Beilstein J. Org. Chem.2025,21, 358–368, doi:10.3762/bjoc.21.26
-n-butylammonium salts (TBAX: F, Cl, Br, I, CN). Exclusively cyanide and fluoride anions lead to a naked-eyeeffect due to a change of the solution’s colour from yellow-orange to pale yellow (Figure 5). At the same time, a new fluorescence band appears at 420–440 nm. The Stokes shifts of fluorescence
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Graphical Abstract
Scheme 1:
Synthesis of 2-hetaryl-substituted 1,3-tropolones 1.
Beilstein J. Org. Chem.2024,20, 552–560, doi:10.3762/bjoc.20.47
were isolated preparatively and fully characterized by IR, 1H, and 13C NMR spectroscopy as well as HRMS and XRD methods. The reverse thermal reaction was catalyzed by protonic acids. N-Acylated compounds exclusively with Fe2+ formed nonfluorescent complexes with a contrast naked-eyeeffect: a color
light and H+ or sequential addition of Fe2+ and AcO− ions.
Keywords: fluorescence; molecular switches; N→O acyl rearrangement; nakedeyeeffect; photochromism; Introduction
Photochromism is defined as the reversible transformation of a molecular entity between different forms, having different
, HRMS and X-ray diffraction analysis. Selectively, Fe2+ caused an appearance of new broad long-wavelength absorption bands at 480−530 nm with a contrast naked-eyeeffect: a visually distinguishable color change of the solutions from yellow to dark orange. The obtained complexes with Fe2+ in acetonitrile
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Graphical Abstract
Scheme 1:
Synthesis of compound 1 and N-acylated compounds 2a–c.