Sensing hazardous metal ions using a fluoroionophore calix[4]arene species containing two 8-oxyquinoline groups

Abstract

The interaction of a calix [4]arene-based species containing two 8-oxyquinoline chromophore pendants with hazardous metal ions has been investigated using optical absorption and fluorimetric techniques. In the presence of Hg 2+ , Cd 2+ , and Pb 2+ ions, there is only a small decrease of the calixarene absorption band at 283 nm. The main changes are associated with the absorption band of the 8-oxyquinoline group at 315 nm, undergoing a systematic bathochromic shift to above 350 nm. In addition, a systematic decrease of the oxyquinoline emission at l em = 392 nm (l exc = 315 nm) has been observed. These observations are consistent with the coordination of the metal ions to the quinoline groups attached to the calixarene ligand, providing a useful fluoroinophore species for analytical purposes.Résumé : Faisant appel aux techniques d'absorption optique et fluorimétrique, on a étudié les réactions d'interaction entre des ions métalliques dangereux et des espèces à base de calix[4]arène contenant deux chromophores pendants 8-oxyquinoléine. En présence des ions Hg 2+ , Cd 2+ et Pb 2+ , on n'observe qu'une faible diminution de la bande l'absorption du calixarène à 283 nm. Les principaux changements sont associés à la bande d'absorption du groupe 8-oxyquinoléine à 315 nm qui subit un déplacement bathochrome systématique au-dessus de 350 nm. De plus, on observe une diminution systématique de l'émission de l'oxyquinoléine à lém = 392 nm (lexc = 315 nm). Ces observations sont en accord avec une coordination des ions métalliques par les groupes quinoléines attachés au ligand calixarène, fournissant une espèce fluoroionophore pour des besoins analytiques.

Cation-induced fluorescent excimer emission in calix[4]arene-chemosensors bearing quinoline as a fluorogenic unit: experimental, molecular modeling and crystallographic studies

“…23 The structure of the quinoline moiety is similar to that of the naphthyl unit, however only a few studies have been reported using quinoline as a fluorogenic unit in calixarene based fluoroionophores. [24][25][26][27] These quinoline containing systems have been reported for sensing of Cu 2+ and Eu 3+ , and also as redox switch as a data storage prototype, however no excimer formation is noted in these systems. [24][25][26] Recently, another calixarene based fluoroionophore with oxyquinoline as a fluorogenic unit has been reported for sensing of toxic metal ions such as Hg 2+ , Cd 2+ and Pb 2+ and weak excimer emission is noted upon addition of metal ions but no detailed discussion on it is reported.…”

“…[24][25][26] Recently, another calixarene based fluoroionophore with oxyquinoline as a fluorogenic unit has been reported for sensing of toxic metal ions such as Hg 2+ , Cd 2+ and Pb 2+ and weak excimer emission is noted upon addition of metal ions but no detailed discussion on it is reported. 27 Quinoline based receptors of non-macrocyclic ligands, however, have been reported, which exhibited intra-and intermolecular excimer emission upon hydrogen bond mediated complexation with organic acids and phosphate anion. [28][29][30] With the aim to develop calixarene based chemosensors with excimer emission, we have synthesised a number of calix [4]arene derivatives with a quinoline moiety as a fluorophore.…”