Switching from intramolecular energy transfer to intramolecular electron transfer by the action of pH and Zn2+ co-ordination

M. Teresa Albelda, Pilar Díaz, Enrique García-España, João C. Lima, Carlos Lodeiro, J. Seixas de Melo, A. Jorge Parola, Fernando Pina, Concepción Soriano

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Intramolecular electron (eT) and energy transfer (ET) have shown to occur in a covalently linked donor-acceptor (CLDA) system consisting of a naphthalene donor covalently linked through a polyamine chain connector to an anthracene acceptor; the connector has been chosen in order to switch ON or OFF the energy flux as a function of its protonation state as well as by co-ordination to Zn2+. The largest energy transfer efficiency (η = 0.61) occurs for the fully protonated form (pH < 2), while at pH > 9 (eT) from the lone pairs of the nitrogens to the excited fluorophore takes place, leading to complete quenching of the emission. On the other hand at neutral and basic pH values, coordination of Zn2+ prevents the eT quenching allowing the ET process to occur.

Original languageEnglish
Pages (from-to)63-68
Number of pages6
JournalChemical Physics Letters
Issue number1-2
Publication statusPublished - 13 Feb 2002



  • Molecules
  • Ligands
  • Stability constants

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