A new application for bis(cyclometalated) iridium(III) species containing ancillary acyclic diaminocarbene ligands, viz. for sensing of mercury(II) ions, is disclosed. A family of bis(cyclometalated) iridium(III) species supported by both parent isocyanide and acyclic diaminocarbene ligands was prepared, and their electrochemical and photophysical properties were evaluated, revealing efficient blue-green phosphorescence in solution with quantum yields of up to 55%. We uncovered that the photophysical properties of these complexes are dramatically altered by the presence of metal ions and that the complex [Ir(ppy)2(CN){C(NH2)(NHC6H4-4-X)}] with an ADC ligand reacts selectively with Hg2+ ions, enabling its use for sensing of mercury(II) ions in solution. The limit of detection was as low as 2.63 × 10-7 M, and additional mechanistic studies indicated the formation of an unusual dinuclear iridium(III) cyclometalated intermediate, bridged by a mercury dicyano fragment as a driving force of mercury sensing.

Original languageEnglish
Pages (from-to)2209-2222
Number of pages14
JournalInorganic Chemistry
Volume59
Issue number4
Early online date3 Feb 2020
DOIs
StatePublished - 17 Feb 2020

    Scopus subject areas

  • Inorganic Chemistry
  • Physical and Theoretical Chemistry

    Research areas

  • CYCLOMETALATED IR(III) COMPLEXES, EXCITED-STATE PROPERTIES, BLUE PHOSPHORESCENCE, HG2+, SENSOR, CHEMODOSIMETER, CARBENE, DESIGN, COORDINATION, PHOTOPHYSICS

ID: 51872008