Nitroanilines as Quenchers of Pyrene Fluorescence

CARLOS AGUDELO-MORALES; OSCAR FERNANDO SILVA; RAQUEL E. GALIAN; JULIA PÉREZ-PRIETO

WILEY-V C H VERLAG GMBH

Lugar: Weinheim; Año: 2012 vol. 13 p. 4195 - 4195

he quenching of pyrene and 1-methylpyrene fluorescence bynitroanilines (NAs), such as 2-, 3-, and 4-nitroaniline (2-NA, 3-NA, and 4-NA, respectively), 4-methyl-3-nitroaniline (4-M-3-NA),2-methyl-4-nitroaniline (2-M-4-NA), and 4-methyl-3,5-dinitroaniline(4-M-3,5-DNA), are studied in toluene and 1,4-dioxane.Steady-state fluorescence data show the higher efficiency ofthe 4-NAs as quenchers and fit with a sphere-of-action model.This suggests a 4-NA tendency of being in close proximity tothe fluorophore, which could be connected with their high polarity/hyperpolarizability. In addition, emission and excitationspectra evidence the formation of emissive pyrene?NAground-state complexes in the case of the 4-NAs and, ina minor degree, in the 2-NA. Moreover, time-resolved fluorescenceexperiments show that increasing amounts of NA decreasethe pyrene fluorescence lifetime to a degree that dependson the NA nat