Metal-Ion/Metal Nanoparticle-Anchored Porous Organic Polymers as Efficient Catalysts for Organic Transformations - A Recent Overview.

Abstract

Porous organic polymers are porous materials that are interlinked with organic building blocks by strong covalent bonds. The functional groups on the building blocks can be carefully chosen to obtain a POP with desired functionalities. In certain cases, the pores or voids interact with the organic molecules via non-covalent interactions and hence they serve as catalytic centers. In many cases, pristine POPs themselves were evaluated as heterogeneous catalysts for their catalytic activity. The inner functional groups of POPs act as a ligand or interact with metal ions/metal nanoparticles and hence a wide range of metal-ion-anchored POPs or metal nanoparticle-loaded POPs were reported. These metal-ion-anchored POPs can catalyze different organic reactions as that of pristine metal-based catalysis following a heterogeneous pathway. In this type of catalysis, POP plays an important role, i. e., it serves as a carbon matrix, and interacts with organic molecules via non-covalent interactions, further in metal/metal-ion-anchored POPs, the metal concentration is highly reduced and the organic transformation effectively takes place at the interface of metal/carbon matrix. Herein, we discuss the recent developments on metal-ion/metal nanoparticle loaded POPs and their role in various organic transformations such as C-C coupling reactions, borrowing hydrogen reactions, CO2 transformations, hydroformylations reactions, oxidation of alkynes to 1,2-diketones and C-H arylation reactions.