Preparation of Hydrophilic Conjugated Microporous Polymers for Efficient Visible Light-Driven Nicotinamide Adenine Dinucleotide Regeneration and Photobiocatalytic Formaldehyde Reduction

Abstract

Recently, photobiocatalysis with oxidoreductases, inspired by natural photosynthesis, has drawn increasing attention due to its high catalytic efficiency and selectivity. However, although an important cofactor for the activation of redox enzymes, nicotinamide adenine dinucleotide (NADH) suffers from the drawbacks of cost and limited stability. Moreover, the design of an effective NADH regeneration system remains a huge challenge. Here, we report a visible light-driven conjugated microporous polymer DBTS-CMP1 for the heterogeneous photocatalytic regeneration of NADH. Thanks to various improved properties, such as extended visible light absorption, adequate fluorescence lifetime, enhanced wettability, and rapid charge separation and transfer, an NADH regeneration efficiency of 84% in 45 min was achieved with DBTS-CMP1. In addition, the small molecule model compound DBTS-Ph2, which shares similar structural motifs, was also designed to further study the photoinduced electron transfer process. The strong coordination interaction between dibenzo-[b,d]­thiophene sulfone and the Rh metal center, as reflected in fluorescence quenching, cyclic voltammetry, and Fourier-transform infrared spectroscopy measurements, plays an essential role in electron transfer from the photocatalyst to the Rh complex, thus endowing DBTS-CMP1 with a high reaction conversion and selectivity (100%) for 1,4-NADH regeneration. Finally, a photobiocatalytic system was constructed by incorporating NADH-dependent alcohol dehydrogenase for the reduction of formaldehyde into methanol. A total amount of 2.23 mM methanol with a turnover number of 2.23 mmol g–1 was obtained after 95 min in the photobiocatalytic system, indicating the high photostability and biocompatibility of our DBTS-CMP1 photocatalyst.

Development of an Ionic Porphyrin-Based Platform as a Biomimetic Light-Harvesting Agent for High-Performance Photoenzymatic Synthesis of Methanol from CO2

“…Results showed that the methanol concentration was maintained after six rounds of experiments, indicating that the enzyme activity was maintained and that the enzyme leakage was negligible. For most published enzyme-immobilized systems, ,, the process typically involved chemical reaction and an unfavorable solvent, which is harmful for enzyme activity and stability. All in all, such a photosynthesis system showed outstanding performance on methanol production with a facile synthesis, which was a promising way to produce methanol driven by unlimited solar energy.…”

Effect of the cross-linker length of thiophene units on photocatalytic hydrogen production of triazine-based conjugated microporous polymers

“…After that, various types of organic polymers for photocatalytic hydrogen evolution have been widely studied, such as conjugated microporous polymers (CMPs), linear conjugated polymers and covalent organic framework materials, etc. 12–14 Among them, CMPs is emerging class of organic porous materials with large π-conjugated framework and many nanoscale pores. 15–17 More importantly, the energy band structure, optical absorption and pore size of CMPs can be fine-tuned by changing the chemical structure.…”

Semi-Hydrogenation of Alkynes by a Tandem Photoredox System Free of Noble Metal

“…Sunlight provides sustainable energy to drive challenging chemical reactions with semiconductor materials through an environmentally friendly route. [14][15][16][17][18][19] Substantial research efforts have mainly focused on promoting exciton dissociation of the semiconductors by means of textural tailoring, optical property optimization, and surface kinetic control. [20][21][22] Recently, attention has been paid to hybrid photocatalysis, which accelerates charge separation by establishing electron transport chains between semiconductor and molecular catalyst, provides a feasible and efficient photocatalytic platform for continuous electron output to substrate, and is fully accessible to the toolbox of valuable organic synthesis.…”