Photocatalytic Selective Bromination of Electron-Rich Aromatic Compounds Using Microporous Organic Polymers with Visible Light

Abstract

Pure organic, heterogeneous, metal-free, and visible light-active photocatalysts offer a more sustainable and environmentally friendly alternative to traditional metal-based catalysts. Here we report a series of microporous organic polymers containing photoactive conjugated organic semiconductor units as heterogeneous photocatalysts for a visible-light-promoted, highly selective bromination reaction of electron-rich aromatic compounds using HBr as a bromine source and molecular oxygen as a clean oxidant. Via a simple Friedel–Crafts alkylation reaction, the microporous organic polymers were obtained by cross-linking of organic semiconductor compounds with defined valence and conduction band positions. The utilization of the simply prepared porous polymer-based photocatalytic systems opens new opportunities toward a sustainable and efficient material design for catalysis.

A Covalent Triazine‐Based Framework Consisting of Donor–Acceptor Dyads for Visible‐Light‐Driven Photocatalytic CO2 Reduction

“…[5] They possess tremendousa dvantages in terms of processability,s ustainability,a nd tunable properties. [5] They possess tremendousa dvantages in terms of processability,s ustainability,a nd tunable properties.…”

“…Conjugated microporous polymers with semiconductor properties have been extensively employed in photocatalytic organic reactions to complementi norganic counterparts. [5] They possess tremendousa dvantages in terms of processability,s ustainability,a nd tunable properties. [5b] Mosta ttractively, their synthetic modularity provides many options for modulating their porosities, band structures,a nd interfacial properties at am olecular level for photochemical applications.…”

CO2‐Triggered Switchable Hydrophilicity of a Heterogeneous Conjugated Polymer Photocatalyst for Enhanced Catalytic Activity in Water

“…TheU V/Vis diffuse reflectance (DR) spectrum of P-BT-DEA showed ab road absorption in the visible region up to 560 nm ( Figure S5a), which is the typical behavior of benzothiadiazole (BT)-anchored porous conjugated polymer photocatalysts. [27] Theo ptical band gap (E g )o f2 .19 eV was derived from the Kubelka-Munk-transformed reflectance spectrum of P-BT-DEA ( Figure S5b). Theelectronic properties of P-BT-DEA were further characterized by cyclic voltammetry (CV; Figure S5c).…”

Benzodithiophenedione‐Based Conjugated Microporous Polymer Catalysts for Aerobic Oxidation Reactions Driven by Visible‐Light

“…It could be noted that CMP-BDD had enough reducing capacity to reduce molecular oxygen into the active species O 2 * À (E red = À 0.56 V vs SCE). [16] In comparison, the HOMO and LUMO level of CMPÀ B lay at 1.65 V and À 0.60 V vs SCE (Figure 2d and Figure S8), respectively. This indicates that the excited CMP-BDD is more easily oxidized by oxygen than CMP-B, resulting in more superoxide anion radicals.…”