Abstract
2-Hydroxybiphenyl demonstrates proton transfer in the lowest excited singlet state in 1,4-dioxane-water mixtures. The dissociation reaction of the directly excited neutral molecule is strongly solvent dependent and independent of solution acidity. The reprotonation of the conjugate base, however, depends predominantly on the acidity of the solution and on the bulk dielectric constant of the solvent. A linear relationship between the ratio of the relative fluorescence efficiencies of -hydroxybiphenyl and its conjugate base, and the hydrogen ion concentration is obtained only if proper Brønsted activity factors are included in the relationship. These factors can be calculated from electrostatics and are simple powers of the activity coefficients which would be derived from Debye-Hückel theory and which are necessary to convert the formal hydrogen ion concentration to hydrogen ion activity. Using this approach it is possible to calculate pH from hydrogen ion concentration in dioxane-water solutons, containing mole fractions of up to 0.1 of the organic component.
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
