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

Journal Article · Fri Dec 31 23:00:00 EST 1982 · 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), Journal Name: J. Am. Chem. Soc.; (United States) Vol. 105; ISSN JACSA
• Country of Publication: United States
• Language: English

Related Subjects

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY
400104 -- Spectral Procedures-- (-1987)
400500 -- Photochemistry
640304* -- Atomic
Molecular & Chemical Physics-- Collision Phenomena
74 ATOMIC AND MOLECULAR PHYSICS
CHEMISTRY
ENERGY LEVELS
EXCITED STATES
FLAVENOIDS
FLAVONES
HYDROGEN COMPOUNDS
HYDROXY COMPOUNDS
LUMINESCENCE
ORGANIC COMPOUNDS
ORGANIC OXYGEN COMPOUNDS
OXYGEN COMPOUNDS
PHOTOCHEMISTRY
TEMPERATURE EFFECTS
WATER