Chemiluminescent 1,2-Dioxetane Iridium Complexes for Near-Infrared Oxygen Sensing

Angew Chem Int Ed Engl. 2022 Mar 14;61(12):e202115704. doi: 10.1002/anie.202115704. Epub 2022 Jan 27.

Abstract

Chemiluminescent iridium-based sensors which demonstrate oxygen dependent responses have been developed. The molecular probes, named IrCL-1, IrCL-2 and IrCL-3 consist of oxygen-sensitive iridium complexes attached to a spiroadamantane 1,2 dioxetane and operate via energy transfer from the chemiexcited benzoate to the corresponding iridium(III) complex. Complexing the iridium(III) center with π-extended ligands results in emission in the biologically relevant, near-infrared (NIR) region. All probes demonstrate varying oxygen tolerance, with IrCL-1 being the most oxygen sensitive. These probes have been further utilized for in vitro ratiometric imaging of oxygen, as well as for intraperitoneal, intramuscular and intratumoral imaging in live mice. To our knowledge, these are the first iridium-based chemiluminescent probes that have been employed for in vitro ratiometric oxygen sensing, and for in vivo tumor imaging.

Keywords: Chemiluminescence; Energy Transfer; Iridium Oxygen Sensor; Ratiometric; Spiroadamantane 1,2-Dioxetanes.

Publication types

  • Research Support, N.I.H., Extramural
  • Research Support, U.S. Gov't, Non-P.H.S.

MeSH terms

  • Animals
  • Heterocyclic Compounds, 1-Ring
  • Iridium*
  • Mice
  • Molecular Probes
  • Oxygen*

Substances

  • Heterocyclic Compounds, 1-Ring
  • Molecular Probes
  • 1,2-dioxetane
  • Iridium
  • Oxygen