3 years ago

Pyridine–Spiropyran Derivative as a Persistent, Reversible Photoacid in Water

Pyridine–Spiropyran Derivative as a Persistent, Reversible Photoacid in Water
Thomas Halbritter, Josef Wachtveitl, Christoph Kaiser, Alexander Heckel
A highly versatile water-soluble pyridine–spiropyran photoswitch is reported which functions as photoacid in a wide pH range. Under neutral conditions, the open-ring merocyanine (MC) exists to 48% and closes quantitatively by irradiation with visible light, while the reverse reaction occurs rapidly in the dark or by irradiation at 340 nm. The different pKa of the pyridine nitrogen in the closed spiropyran (4.8) and open merocyanine form (6.8) leads to a reversible proton release in a pH range of 3–7. Only negligible hydrolytic decomposition was observed in the pH range from 1 to 12. The application of potentially harmful UV light can be circumvented due to the fast thermal ring-opening except for pH values below 3. Its photoacidic properties make this compound an effective pH-regulating photoswitch in water and enable controlled proton-transfer processes for diverse applications. Additionally, all of the involved protonated states of the compound exhibit discriminative fluorescence features within certain pH ranges, which even expands its utility to a light-controllable, pH-sensitive fluorophore.

Publisher URL: http://dx.doi.org/10.1021/acs.joc.7b01268

DOI: 10.1021/acs.joc.7b01268

You might also like
Discover & Discuss Important Research

Keeping up-to-date with research can feel impossible, with papers being published faster than you'll ever be able to read them. That's where Researcher comes in: we're simplifying discovery and making important discussions happen. With over 19,000 sources, including peer-reviewed journals, preprints, blogs, universities, podcasts and Live events across 10 research areas, you'll never miss what's important to you. It's like social media, but better. Oh, and we should mention - it's free.

  • Download from Google Play
  • Download from App Store
  • Download from AppInChina

Researcher displays publicly available abstracts and doesn’t host any full article content. If the content is open access, we will direct clicks from the abstracts to the publisher website and display the PDF copy on our platform. Clicks to view the full text will be directed to the publisher website, where only users with subscriptions or access through their institution are able to view the full article.