Absorption and Fluorescence Emission Attributes of a Fluorescent dye: 2,3,5,6-Tetracyano-p-Hydroquinone

作者：Zahid Muhammad^*; Grampp Guenter; Mansha Asim; Bhatti Ijaz Ahmad; Asim Sadia

来源：Journal of Fluorescence, 2013, 23(4): 829-837.

DOI：10.1007/s10895-013-1197-7

• Photoacids
• Excited state proton transfer
• pK(a)
• pK(a)*
• Proton transfer to the solvent
• Hydroquinone

Four cyano groups have been substituted on the aromatic ring of p-hydroquinone (2,3,5,6-tetracyanohydroquinone) in order to study the enhanced photoacidity of this molecule. The acid-base equilibria have been studied using absorption (for ground state pK(a)) and fluorescence (excited state pK(a)) spectra. Three distinct species (neutral, anionic and dianionic forms) were observed in the ground state and only two species (anionic and dianionic forms) were found in the excited state when studied at different pH/H-o in water. Absorption and emission characteristics were studied in various organic solvents, including protic and aprotic solvents. Deprotonation was also investigated using binary mixtures. It has been revealed that absorption and emission spectra are considerably changed with change in media. Proton transfer to the solvent has been observed in various solvents.

• 出版日期2013-7