Solid-state crystallization achieves selective confinement of metal-organic framework (MOF) nanocrystals within mesoporous materials, thereby rendering active sites more accessible compared to the bulk-MOF and enhancing the chemical and mechanical stability of MOF nanocrystals. (Zr)UiO-66(NH2)/SiO2 hybrid materials were tested as efficient and reusable heterogeneous catalysts for the synthesis of steroid derivatives, outperforming the bulk (Zr)UiO-66(NH2) MOF. A clear correlation between the catalytic activity of the dispersed Zr sites present in the confined MOF, and the loading of the mesoporous SiO2, is demonstrated for steroid transformations.
