Incorporation of homogeneous organometallic catalysts into metal–organic frameworks for advanced heterogenization: a review

Abstract

Catalysis is among the most promising and fascinating techniques used in various research fields and industries. Heterogeneous catalysts have received more attention than homogeneous catalysts owing to reusability and selectivity issues. Accordingly, metal–organic frameworks (MOFs) are excellent tools for converting homogeneous catalysts into heterogeneous catalysts. MOFs are organic–inorganic hybrid materials with a metal node and an organic linker connected with each other via a coordinate bond that have been developed as encouraging candidates for various applications. The heterogenization of a homogeneous catalyst by developing hybrid materials with MOFs is an attractive new field, combining the properties of both compounds to generate new hybrid heterogeneous catalysts. These new hybrid materials have the benefits of both the organometallic compound and the MOF constituents. As homogeneous catalyst recovery is difficult, this new approach allows the same catalyst to be used, but now exhibiting heterogeneous properties. This review summarizes versatile approaches to the encapsulation of a wide range of organometallic compounds (OMCs) in MOFs to generate OMC@MOFs for catalytic applications. After encapsulation, these OMCs have been used to form nanoparticles (MNP@MOFs) that have been applied to different organic transformations. Although other materials, including zeolites and silica, have also been used for heterogenization, the present review places emphasis on the use of MOFs in the process of heterogenization. The heterogenization of homogeneous organometallic catalysts by incorporation into MOFs using different strategies, MOF selection, OMC selection, and the use of hybrid heterogeneous catalysts in catalytic applications are discussed.