Layered materials provide a two-dimensional interlayer space suitable for accommodating molecules with a designed functionality. In this study, inorganic−organic hybrids were prepared by intercalation of anionic porphyrin sensitizers into the host structure of layered zinc hydroxide salts. The inorganic host offers stabilization and protection, whereas the guest species provide the photofunction. The properties and arrangement of porphyrin molecules in the interlayer space were studied by a combination of experimental techniques and molecular simulations. Intercalation of porphyrins led to a gallery height that is comparable with the size of porphyrin molecules. Molecular simulations showed that the interlayer space is filled with disordered porphyrin units. The porphyrin sulfonate groups interact with the brucite-like layers via dominant electrostatic interactions similarly to layered double hydroxides. The photophysical experiments proved that intercalated anionic Pd porphyrins produce singlet oxygen, O2(1Δg), with long effective lifetimes, suggesting that layered zinc hydroxide salts are good carriers of porphyrin sensitizers.

A zirconium metal-organic framework (MOF) PCN-222 was postsynthetically modified with diphenylphosphinic acid, resulting in an increased stability when activated from water and 4 times higher photosensitizing properties for singlet oxygen production. The phosphinic acid did not compromise the crystallinity of the MOF but made strong bonds with the zirconia secondary building units.