Highly selective electrosynthesis of imines via electroreduction coupling of nitroarenes with aryl aldehydes on Co_(9)S_(8)with positively charged sulfur vacancies  

硫空位促进硝基芳烃与芳基醛电化学还原偶联高选择性电合成亚胺

作　　者：Dianke Xie Tianyi Yang Chongyang Ma Chung-Li Dong Shuangyin Wang Yuqin Zou 谢典科;杨天仪;马重阳;董崇礼;王双印;邹雨芹(湖南大学化学化工学院,先进催化教育部工程研究中心,化学生物传感与计量学国家重点实验室,湖南长沙410082;淡江大学物理系,台湾新北25137)

机构地区：[1]State Key Laboratory of Chemo/Bio-Sensing and Chemometrics,College of Chemistry and Chemical Engineering,Advanced Catalytic Engineering Research Center of the Ministry of Education,Hunan University,Changsha 410082,Hunan,China [2]Department of Physics,Tamkang University,New Taipei City 25137,Taiwan,China

出　　处：《Chinese Journal of Catalysis》2024年第10期206-216,共11页催化学报（英文）

基　　金：国家重点研发计划(2020YFA0710000);国家自然科学基金(22122901,22425021);湖南省自然科学基金(2021JC0008,2021RC3054).

摘　　要：The electrocatalytic synthesis of imines through the reductive imination of nitroarenes with aldehydes is a facile,environmentally friendly,and valuable process.In this study,high selectivity electrosynthesis of imines was realized through the electrocatalytic C-N coupling reaction between nitroarenes and aryl aldehydes on Co_(9)S_(8)nanoflowers with rich sulfur vacancies(Co_(9)S_(8)-Vs).Comparative experiments revealed that positively charged sulfur vacancies play a pivotal role in boosting catalytic selectivity towards imines.Electron-deficient sulfur vacancies intensified the adsorption of negatively charged Ph-NO_(2),thereby enhancing the conversion rate of the electrochemical nitrobenzene-reduction reaction(eNB-RR).Simultaneously,sulfur vacancies augmented the adsorption capability of negatively charged Ph-CHO,enriching Ph-CHO species at the electrode interface and expediting the Schiff base condensation reaction rate.The experimental results show that the reaction conditions can satisfy the different nitroarenes and aryl aldehydes in the electrocatalytic aqueous-phase system under mild conditions to obtain the corresponding imine products in high selectivity.This study provides a facile and environmentally friendly pathway for future electrocatalytic synthesis of imine.亚胺是一类具有碳氮双键C=N)的有机化合物,是合成化学中重要的反应物和中间体,广泛应用于药品、农用化学品和其他精细化学品等生物活性化合物的合成.从硝基苯合成功能化亚胺在现代合成化学中具有重要意义.然而,传统的亚胺合成方法通常需要使用氢气和大量芳香族化合物溶剂,这会导致能源损耗和环境污染,因此,需要开发更加先进绿色的合成策略.近年来,电化学硝基苯还原反应因其过程可持续、效率高、反应条件温和等特点而备受关注.研究人员将硝基化合物与羰基化合物结合,生成了硝酮和亚胺等更多有价值的C-N偶联产物.由于竞争反应(如硝基苯的自偶联和苯甲醛的还原)的发生和可逆的希夫碱缩合过程限制了亚胺的收率,实现高收率的电催化合成亚胺仍然是一个挑战.因此,迫切需要设计一种创新的电催化反应体系来加速偶联反应提高亚胺的产率本文在常温常压条件下采用富含硫空位的CoS:纳米花催化剂(Co_(9)S_(8)-Vs),在水相介质中通过硝基芳烃和芳基醛之间的电催化C-N偶联反应,实现了亚胺的高选择性电合成.电化学晶体石英微天平(EQCM)测试和第一性原理(DFT)计算结果表明,引入带正电的硫空位可以有效地增强带负电的硝基苯和苯甲醛的吸附,促进了电化学硝基苯还原反应(eNB-RR)的速率和转化率,此外,苯甲醛的吸附增强导致其在电极界面积聚,从而加快了席夫碱缩合反应速率,提高了亚胺生成的选择性.最后,生成的亚胺容易在催化剂界面解吸,提供了额外的活性位点,间接促进了eNB-RR的速率,从而提高了硝基苯的转化率.研究结果还表明,该电催化合成亚胺化合物的方法对各种芳基醛和硝基芳烃的C-N偶联反应具有普遍的适用性.在Co_(9)S_(8)-Vs阴极催化剂上考察了硝基苯与苯甲醛的克级电还原偶联制备亚胺产物的可行性,在0VRHE条件下,10mmol硝基苯的转化�

关 键 词：Co-based electrocatalyst Sulfur-vacancies Electrocatalysis Electroreduction coupling 

分 类 号：O62[理学—有机化学]