Hydrogen bonding properties of DMSO in ground-state formation and optical spectra of 3-hydroxyflavone anion

• Published in: Chemical physics letters Vol. 467; no. 1; pp. 88 - 93
• Main Authors: Protti, Stefano, Mezzetti, Alberto, Cornard, Jean-Paul, Lapouge, Christine, Fagnoni, Maurizio
• Format: Journal Article
• Language: English
• Published: Elsevier B.V 15-12-2008; Elsevier
• Subjects: Biological Physics; Chemical Physics; Chemical Sciences; Other; Physics
• ISSN: 0009-2614; 1873-4448
• DOI: 10.1016/j.cplett.2008.11.005

3-Hydroxyflavone anion formation in DMSO: hydrogen bonds play a key role in the mechanism and in modulating the spectral properties.
We report ground-state formation of 3-hydroxyflavone (3HF) anion in DMSO. According to the literature this process is possible only in hydrogen bonding donor (HBD) solvents. Our results show that a solvent with zero HBD acidity but sufficiently high hydrogen bonding acceptor basicity can also give anion formation. A possible new mechanism is proposed. Furthermore, theoretical calculations show evidence for the formation of a 3HF
−···DMSOH
+ complex. As 3HF anion is a promising biophysical fluorescent probe, our results can help to understand the factors governing its ground-state formation and how its spectral properties are related to its microenvironment in biological systems.