Frontispiece: Discrete Ti-O-Ti Complexes: Visible-Light-Activated, Homogeneous Alternative to TiO 2 Photosensitisers
Frontispiece: Discrete Ti-O-Ti Complexes: Visible-Light-Activated, Homogeneous Alternative to TiO 2 Photosensitisers
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卷首文章：离散 Ti-O-Ti 复合物：可见光激活的 TiO 2 光敏剂的均质替代品
DOI：
10.1002/chem.202084363
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发表时间：
2020
期刊：
影响因子：
--
通讯作者：
Behm K
中科院分区：
文献类型：
--
作者：
Behm K
合成了一系列新颖的双三胺双酚盐配合物，并对其进行了全面表征。X射线晶体学研究揭示了钛中心周围扭曲的八面体几何形状，具有连接两种金属的单或双氧桥。这些坚固的、空气和水分稳定的复合物被用作光敏剂，在商业流动反应器中用可见光（420 nm）LED模块照射后产生单线态氧。 所有五种复合物在α-萜品烯的光氧化中均显示出高活性，并在环境温度下在4小时内完全转化为蛔虫素。使用传统TiO 2催化剂的对照实验证明了这些光敏剂对蛔虫素（相对于转化顶伞花烃）的优异选择性。采用游离前配体以及monoclonal类似物的进一步比较研究强调了多金属催化剂中“TiO 2-like”部分的重要性。计算研究用于确定每个配合物的配体到金属电荷转移（LMCT）状态和单重态-三重态间隙的性质，整个系列的紫外-维斯吸收光谱的计算趋势与实验结果吻合良好。
A series of novel bimetallic TiIVamine bis(phenolate) complexes was synthesised and fully characterised. X‐ray crystallography studies revealed distorted octahedral geometries around the Ti centres with single or double oxo‐bridges connecting the two metals. These robust, air‐ and moisture‐stable complexes were employed as photosensitisers generating singlet oxygen following irradiation with visible light (420 nm) LED module in a commercial flow reactor. All five complexes showed high activity in the photo‐oxygenation of α‐terpinene and achieved complete conversion to ascaridole in four hours at ambient temperature. The excellent selectivity of these photosensitisers towards ascaridole (vs. transformation top‐cymene) was demonstrated with control experiments using a traditional TiO2catalyst. Further comparative studies employing the free pro‐ligands as well as a monometallic analogue highlighted the importance of the ‘TiO2‐like’ moiety in the polymetallic catalysts. Computational studies were used to determine the nature of the ligand to metal charge transfer (LMCT) states and singlet–triplet gaps for each complex, the calculated trends in the UV‐vis absorption spectra across the series agreed well with the experimental results.