Marigold flower-like assemblies of phosphorescent iridium-silver coordination polymers

Abstract

Racemic and enantiopure phosphorescent iridium(III)-silver(I) coordination polymers are reported. The polymers rac-, Δ- and ΔΔΔΔ- IrAg were formed, respectively, by the assembly of the chiral iridium metalloligands rac-, Δ- and Δ-[Ir(mesppy)2(qpy)]PF6 (rac-, Δ- and Δ- Ir ) where mesppy is 2-phenyl-4-mesitylpyridinato and qpy is 4,4':2',2'':4'',4'''- quaterpyridine, and Ag+ ions through Npy-Ag linear coordination. The polymers have been characterized in MeNO2 solution by 1H and 1H DOSY NMR and CD spectroscopies and in the solid-state by Scanning Electron Microscopy (SEM); the crystal structures of the racemic polymer rac- IrAg has been obtained by X-ray diffraction. The polymers rac-, Δ- and Δ- IrAg exhibited orange/red emission in solution, in films and as crystals, with intensities comparable to those of the corresponding iridium metalloligands rac-, Δ- and Δ- Ir . The morphology of the enantiopure polymers in the solid-state resemble marigold flower-like nano-porous assemblies while the racemic polymer possesses an irregular morphology formation.