Recent Progress of Amorphous Porous Organic Polymers as Heterogeneous Photocatalysts for Organic Synthesis

Abstract

The establishment of green and environmental friendly sunlight‐driven organic reactions has received increasing attention since the 21st century. By virtue of their functional designability, micromesoporous structure, and thermal/chemical stability, porous organic polymers (POPs) have exhibited enormous promise in photocatalytic organic reactions as ideal potential alternatives to conventional small molecule and inorganic semiconductor catalysts. In particular, amorphous POPs are simplified in terms of preparation conditions and process flow. Herein, various amorphous POP materials based on polymers of intrinsic microporosity, hypercrosslinked polymers, conjugated microporous polymers, and porous aromatic frameworks are reviewed, while typical synthetic strategies are briefly introduced. It also highlights an overview of the research progress in photocatalytic oxidation, coupling, reduction, cycloaddition, and polymerization reactions at home and abroad in recent years. Finally, the challenges and prospects for future research on amorphous POPs are presented.

Blue light-driven selective aerobic oxidation of amines by benzothiadiazole metal–organic framework photocatalysis

“…Benzothiadiazole, an exceptional chromophore, has been extensively utilized in optoelectronic applications, particularly in solar cells 22,23 and photosensitizers. 16,24–26 Moreover, covalent organic frameworks and conjugated microporous polymers, 27 which incorporate benzothiadiazole units, have exhibited remarkable photocatalytic performance in hydrogen evolution 28–32 and various organic transformations. 33,34 Incorporating photoactive benzothiadiazole ligands into MOFs enhances both light absorption and band gap structure.…”

Superlative Porous Organic Polymers for Photochemical and Electrochemical CO2 Reduction Applications: From Synthesis to Functionality

“…35,36 There are also reports of POP materials with different organic functional groups that propel the catalytic efficiency by the formation of conjugated structures. 37,38 The conjugated frameworks and higher specific surface areas of POPs convey a marvelous light-harvesting ability 39,40 that ultimately leads to the achievement of an escalated apparent quantum yield during the photochemical CO 2 RR process. 41 POPs offer an intrinsic propensity for CO 2 transformation into value-added chemical products by providing adequate band structure, which can procure product formation at their conduction band position that has a more negative potential than the reduction potential of chemical products, thus it provides enough potential to leapfrog the reaction barrier during the CO 2 RR process.…”

Ionic Porous Organic Polymer as a Visible-Light Photocatalyst: Efficient Heterogeneous Oxidation of Arylmethylene Compounds and Alcohols Using Molecular Oxygen

“…Immobilization of photocatalysts/sensitizers in porous materials offers the advantage of conducting O 2 -mediated reactions in a heterogeneous phase in a recyclable fashion, obviating disposal of the catalyst at the end of the reaction. Several porous materials, e.g., covalent organic frameworks (COFs), covalent triazine frameworks, porous aromatic frameworks (PAFs), etc., constructed from building blocks like triazine, pyrene, porphyrin, thiophene, sulfone, etc., − have been exemplified as photocatalysts for applications which include water splitting, dye degradation, CO 2 reduction, and catalysis. − In particular, amorphous porous organic polymers (POPs), constructed by covalent polymerization of organic building blocks in a bottom-up fashion, , as photocatalysts are advantageous for the following reasons: (i) they are unrivalled for their physicochemical stabilities, (ii) their band gap energies and absorption in the visible region can be tuned by manipulating the structures of the monomeric building blocks to develop tailored-made materials for photocatalytic applications; (iii) their high surface areas, permanent porosity, and tunable pore size enable control over molecular diffusion and access of the reactants to catalytically active sites; (iv) they permit selectivity in catalytic oxidation reactions, cost-effectiveness, etc. Consequently, POPs have assumed prominence as inextricable materials for diverse applications over the past decade. − …”