Coordination properties of a polyamine cryptand with two different binding moieties. A case of a pH-modulated antenna device based on a new Eu(III) cryptate complex

Caria Bazzicalupi, Fernando Pina, Andrea Bencini, Emanuela Berni, Antonio Bianchi, Claudia Giorgi, Vieri Fusi, Barbara Valtancoli, Carlos Lodeiro, Ana Roque

Research output: Contribution to journalArticlepeer-review

18 Citations (Scopus)

Abstract

Protonation and alkali- and alkaline-earth-metal coordination by the dipyridine-containing cryptand L have been studied by means of potentiometric and spectroscopic (UV-vis, 1H NMR) measurements in aqueous solutions. This ligand is constituted by an aliphatic polyamine chain and a coordinating cleft, delimited by two dipyridine units, where the metal ion is lodged. The resulting complexes are characterized by an unusually high stability. The polyamine chain is not involved, or weakly involved, in metal coordination, and facile protonation can occur on the nitrogen atoms of this moiety. Similar coordination features are found in the Eu(III) complex. A fluorescence emission study reveals that the Eu(III) cryptate shows the characteristic visible emission of the metal, due to the intramolecular energy transfer to the metal ion mainly from the lower energy triplet state of the cryptand. On the other hand, the emission intensity is modulated by pH, giving a maximum at neutral pH and decreasing at both acidic and alkaline pH values.

Original languageEnglish
Pages (from-to)6172-6179
Number of pages8
JournalInorganic Chemistry
Volume40
Issue number24
DOIs
Publication statusPublished - 19 Nov 2001

Fingerprint Dive into the research topics of 'Coordination properties of a polyamine cryptand with two different binding moieties. A case of a pH-modulated antenna device based on a new Eu(III) cryptate complex'. Together they form a unique fingerprint.

Cite this