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ON THE MECHANISM OF FLUORESCENCE QUENCHING IN PYRENE‐ AND 3,4‐BENZOPYRENE‐1,3,7,9‐TETRAMETHYLURIC ACID SYSTEMS
Author(s) -
MATSUYAMA A.,
NAGATA C.
Publication year - 1972
Publication title -
photochemistry and photobiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.818
H-Index - 131
eISSN - 1751-1097
pISSN - 0031-8655
DOI - 10.1111/j.1751-1097.1972.tb07336.x
Subject(s) - chemistry , fluorescence , pyrene , photochemistry , quenching (fluorescence) , aqueous solution , excited state , van der waals force , molecule , organic chemistry , physics , quantum mechanics , nuclear physics
T he interaction between aromatic hydrocarbons and purine or its analogues has been widely noted in connection with the possibility of complex formation between carcinogens and DNA or its precursors. Weil‐Malherbe[1], Boyland and Green[2] reported that 1,3,7,9‐tetramethyluric acid (TMUA) solubilizes aromatic hydrocarbons in aqueous solution and exerts a strong quenching action on fluorescence of the hydrocarbons. The solubilization has been attributed to formation of a molecular complex [2]. Complex formation is now thought to be mainly due to van der Waal's force (polarization and dispersion force) rather than charge transfer ( CT ) one[2,3–5]. Van Duuren [3,5] examined fluorescence spectra of TMUA‐hydrocarbon complexes both in solution and in potassium bromide pellets. In solution, the fluorescence spectrum of the complex showed no change in the position of the maximum and in intensity, when compared with that of the free hydrocarbon. In the solid state, however, a blue shift was observed for the fluorescence of the complex. From these results, it was concluded that the complex is entirely dissociated in solution and the fluorescence shift observed in the solid state is the result of the interaction in the excited state. The present note describes a new observation which is useful for understanding the mechanism of fluorescence quenching in the hydrocarbons‐TMUA systems.