QUENCHING OF BIACETYL FLUORESCENCE AND PHOSPHORESCENCE

The quenching of biacetyl fluorescence and phosphorescence by alcohols, tri-n-butylstannane, aryl- and alkylamines, phenols, and aryl alkyl ethers has been studied in benzene and other solvents. Irreversible hydrogen abstraction appears to be the mechanism for quenching of biacetyl phosphorescence by alcohols and stannane, neither of which measurably quenches biacetyl fluorescence. Phenols quench both biacetyl fluorescence and phosphorescence but aryl alkyl ethers quench only biacetyl phosphorescence (at a rate 103 times slower than analogous phosphorescence quenching by phenols). Aryl- and alkylamines quench both biacetyl fluorescence and phosphorescence. The rates of phenol quenching are slower in solvents which are polar or hydrogen bonding, while the rates of quenching by amines are enhanced by increasing solvent polarity. Pyrene and acridine quench biacetyl phosphorescence (but not biacetyl fluorescence) by physical energy transfer. Mechanisms consistent with these results are discussed. © 1969, American Chemical Society. All rights reserved.