Molecules (Feb 2021)

Switching-On Fluorescence by Copper (II) and Basic Anions: A Case Study with a Pyrene-Functionalized Squaramide

  • Giacomo Picci,
  • Jessica Milia,
  • Maria Carla Aragoni,
  • Massimiliano Arca,
  • Simon J. Coles,
  • Alessandra Garau,
  • Vito Lippolis,
  • Riccardo Montis,
  • James B. Orton,
  • Claudia Caltagirone

DOI
https://doi.org/10.3390/molecules26051301
Journal volume & issue
Vol. 26, no. 5
p. 1301

Abstract

Read online

The new symmetric acyclic N,N’-bis(1-pyrenyl) squaramide (H2L) functionalized with the pyrene moiety as a fluorogenic fragment has been designed and its ability to selectively detect specific anions and metals investigated. H2L selectively binds Cl− both in solution (DMSO 0.5% H2O and MeCN) and in the solid state, and allows to selectively detect Cu2+ in MeCN with the formation of a 2:1 metal-receptor complex, with a green intense emission appreciable by naked eye under the UV lamp. The H2L copper complex preserves its emission properties in the presence of Cl−. The addition of basic anions (OH−, CN−, and F−) up to 10 equivalents caused the deprotonation of the squaramide NHs and a dramatic change of the emission properties of the H2L copper complex.

Keywords