Towards Incorporation in Larger Architectures: A Polymeric Halogen Bond-Based Iridium Sensor

This study reports the synthesis and characterization of a "click-able" iridium(III) complex as halogen bond-based anion sensor. The functionalization is exemplarily demonstrated by the attachment of poly(ethylene glycol) azide via a "copper-click"-reaction. Subsequently, the polymeric XB donor complex is characterized in depth with 1H NMR spectroscopy, size exclusion chromatography, and MALDI-ToF-MS. Moreover, the anion binding capabilities are demonstrated with emission titrations revealing strong anion complexation. These findings emphasize the great potential of this approach to tune the complex's properties or include other functions such as cation complexation sites to exploit cooperative effects by using polymeric substituents on the iridium complex. The study presents the synthesis of a polymer containing a tris-heteroleptic Ir(III) complex as anion sensor. The functionalization with a polymer is exemplarily demonstrated with PEG azide and the polymeric complex is characterized in solution. Moreover, the anion-binding capabilities of the sensor are demonstrated with emission titrations.image