Proton-transfer spectroscopy of 3-hydroxychromones. Extreme sensitivity to hydrogen-bonding perturbations

Journal Article · Sat Jan 01 00:00:00 EST 1983 · J. Am. Chem. Soc.; (United States)

DOI:https://doi.org/10.1021/ja00353a047· OSTI ID:5350046

McMorrow, D; Kasha, M

Further studies on the role of the excited-state proton transfer in O-hydroxychromes in the mechanism of photoautomerization have indicated that the presence of stoichiometric and substoichiometric traces of water, or other H-bonding impurities, in supposedly dry hydrocarbon solvents controls and competes with the excited-state proton transfer. The luminescence behavior of various mixtures of 3-hydroxyflavone and water from 293 to 77K is reported. At temperatures greater than 200K, the roles of water solutes are disguised; but at lower temperatures, the properties of the solvated molecules dominate the excitation processes. All spectra reported are for quick-frozen, rigid-glass samples, because all effects were noted to be strongly temperature and cooling-rate dependent. At 293K normal molecule uv absorption is very closely mimincked by the green tautomer fluorescence, while at the other end of the temperature region studies, 77K, a sharpening and a shift of the excitation spectrum to longer wavelengths were noted.

• Research Organization: Florida State Univ., Tallahassee
• DOE Contract Number: AS05-78EV05855
• OSTI ID: 5350046
• Journal Information: J. Am. Chem. Soc.; (United States), Vol. 105
• Country of Publication: United States
• Language: English

Related Subjects

74 ATOMIC AND MOLECULAR PHYSICS
37 INORGANIC
ORGANIC
PHYSICAL AND ANALYTICAL CHEMISTRY
FLAVONES
EXCITED STATES
LUMINESCENCE
HYDROXY COMPOUNDS
PHOTOCHEMISTRY
TEMPERATURE EFFECTS
WATER
CHEMISTRY
ENERGY LEVELS
FLAVENOIDS
HYDROGEN COMPOUNDS
ORGANIC COMPOUNDS
ORGANIC OXYGEN COMPOUNDS
OXYGEN COMPOUNDS
640304* - Atomic
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400500 - Photochemistry