Asymmetric photocatalysis over robust covalent organic frameworks with tetrahydroquinoline linkage  

新型超稳定四氢喹啉连接的共价有机骨架材料的制备及其不对称光催化性能

作　　者：Chunzhi Li Yinhua Ma Haoran Liu Lin Tao Yiqi Ren Xuelian Chen He Li Qihua Yang 李纯志;马银华;刘浩然;陶琳;任亦起;陈雪莲;李贺;杨启华(中国科学院大连化学物理研究所催化基础国家重点实验室,辽宁大连116023;中国科学院大学,北京100049;中国科学院大连化学物理研究所分子反应动力学国家重点实验室,辽宁大连116023)

机构地区：[1]State Key Laboratory of Catalysis,iChEM,Dalian Institute of Chemical Physics,Chinese Academy of Sciences,Dalian 116023,Liaoning,China [2]University of Chinese Academy of Sciences,Beijing 100049,China [3]State Key Laboratory of Molecular Reaction Dynamics,Dalian Institute of Chemical Physics,Chinese Academy of Sciences,Dalian 116023,Liaoning,China

出　　处：《Chinese Journal of Catalysis》2020年第8期1288-1297,共10页催化学报（英文）

基　　金：国家自然科学基金(21733009,21621063);中国科学院战略性先导科技专项(XDB17020200).

摘　　要：The asymmetric photocatalytic organic synthesis(APOS)process is a sustainable and environmentally benign method for the production of optically active chemicals with sunlight as an energy source.However,it still lacks efficient semiconductors with tunable band structures and has a low recycling stability.Herein,we report the synthesis of tetrahydroquinoline-linked covalent organic frameworks(QH-COFs)with irreversible tetrahydroquinoline linkage as efficient semiconductors for the visible-light-driven asymmetricα-alkylation of aldehydes by merging with a chiral secondary amine.Up to 94%ee was obtained over QH-COFs,and the activity of QH-COFs was significantly higher than those of inorganic semiconductors(e.g.,Ti O2,Bi VO4,and WO3)under similar conditions,which is mainly attributed to their narrow band gap and suitable band edge.As far as we know,QH-COFs are the most active semiconductors for asymmetricα-alkylation of aldehydes ever reported.The QH-COFs were prepared via a one-pot Povarov cascade imine formation and cycloaddition reaction using Sc(OTf)3/Yb(OTf)3 as Lewis acid catalysts.Attributed to the tetrahydroquinoline linkage,QH-COFs showed extremely high recycling stability,which made practicals application possible.This work not only opens up a new avenue for asymmetric photocatalysis but also provides an efficient and general method for the construction of robust COFs.不对称光催化有机合成是一种可持续的、环境友好的以太阳光为能源生产光学活性化学品的方法.绝大多数不对称光催化有机合成体系是由有机染料或无机半导体作为捕光材料与手性催化剂耦合构成.然而通常面临有机染料吸收谱带窄、光腐蚀严重,以及无机半导体材料的能带结构和带隙难以调控等问题.直到目前,仍然缺乏具有可调节带隙结构和高循环稳定性的半导体材料.最近,一类通过共价键连接形成、具有晶态有序结构的共价有机骨架材料(COFs)被报道用于光催化有机合成.但多数COFs材料均由可逆的化学键(如B-O-B键、-C=N键等)构成,其化学稳定性和光稳定性有待提升.目前已报道的一些稳定COFs均基于特殊的单体结构或通过后修饰策略制备,其合成路线过长并需要对单体进行额外的修饰.本文中,我们发展了一种具有普适性的通过不可逆四氢喹啉连接的COFs材料的制备方法,并考察了该材料在不对称光催化反应中的活性和稳定性.我们以1,3,5-三(4’-醛基苯基)苯、1,3,5-三(4’-氨基苯基)苯(或联苯胺)和乙烯基乙醚为原料,以三氟甲磺酸钪和三氟甲磺酸镱为催化剂,通过一锅法波瓦罗夫反应制备了两种以不可逆四氢喹啉连接的新型共价有机骨架材料QH-COFs.QH-COFs材料表现出了极高的化学稳定性,在浓硫酸、浓盐酸、三氟乙酸或氢氧化钠溶液中浸泡三天,其比表面积和结晶性均没有发生明显变化.QH-COFs(作为半导体)和手性二级胺(为手性催化剂)在可见光下可高效催化醛的不对称α烷基化反应,ee值高达94%.由于QH-COFs具有窄的禁带宽度和适合的能带结构,在相同条件下,QH-COFs的活性明显优于无机半导体(如二氧化钛、钒酸铋、三氧化钨等).QH-COFs是迄今为止报道的在可见光下催化醛的不对称α烷基化反应活性最高的半导体材料.由于四氢喹啉结构的存在,QH-COFs具有极高的循环

关 键 词：PHOTOCATALYSIS Covalent organic frameworks Tetrahydroquinoline linkage Asymmetric catalysis Ultrastability 

分 类 号：O626.323[理学—有机化学]