ARAMENDIA Pedro Francisco
congresos y reuniones científicas
Detection of Cu(II) by luminescence quenching of complexes of Eu(III): The development of a Cu(II) sensor
La Plata
Congreso; VIII Encuentro Latinoamericano de FotoquĂ­mica y FotobiologĂ­a; 2004
Lanthanide's luminescent properties make these compounds especially profitable for the design of luminescent labels and sensors. In fact, luminescence of Eu(III) and Tb(III) complexes was reported as pH-dependent (1) or as selective anion binding (2) systems in aqueous solution. The efficient quenching of the luminescence of [Eu(DPA)33-]a by Cu(II) was used to develop a simple device to monitor this metal ion in aqueous solution. In addition, we also synthesized a highly luminescent complex of Eu(III) based on a macrocycle polyaminocarboxylate chelate (dtpa)b covalently bounded to an organic sensitizer 7-amino-4-methyl-coumarin, [Eu(dtpa-coumarine)]. The coumarine sensitizer has the advantage that can be excited at a longer wavelength (l exc= 330 nm) than the DPA in [Eu(DPA)33-] (l exc= 290 nm). These lanthanide complexes were incorporated into a sol-gel matrix using TMOS or TEOS as the silicon alcoxide precursor in ethanol and acidified water. Small square glasses were dip-coated and left drying at room temperature for at least 2 days (TMOS) and 30 days (TEOS). The samples were hydrated in an aqueous solution of ammonia with Cu(II) ions and the quenching of the fluorescence of the complexes was measured by transmission at l em= 615 nm in a front face geometry. Signal reversibility to Cu(II) was observed when the samples were washed with water. () S. M. Blair et al. Inorg Chem, 2001, 40, 5860-5867. (2) M., Montalti, et al. J. Am. Chem. Soc., 2001, 123, 12694-12695. a H2DPA (2,6- pyridinedicarboxylic acid), b dtpa (diethylenetriaminepentaacetic acid)H2DPA (2,6- pyridinedicarboxylic acid), b dtpa (diethylenetriaminepentaacetic acid)