Direct observation of reversible electronic energy transfer involving an iridium center

Research output: Contribution to journalArticlepeer-review


  • Sergey A Denisov
  • Yanouk Cudré
  • Peter Verwilst
  • Gediminas Jonusauskas
  • Marta Marín-Suárez
  • Jorge Fernando Fernández-Sánchez
  • Nathan D McClenaghan

Colleges, School and Institutes

External organisations

  • Université Bordeaux/CNRS, ISM , 351 cours de la Libération, 33405 Talence Cedex, France.


A cyclometalated iridium complex is reported where the core complex comprises naphthylpyridine as the main ligand and the ancillary 2,2'-bipyridine ligand is attached to a pyrene unit by a short alkyl bridge. To obtain the complex with satisfactory purity, it was necessary to modify the standard synthesis (direct reaction of the ancillary ligand with the chloro-bridged iridium dimer) to a method harnessing an intermediate tetramethylheptanolate-based complex, which was subjected to acid-promoted removal of the ancillary ligand and subsequent complexation. The photophysical behavior of the bichromophoric complex and a model complex without the pendant pyrene were studied using steady-state and time-resolved spectroscopies. Reversible electronic energy transfer (REET) is demonstrated, uniquely with an emissive cyclometalated iridium center and an adjacent organic chromophore. After excited-state equilibration is established (5 ns) as a result of REET, extremely long luminescence lifetimes of up to 225 μs result, compared to 8.3 μs for the model complex, without diminishing the emission quantum yield. As a result, remarkably high oxygen sensitivity is observed in both solution and polymeric matrices.


Original languageEnglish
Pages (from-to)2677-2682
Number of pages6
JournalInorganic Chemistry
Issue number5
Early online date20 Feb 2014
Publication statusPublished - 3 Mar 2014