Reversible negative photochromic sulfo-substituted spiropyrans

• A detailed preparation and characterization of sulfonyl-containing new spiropyrans.
• The satisfactory negative photochromic properties and fatigue resistance of the compound.
• The study on the influence of substituents on the photochromic properties of spiropyrans.

A series of sulfonyl-containing spiropyrans exhibiting negative photochromism were designed and synthesized. The prepared compounds show more stability for the brightly colored state in the dark-adapted than the colorless state under visible irradiation. Negative photochromic properties and fatigue resistance of these compounds in solution were confirmed by UV spectroscopy with time variation. Single-crystal X-ray diffraction analysis, NMR and variable-time absorption spectra studies suggest that the negative photochromism of the compounds involved a ring-opening spiro CO bond cleavage of the spiropyran followed by an intramolecular proton transfer.

A series of sulfonyl-containing spiropyrans exhibiting negative photochromism were designed and synthesized. The photochromic properties and fatigue resistance of these compounds in solution were investigated in detail by UV spectroscopy with time variation. The influence of substituents on the photochromic properties of these spiropyrans has been studied.Figure optionsDownload as PowerPoint slide