The discolouration rate of a fluorescent dye can act as a visual marker for changes in hydrogen bonding environment, new research shows.
Colourless spiropyrans undergo ring opening to form brightly coloured merocyanines on exposure to UV light. Merocyanines are thermally unstable and relax back to the colourless spiropyrans over time. The merocyanines designed by Simone Ciampi, from the University of Wollongong, Australia, and his colleagues contain a catechol group that can form intramolecular hydrogen bonds, which stabilises the open form and slows down discolouration. However, polar solvents can out-compete intramolecular hydrogen bond formation, and speed up discolouration. In this way, Ciampi’s team were able to visualise the hydrogen bonding character of solvents by adding their dye and observing the rate at which it discoloured.
Read the full article in Chemistry World»
Read the original journal article in ChemComm:
Decoloration rates of a photomerocyanine dye as a visual probe into hydrogen bonding interactions
Simone Ciampi, Paul K. Eggers, Naomi L. Haworth, Nadim Darwish, Pawel Wagner, Michelle L. Coote, Gordon G. Wallace and Colin L. Raston
Chem. Commun., 2015, Advance Article
DOI: 10.1039/C4CC09857A, Communication