Enhanced Reducibility via Altering Exciton Binding Energy of Conjugated Microporous Polymers for Photocatalytic Reduction

Abstract

Visible-light-driven organic transformations, such as photocatalytic reductive dehalogenation, are highly significant but remain challenging to implement because of the insufficient charge separation. Herein, we report a facile strategy to realize heterogeneous and high-efficiency photocatalytic dehalogenation under mild conditions via tuning the exciton binding energy of conjugated microporous polymers (CMPs) with an alternating electron donor (D)–acceptor (A) structural motif. The integration of acceptors, especially strong ones (sA), into the conjugated polymer scaffolds minimized the exciton binding energy, suppressed charge carrier recombination, and facilitated the charge transfer effectively. CMP-CSU11, featuring an alternative D–sA skeleton with the lowest exciton binding energy, exhibited a superior photocatalytic dehalogenation efficiency over 99% in only 50 min, surpassing the state-of-the-art photoreductive dehalogenation catalysts, enabling a broad scope of substrates (14 examples), and possessing extraordinary recyclability. This work provides an effective strategy based on intramolecular charge transfer engineering to develop heterogeneous photocatalysts for task-specific organic transformation.

Carbazole-Based Porous Organic Polymers with Ag(I) Doping and Derived Porous Carbon for Enhanced Adsorption of Polycyclic Aromatic Hydrocarbons

“…The PXRD patterns proved P1 and P2 are amorphous powders (Figure a), which may be caused by the irreversible Suzuki coupling reaction. , P1 and P2 showed high thermal stabilities with TG analysis (Figure b). The polymers can keep their inherent skeletons at 300 °C because of the rigid stable skeletons.…”

Electric effects reinforce charge carrier behaviour for photocatalysis

“…Notably, MOFs have many active sites on the surface, 106 and the complex exciton behavior during photocatalysis is a great challenge for further deeper investigation of the exciton effect. Additionally, conjugated microporous polymers (CMPs) can be used for efficient photocatalysis by introducing extended π-conjugated systems 107 and modulating the alternating electron D–A structural motifs 108 both of which can effectively reduce E b . Covalent triazine frameworks (CTFs) are operated by in-built dipole control to reduce E b of thiophene-rich CTF and promote exciton dissociation.…”

Robust Nitrogen-Doped Microporous Carbon via Crown Ether-Functionalized Benzoxazine-Linked Porous Organic Polymers for Enhanced CO2 Adsorption and Supercapacitor Applications

“…Hyper-cross-linked polymers (HPP), covalent triazine frameworks (CTFs), covalent organic frameworks (COFs), and conjugated microporous polymers (CMPs) represent four instances of porous organic polymers (POPs) characterized by substantial specific surface areas and well-defined pores, explored for a broad range of applications. − These applications encompass chemical sensing, energy storage, hydrogen evolution, gas capture, and separation, as well as photocatalysis. − Schiff base and coupling reactions [including Suzuki, Yamamoto, and Sonogashira] are among the chemical reactions often used in POP synthesis. The purpose of these reactions is usually to add covalent bonds to the polymer structure, such as boroxine, imine, and triazine units. − The optoelectronic and thermal characteristics of POPs can be customized for potential applications by employing diverse synthesis techniques and incorporating various building blocks. − In the realms of chemical sensing, photocatalysis, CO 2 adsorption, batteries, supercapacitors, and H 2 generation, these POPs have exhibited promising performance. , Some groups have successfully modified POPs by introducing additional functional groups, including amine/amide, quinolone, oxazole, and thiazole, through solid-state chemical transformation processes. − For example, the imine-linked covalent organic framework (COF) can undergo a transition into thiocarbamate and carbamate-linked COFs with increased S BET . Utilizing reduction and Mannich reaction, certain researchers have employed benzoxazine-linked COF, exhibiting an S BET exceeding 650 m 2 /g .…”