set of new ligands, L2H(2)-L5H(2), containing the 1,4,8,11-tetraaza-5,7-dione framework has been prepared, The ligands feature lipophilic substituents either on the carbon atom in the 6 position or on the amino groups, or on both. The solution behaviour of the ligands when included in TritonX-100 micelles has been investigated by means of potentiometric titrations and protonation and complexation constants for the Cu2+ cation have been determined in micellar medium. Micellar assemblies containing the ligands and pyrene have been prepared, and coupled pH-metric and fluorimetric titrations allowed the determination of the response of the systems as ON-OFF fluorescent sensors for Cu2+. A correlation between the effective lipophilicity of the ligand and the residual fluorescence (i.e. the fluorescence of the OFF state) was observed, and with the more lipophilic ligand, L3H(2), we obtained a residual fluorescence as low as 8%, with a significant improvement with respect to other published systems. On the other hand, introduction of functionalities on the amino groups of 1,4,8,11-tetraaza-5,7-dione brings the drawback of a small but significant decrease of the exploitable fluorescence, i.e. the fluorescence of the system in the absence of added Cu2+, at the pH value suitable for full metal complexation

Residual and exploitable fluorescence in micellar self-assembled ON-OFF sensors for copper(II).

PALLAVICINI, PIERSANDRO;PATRONI, STEFANO;PASOTTI, LUCA
2007-01-01

Abstract

set of new ligands, L2H(2)-L5H(2), containing the 1,4,8,11-tetraaza-5,7-dione framework has been prepared, The ligands feature lipophilic substituents either on the carbon atom in the 6 position or on the amino groups, or on both. The solution behaviour of the ligands when included in TritonX-100 micelles has been investigated by means of potentiometric titrations and protonation and complexation constants for the Cu2+ cation have been determined in micellar medium. Micellar assemblies containing the ligands and pyrene have been prepared, and coupled pH-metric and fluorimetric titrations allowed the determination of the response of the systems as ON-OFF fluorescent sensors for Cu2+. A correlation between the effective lipophilicity of the ligand and the residual fluorescence (i.e. the fluorescence of the OFF state) was observed, and with the more lipophilic ligand, L3H(2), we obtained a residual fluorescence as low as 8%, with a significant improvement with respect to other published systems. On the other hand, introduction of functionalities on the amino groups of 1,4,8,11-tetraaza-5,7-dione brings the drawback of a small but significant decrease of the exploitable fluorescence, i.e. the fluorescence of the system in the absence of added Cu2+, at the pH value suitable for full metal complexation
File in questo prodotto:
Non ci sono file associati a questo prodotto.

I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.

Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/11571/34870
Citazioni
  • ???jsp.display-item.citation.pmc??? ND
  • Scopus 22
  • ???jsp.display-item.citation.isi??? 21
social impact