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STUDIES ON FLAVINS IN ORGANIC SOLVENTS‐I *. SPECTRAL CHARACTERISTICS OF RIBOFLAVIN, RIBOFLAVIN TETRABUTYRATE AND LUMICHROME
Author(s) -
Koziol Jacek
Publication year - 1966
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.1751-1097.1966.tb05759.x
Subject(s) - chemistry , flavin group , riboflavin , cyclohexane , photochemistry , fluorescence , absorption (acoustics) , solvent , absorption spectroscopy , polarity (international relations) , analytical chemistry (journal) , organic chemistry , materials science , quantum mechanics , composite material , enzyme , biochemistry , physics , cell
— The absorption and fluorescence spectra of riboflavin, riboflavin tetrabutyrate and lumichrome have been studied in organic solvents of different polarity including ethanol, acetone, dioxane, pyridine, acetic acid and in cyclohexane‐dioxane mixtures. The molar extinction coefficients of the compounds were measured and the character of solvent sensitive changes observed in the absorption spectra are discussed. The effect of hydrogen bonding and/or intramolecular charge transfer complex are proposed as possible explanation. Changes in the shape of fluorescence emission spectra are less evident; in the case of riboflavin tetrabutyrate, mirror symmetry to the shape of the longest wavelength maximum was observed in low‐polar solvents. Quantum yields of fluorescence are higher the lower the polarity of the solvent used; the value for riboflavin tetrabutyrate is greater than for riboflavin. Changes were also observed in the fluorescence emission spectra of lumichrome in solvents of different polarity. Fairly good agreement was demonstrated for positions of the observed absorption maxima of riboflavin in 98% dioxane, riboflavin tetrabutyrate and lumichrome in 80% cyclohexane in mixture with dioxane and the values calculated from energies of molecular orbitals of flavins computed by B. Pullman and A. Pullman.