Triplet-triplet annihilation(TTA) upconversion-based materials have potential application in the broad range of research areas, including photocatalysis and life sciences. However, near-infrared(NIR)-to-blue upconvert...Triplet-triplet annihilation(TTA) upconversion-based materials have potential application in the broad range of research areas, including photocatalysis and life sciences. However, near-infrared(NIR)-to-blue upconverted emission is preferred for most of the practical applications, but developing a NIR-to-blue TTA upconversion system is a challenging task in photochemistry. In this work, a thermally activated delayed fluorescence(TADF) material with intense visible-to-NIR absorption is demonstrated that shows a longer triplet state lifetime(32 μs) and high triplet state energy(E_(T)= 1.55 e V). For the first time, a heavy atomfree NIR(λ_(ex)> 650 nm) to blue(λ_(em)< 460 nm) TTA upconversion system was devised, employing the dimeric borondifluoride curcuminoid TADF material as triplet photosensitizer(PS) and a large anti-Stokes shift(0.88 e V) along with moderate upconversion yield was achieved. Our work provides the solution and guidance for the future development of purely organic heavy atom-free NIR activating TTA upconversion system for a wide array of applications.展开更多
近年来,氢硅烷参与的光催化自由基反应是有机合成领域的研究热点.文章系统综述了可见光催化下氢硅烷作为硅源合成有机硅化合物及作为卤原子转移(halogen atom transfer,XAT)试剂的自由基反应.研究表明,可见光催化下,氢硅烷能在温和条件...近年来,氢硅烷参与的光催化自由基反应是有机合成领域的研究热点.文章系统综述了可见光催化下氢硅烷作为硅源合成有机硅化合物及作为卤原子转移(halogen atom transfer,XAT)试剂的自由基反应.研究表明,可见光催化下,氢硅烷能在温和条件下产生硅自由基,通过加成、取代等反应途径,高效构建了碳硅键.氢硅烷能与卤代烷烃发生单电子转移反应,生成烷基自由基中间体,并与烯烃、芳烃等富电子底物发生加成、取代等反应,最终实现交叉偶联这一重要转化过程.文章也对未来研究方向进行了展望:1)深入探索氢硅烷与羰基化合物的反应体系,解决该领域研究匮乏的问题;2)开发兼具高选择性、优异稳定性且经济的新型光催化剂;3)将光催化与过渡金属催化相结合,添加手性配体,实现不对称自由基反应的突破性进展.展开更多
基金the National Natural Science Foundation of China (Nos. 21975053, 21975055, U2001222)Guangdong Basic and Applied Basic Research Foundation (Nos. 2019B1515120023, 2022B1515020041)Guangdong Province Universities and Colleges Pearl River Scholar Funded Scheme (2019) for financial support。
文摘Triplet-triplet annihilation(TTA) upconversion-based materials have potential application in the broad range of research areas, including photocatalysis and life sciences. However, near-infrared(NIR)-to-blue upconverted emission is preferred for most of the practical applications, but developing a NIR-to-blue TTA upconversion system is a challenging task in photochemistry. In this work, a thermally activated delayed fluorescence(TADF) material with intense visible-to-NIR absorption is demonstrated that shows a longer triplet state lifetime(32 μs) and high triplet state energy(E_(T)= 1.55 e V). For the first time, a heavy atomfree NIR(λ_(ex)> 650 nm) to blue(λ_(em)< 460 nm) TTA upconversion system was devised, employing the dimeric borondifluoride curcuminoid TADF material as triplet photosensitizer(PS) and a large anti-Stokes shift(0.88 e V) along with moderate upconversion yield was achieved. Our work provides the solution and guidance for the future development of purely organic heavy atom-free NIR activating TTA upconversion system for a wide array of applications.
文摘近年来,氢硅烷参与的光催化自由基反应是有机合成领域的研究热点.文章系统综述了可见光催化下氢硅烷作为硅源合成有机硅化合物及作为卤原子转移(halogen atom transfer,XAT)试剂的自由基反应.研究表明,可见光催化下,氢硅烷能在温和条件下产生硅自由基,通过加成、取代等反应途径,高效构建了碳硅键.氢硅烷能与卤代烷烃发生单电子转移反应,生成烷基自由基中间体,并与烯烃、芳烃等富电子底物发生加成、取代等反应,最终实现交叉偶联这一重要转化过程.文章也对未来研究方向进行了展望:1)深入探索氢硅烷与羰基化合物的反应体系,解决该领域研究匮乏的问题;2)开发兼具高选择性、优异稳定性且经济的新型光催化剂;3)将光催化与过渡金属催化相结合,添加手性配体,实现不对称自由基反应的突破性进展.
