scholarly journals Visible Light-Induced Aerobic Oxidative Dehydrogenation of C–N/C–O to C=N/C=O Bonds Using Metal-Free Photocatalysts: Recent Developments

Molecules ◽  
2022 ◽  
Vol 27 (2) ◽  
pp. 497
Author(s):  
Alejandro Torregrosa-Chinillach ◽  
Rafael Chinchilla

Performing synthetic transformation using visible light as energy source, in the presence of a photocatalyst as a promoter, is currently of high interest, and oxidation reactions carried out under these conditions using oxygen as the final oxidant are particularly convenient from an environmental point of view. This review summarizes the recent developments achieved in the oxidative dehydrogenation of C–N and C–O bonds, leading to C=N and C=O bonds, respectively, using air or pure oxygen as oxidant and metal-free homogeneous or recyclable heterogeneous photocatalysts under visible light irradiation.

2020 ◽  
Vol 16 ◽  
Author(s):  
Yuxue Wei ◽  
Honglin Qin ◽  
Jinxin Deng ◽  
Xiaomeng Cheng ◽  
Mengdie Cai ◽  
...  

Introduction: Solar-driven photocatalytic hydrogen production from water splitting is one of the most promising solutions to satisfy the increasing demands of a rapidly developing society. CdS has emerged as a representative semiconductor photocatalyst due to its suitable band gap and band position. However, the poor stability and rapid charge recombination of CdS restrict its application for hydrogen production. The strategy of using a cocatalyst is typically recognized as an effective approach for improving the activity, stability, and selectivity of photocatalysts. In this review, recent developments in CdS cocatalysts for hydrogen production from water splitting under visible-light irradiation are summarized. In particular, the factors affecting the photocatalytic performance and new cocatalyst design, as well as the general classification of cocatalysts, are discussed, which includes a single cocatalyst containing noble-metal cocatalysts, non-noble metals, metal-complex cocatalysts, metal-free cocatalysts, and multi-cocatalysts. Finally, future opportunities and challenges with respect to the optimization and theoretical design of cocatalysts toward the CdS photocatalytic hydrogen evolution are described. Background: Photocatalytic hydrogen evolution from water splitting using photocatalyst semiconductors is one of the most promising solutions to satisfy the increasing demands of a rapidly developing society. CdS has emerged as a representative semiconductor photocatalyst due to its suitable band gap and band position. However, the poor stability and rapid charge recombination of CdS restrict its application for hydrogen production. The strategy of using a cocatalyst is typically recognized as an effective approach for improving the activity, stability, and selectivity of photocatalysts. Methods: This review summarizes the recent developments in CdS cocatalysts for hydrogen production from water splitting under visible-light irradiation. Results: Recent developments in CdS cocatalysts for hydrogen production from water splitting under visible-light irradiation are summarized. The factors affecting the photocatalytic performance and new cocatalyst design, as well as the general classification of cocatalysts, are discussed, which includes a single cocatalyst containing noble-metal cocatalysts, non-noble metals, metal-complex cocatalysts, metal-free cocatalysts, and multi-cocatalysts. Finally, future opportunities and challenges with respect to the optimization and theoretical design of cocatalysts toward the CdS photocatalytic hydrogen evolution are described. Conclusion: The state-of-the-art CdS for producing hydrogen from photocatalytic water splitting under visible light is discussed. The future opportunities and challenges with respect to the optimization and theoretical design of cocatalysts toward the CdS photocatalytic hydrogen evolution are also described.


Nanoscale ◽  
2021 ◽  
Author(s):  
Hu Liu ◽  
Mengqi Shen ◽  
Peng Zhou ◽  
Zhi Guo ◽  
Xinyang Liu ◽  
...  

Developing an efficient single component photocatalyst for overall water splitting under visible-light irradiation is extremely challenging. Herein, we report a metal-free graphitic carbon nitride (g-CxN4)-based nanosheet photocatalyst (x = 3.2,...


Synlett ◽  
2018 ◽  
Vol 30 (07) ◽  
pp. 777-782 ◽  
Author(s):  
Clément Ghiazza ◽  
Cyrille Monnereau ◽  
Lhoussain Khrouz ◽  
Maurice Médebielle ◽  
Thierry Billard ◽  
...  

We demonstrated that the shelf-stable reagent trifluoromethyl tolueneselenosulfonate can be involved in radical trifluoromethylselenylation. Upon visible-light irradiation, the homolysis of the reagent could take place at room temperature. This finding is explored for unprecedented C(sp2)–SeCF3 and C(sp3)–SeCF3 processes under transition-metal-free conditions. Mechanistic investigations, including cyclic voltammetry, luminescence measurement, and EPR studies, allowed the proposal of plausible mechanisms.1 Introduction.2 Reactivity of Reagent I with Diazonium Salts3 Reactivity of Reagent I with Alkenes and Alkynes4 Conclusion


2018 ◽  
Vol 47 (35) ◽  
pp. 12188-12196 ◽  
Author(s):  
Lu Chen ◽  
Huijuan Huang ◽  
Yuanhui Zheng ◽  
Wenhao Sun ◽  
Yi Zhao ◽  
...  

Noble-metal-free Ni3N/g-C3N4 heterojunctions that show high photocatalytic hydrogen evolution activity comparable to platinized g-C3N4 were successfully synthesized.


Synthesis ◽  
2020 ◽  
Vol 53 (01) ◽  
pp. 123-134
Author(s):  
Constantin Czekelius ◽  
Lucas Helmecke ◽  
Michael Spittler ◽  
Bernd M. Schmidt

A comparison of two catalytic, metal-free iodoperfluoro­alkylation protocols is presented. Frustrated Lewis pairs [ t Bu3P/B(C6F5)3] or phosphines/phosphites under visible light irradiation efficiently mediate the functionalization of non-activated alkenes and alkynes. A comprehensive account of the corresponding substrate scopes as well as insights into the mechanistic details of both reaction pathways are provided.


2020 ◽  
Vol 22 (6) ◽  
pp. 1906-1910 ◽  
Author(s):  
Xinxing Gong ◽  
Min Yang ◽  
Jin-Biao Liu ◽  
Fu-Sheng He ◽  
Xiaona Fan ◽  
...  

A metal-free route to alkynyl sulfones under photoinduced conditions is accomplished, starting from 4-alkyl Hantzsch esters, sulfur dioxide, and alkynyl bromides under visible light irradiation at room temperature.


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