Photophysics of Iridium(III) (2‐phenylpyridine)(2,2’,6,2”‐terpyridine) Chloride Encapsulated within the Zinc(II) Polyhedral MOF, USF‐2

Abstract

AbstractPhotoactive metal‐organic frameworks (MOFs) provide an important class of functional porous materials for a wide range of applications including light harvesting, photocatalysis and photodynamic therapy. Two strategies have been employed in the development of photoactive MOFs, one in which the photoactive element is incorporated as an element of the framework itself and the other in which the photoactive element serves as a guest within the MOF cavities. Transition metal polyimines have now been non‐covalently incorporated within the cavities of a large number of MOFs with the RuII‐polyimine being the most widely examined guest complex. Previous studies have demonstrated that the nature of the cavity modulates the Ru‐polyimine photophysics. Here, an IrIII(terpyridine)(phenylpyridine)Cl complex has been encapsulated within the Zn‐polyhedral MOF, USF‐2. Unlike the Ru‐polyimines, the excited state photophysics associated with the encapsulated Ir polyimine shows very little change in either the steady state emission and emission lifetime. The slight decrease in emission lifetime is attributed to energy transfer between encapsulated Ir complexes. These results indicate that transition metal polyimines that exhibit excited state structural changes demonstrate the largest perturbations upon confinement.