatochromic effect in the emission maxima, and their fluorescence quantum yield decreases as the solvent's polarity increases (from cyclohexane to dioxane). In solvents more polar than dioxane the emission is too weak and therefore undetectable, and thus 1-H and 1-Boc behave as "normal" photochromic compounds. The pho-

Photochromism of Diarylethene Molecules and Crystals: Memories, Switches, and Actuators

“…345,353 The chromophore having the rhodamine dye showed a large fluorescent quantum yield (Φ f ≈ 0.52) and a large fluorescence modulation ratio (94%) in ethanol solution. The emission wavelength and efficiency of compound 252 strongly depend on solvent polarity.…”

Solvent effect on photochromism of a dithienylperfluorocyclopentene having diethylamino group

“…[17][18][19][20] The solvent effects on the reactivity and the absorption band of photochromic compounds have been reported for spiropyrans, [21][22][23][24] spirooxazines, 25 furylfulgides, 26 and diarylethenes. [27][28][29][30][31] In most cases the dipole moment of the molecules plays an important role of the solvent effects. Diarylethenes having maleic anhydride and maleimide at the ethene part have high reactivity in non-polar solvents and low reactivity in polar solvents.…”

Probes for Nanoscopy: Photoswitchable Fluorophores

“…The two moieties are linked in a close proximity by a flexible or rigid spacer [26][27][28][29][30][31][32]. Although other mechanisms are possible (e.g., electron transfer [33][34][35] and electronic effects [36]), the preferred mechanism by which the photochromic reaction is transferred into a fluorescence modulation is usually F€ orster resonance energy transfer (FRET) [37], with the fluorophore (FL) acting as a donor and the two forms of the photochrome playing the role of a selective energy acceptor. The optimum situation for a good fluorescent switch is that only one of the isomers of the photochromic moiety acts as an efficient acceptor (acceptor isomer, AI), while the other is a poor one (neutral isomer, NI).…”

“…Nevertheless, any readout strategy requires only one bright isomer. Rhodamine spiroamides (RSAs) [17,42,43] and adducts containing a fluorophore and [1,3]oxazines [44] or diheteroarylethenes [36] are examples of this kind of fluorescent switches.…”