Three-component systems for conventional and window-shaped response fluorescent pH indicators.
Three-component systems made of a tetradentate bis-amino bis-quinoline ligand, a transition metal cation (Ni2+ or Cu2+) and a fluorescent indicator (Coumarin 343) have been studied in a water-dioxane (1 : 4 v/v) mixture, through potentiometric, pH-spectrophotometric and pH-fluorimetric titrations. For the Cu2+ containing systems, an "on-off-on" variation of fluorescence intensity vs. pH has been observed, whereas in the presence of Ni2+ a simple "on-off" profile of the fluorescence intensity vs. pH was obtained. These ternary systems thus behave as window-shaped or conventional pH-indicators, depending whether Cu2+ or Ni2+ is used as the cation.
Amendola
Valeria
V
Dipartimento di Chimica Generale, Universita di Pavia, via Taramelli, 12, 27100, Pavia, Italy.
Mangano
Carlo
C
Pallavicini
Piersandro
P