novel off-on fluorescent sensing system for Hg2+ ions was prepared through self-assembly, by anionic surfactant micelles, of different combinations of 10-alkylacridinium perchlorates (as fluorophores, with a methyl or an n-octyl chain) and N,N-bis(p-alkyloxybenzyl)-3,6-dioxaoctane-1,8-diamines (as receptors, with a methyl or an n-dodecyl chain) in water solution. The fluorescence quenching observed in the absence of metal ions (“off” state), likely due to a photoinduced electron transfer (PET) mechanism from diamine to acridinium moiety, has demonstrated that a communication between the binding site and the signaling unit actually occurs. The addition of Hg2+ resulted in its incorporation in the micelle with the formation of a receptor-metal complex in competition with the PET process, accordingly the fluorescence emission of acridinium was restored (“on” state). The experimental data suggested that compartmentalization effects in the different micellar microenvironments, due to the different hydrophobic degree of the components, can affect the fluorescence response of the sensor and therefore its sensitivity. These systems showed good sensitivity in Hg2+ sensing and its concentration can be linearly determined according to the fluorescence quenching.

Role of anionic micelles in self-assembling of fluorescent acridinium-based chemosensors for the detection of mercury (II) ions

DEL GIACCO, Tiziana
;
GERMANI, Raimondo;PURGATORIO, FEDERICO;TIECCO, MATTEO
2017

Abstract

novel off-on fluorescent sensing system for Hg2+ ions was prepared through self-assembly, by anionic surfactant micelles, of different combinations of 10-alkylacridinium perchlorates (as fluorophores, with a methyl or an n-octyl chain) and N,N-bis(p-alkyloxybenzyl)-3,6-dioxaoctane-1,8-diamines (as receptors, with a methyl or an n-dodecyl chain) in water solution. The fluorescence quenching observed in the absence of metal ions (“off” state), likely due to a photoinduced electron transfer (PET) mechanism from diamine to acridinium moiety, has demonstrated that a communication between the binding site and the signaling unit actually occurs. The addition of Hg2+ resulted in its incorporation in the micelle with the formation of a receptor-metal complex in competition with the PET process, accordingly the fluorescence emission of acridinium was restored (“on” state). The experimental data suggested that compartmentalization effects in the different micellar microenvironments, due to the different hydrophobic degree of the components, can affect the fluorescence response of the sensor and therefore its sensitivity. These systems showed good sensitivity in Hg2+ sensing and its concentration can be linearly determined according to the fluorescence quenching.
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Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/11391/1411979
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