Charge transfer fluorescence of some N-benzoylindoles

Abstract

. Can. J. Chem. 65, 245 (1987). The fluorescence properties of various N-carbonyl-substituted indoles (compounds 1-7) are examined. The N-benzoyl-indole derivatives 1 and 3-5 are shown to fluoresce weakly and the effect of solvent polarity upon the energy of the emitting state and upon the quantum yield of fluorescence is described. It is concluded that the initially formed singlet excited state is non-emissive and can relax to an intramolecular charge transfer state which is weakly fluorescent. The solvent effects are consistent with a general type of solvent interaction, and the solvent-induced shifts in the wavelength of the fluorescence emission correlate well with the Lippert equation relating the stabilisation of the excited state to a function of solvent dielectric and refractive index. A poor correlation with the empirical ET(30) solvent polarity parameter is observed. [Traduit par la revue]

Solvent Effects on the Fluorescence Properties of Methyldihydroquinolinones

“…It can be seen that the data point corresponding to dioxane is off the line; this has been observed in other systems [8] and may arise because the conformation of the dioxane molecule may be altered when it is solvating a charge transfer excited state. From other solvent polarisability-fluorescence wavelength correlations [8] it has been found that the effective dielectric constant of dioxane is 6 or 7.…”

“…From other solvent polarisability-fluorescence wavelength correlations [8] it has been found that the effective dielectric constant of dioxane is 6 or 7. Using a value of this order brings the dioxane point onto the line in Figure 2.…”

Isoindoloindolones - biological activities and syntheses

“…8,9 Isoindoloindolone 1 also exhibit charge-transfer fluorescence with high quantum yields in non polar solvents. 10 …”

Molecular characterization of drug´s nanocarriers based on plasmon-enhanced spectroscopy: Fluorescence (SEF) and Raman (SERS)

“…Los espectros de fluorescencia (λexc=325 nm) de IM y KT en disolución acuosa (datos no mostrados aquí) presentan una emisión muy débil, con máximos a 560 y 522 nm, respectivamente. La presencia de bandas a mayores longitudes de onda con un gran desplazamiento Stokes cuya posición varia con la polaridad del disolvente se debe a la existencia de un complejo de transferencia de carga también detectado en otros Nbenzoilindoles [34]. Cuando la IM está en presencia de AgNPs, su señal de fluorescencia se intensifica (efecto SEF) únicamente a pHs<4.…”