title: NMR investigations of the interaction between the azo-dye sunset yellow and fluorophenol.
abstract: The interaction of small molecules with larger noncovalent assemblies is important across a wide range of disciplines. Here, we apply two complementary NMR spectroscopic methods to investigate the interaction of various fluorophenol isomers with sunset yellow. This latter molecule is known to form noncovalent aggregates in isotropic solution, and form liquid crystals at high concentrations. We utilize the unique fluorine-19 nucleus of the fluorophenol as a reporter of the interactions via changes in both the observed chemical shift and diffusion coefficients. The data are interpreted in terms of the indefinite self-association model and simple modifications for the incorporation of a second species into an assembly. A change in association mode is tentatively assigned whereby the fluorophenol binds end-on with the sunset yellow aggregates at low concentration and inserts into the stacks at higher concentrations.
authors.affiliation: School of Life Sciences, University of Sussex , Falmer, Brighton, BN1 9QJ, United Kingdom.
authors.forename: Jonathan R
authors.initials: JR
authors.lastname: Katz
authors.forename: Lucy J
authors.initials: LJ
authors.lastname: Day
authors.forename: Iain J
authors.initials: IJ
authors.lastname: Day
mesh_terms: D000465:Algorithms; D001391:Azo Compounds / Q000737:chemistry*; D004396:Coloring Agents / Q000737:chemistry*; D004058:Diffusion; D009682:Magnetic Resonance Spectroscopy; D008956:Models, Chemical; D010636:Phenols / Q000737:chemistry*; D012996:Solutions
chemical_list: D001391:Azo Compounds; D004396:Coloring Agents; D010636:Phenols; D012996:Solutions; C005842:6-hydroxy-5-((p- sulfophenyl)azo)-2-naphthalenesulfonic acid disodium salt; C085046:3-fluorophenol