Strongly Reducing (Diarylamino)anthracene Catalyst for Metal-Free Visible-Light Photocatalytic Fluoroalkylation
Strongly Reducing (Diarylamino)anthracene Catalyst for Metal-Free Visible-Light Photocatalytic Fluoroalkylation
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DOI：
10.1021/acscatal.8b02885
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发表时间：
2018-10-01
期刊：
影响因子：
12.9
通讯作者：
Akita, Munetaka
中科院分区：
文献类型：
--
作者：
Noto, Naoki;Tanaka, Yuya;Akita, Munetaka
定义明确的9，10-双（二（对叔丁基苯基）氨基）蒽是可见光照射下自由基氟烷基化的光催化剂。二芳基胺（供体）-蒽（π共辄系统）-二芳基胺（供体）支架通过相应的卤代蒽与各种二芳基氨基锂的典型钯催化的交叉偶联方案容易地获得。基于蒽的光催化剂表现出高还原能力，导致从相应的电子接受前体产生通用的氟烷基自由基，例如三氟乙基和二氟乙基以及三氟甲基和二氟甲基自由基。催化剂设计强烈影响可见光的吸收能力和对氧化还原刺激的稳定性。对二苯基（2，2，2-三氟乙基）硫鎓三氟甲磺酸盐（diphenyl（2，2，2-trifluoroethyl）sulfonium trifluoroethanesulfonate）无金属光催化苯乙烯氨基三氟乙基化反应机理的研究表明，该反应是通过催化自由基过程而不是自由基链过程进行的。此外，静态猝灭过程涉及从光催化剂到氟烷基化试剂的第一单电子转移（SET）过程。此外，9，10-双（二（对叔丁基苯基）氨基）蒽，一个关键的活性催化物种，具有长寿命和特征的IVCT（间价电荷转移）带的近红外（NIR）区域的le-氧化的阳离子自由基物种，被检测到。从元素战略主动性和绿色化学的角度来看，目前的无贵金属有机光催化体系提供了替代钌基和铱基金属催化剂的关键技术。
Well-defined 9,10-bis(di (p-tert-butylphenyl)-amino)anthracene serves a's a photocatalyst for radical fluoroalkylation under visible light irradiation. The diarylamine (Donor)-anthracene (pi conjugated system)-diarylamine (Donor) scaffolds are easily accessed by typical palladium-catalyzed cross-coupling protocols of the corresponding halogenated anthracenes with various lithium diarylamides. The anthracene-based photocatalyst exhibits high reducing power, leading to generation of versatile fluoroalkyl radicals such as tri- and difluoroethyl and tri- and difluoromethyl radicals from the corresponding electron-accepting precursors. Catalyst design strongly influences the absorption capability of visible light and stability toward redox stimuli. The detailed mechanistic studies on the metal-free photocatalytic amino-trifluoroethylation of styrene with diphenyl(2,2,2-trifluoroethyl)sulfonium trifluoromethanesulfonate suggest that the reaction proceeds via catalytic radical processes rather than radical chain processes. In addition, the static quenching process is involved in the first single-electron-transfer (SET) process from the photocatalyst to the fluoroalkylating reagent. Furthermore, the le-oxidized cationic radical species of 9,10-bis(di(p-tert-butylphenyl)amino)anthracene, a key active catalytic species with long lifetime and a characteristic IVCT (Intervalence Charge Transfer) band in the near IR (NIR) region, is detected. From the viewpoint of elemental strategy initiative and green chemistry, the present noble metal-free organic photocatalytic system provides a pivotal technology to replace ruthenium- and iridium-based metal photocatalysis.