Iridium(III)-Incorporating Self-Healing Polysiloxanes as Materials for Light-Emitting Oxygen Sensors

Polymer-metal complexes (PMCs) based on poly(2,2'-bipyridine-4,4'-dicarboxamide-co-polydimethylsiloxanes) with cyclometalated di(2-phenylpyridinato-C²,N')iridium(III) fragments and cross-linked by Zn²⁺ (Zn[Ir]-BipyPDMSs) or Ir³⁺ (Ir[Ir]-BipyPDMSs) represent flexible, stretchable, phosphorescent, and self-healing molecular oxygen sensors. PMCs provide strong phosphorescence at λ_em = 595-605 nm. Zn[Ir]-BipyPDMS with PDMS chain length of M_n = 5000 has the highest quantum yield of 9.3% and is a molecular oxygen sensor at different O₂ concentrations (0-100 vol%) compared to Ir[Ir]-BipyPDMSs. A Stern-Volmer constant is determined for Zn[Ir]-BipyPDMS as K_SV = 0.014%^-1, which is similar to the reported oxygen-sensitive iridium(III) complexes. All synthesized PMCs exhibit high elongation at break (up to 1100%) and self-healing efficiency (up to 99%).