Strong Lewis acid air-stable cationic titanocene perfluoroalkyl(aryl)sulfonate complexes as highly efficient and recyclable catalysts for C-C bond forming reactions
Strong Lewis acid air-stable cationic titanocene perfluoroalkyl(aryl)sulfonate complexes as highly efficient and recyclable catalysts for C-C bond forming reactions
复制标题
强路易斯酸空气稳定阳离子二茂钛全氟烷基（芳基）磺酸盐络合物作为 C-C 键形成反应的高效且可回收的催化剂
DOI：
10.1039/c4dt00549j
复制
发表时间：
2014-08-14
影响因子：
4
通讯作者：
Xu, Xinhua
中科院分区：
文献类型：
--
作者：
Li, Ningbo;Wang, Jinying;Xu, Xinhua
通过分别用全氟戊磺酸银（C₅F₁₇SO₃Ag）、全氟丁磺酸银（C₄F₉SO₃Ag）和五氟苯磺酸银（C₆F₅SO₃Ag）处理二氯二茂钛（Cp₂TiCl₂），成功合成了一系列对空气稳定的强路易斯酸二茂钛全氟烷基（芳基）磺酸盐配合物Cp₂Ti(OH₂)₂(OSO₂X)₂·THF（X = C₅F₁₇，1·THF；X = C₄F₉，2·H₂O·THF；X = C₆F₅，3 ）。与众所周知的二茂钛双（三氟甲磺酸盐）不同，这些配合物在空气中放置三个月无变化。热重 - 差示扫描量热（TG - DSC）分析表明，1·THF、2·H₂O·THF和3分别在230℃、220℃和280℃下热稳定。电导率测量表明，这些配合物在乙腈溶液中发生离子解离。X射线分析结果证实2·H₂O·THF和3为阳离子型。电子顺磁共振（ESR）光谱表明，1·THF的路易斯酸性（1.06电子伏特）高于Sc³⁺（1.00电子伏特）和Y³⁺（0.85电子伏特）。紫外 - 可见（UV - Vis）光谱表明，由于10 - 甲基吖啶酮与2·H₂O·THF之间形成强配合物，出现了明显的红移。荧光光谱表明，2的路易斯酸性（λem = 477纳米）高于Sc³⁺（λem = 474纳米）。这些配合物在各种碳 - 碳键形成反应中表现出高催化能力。此外，它们具有良好的可重复使用性。与1·THF相比，2·H₂O·THF和3具有更高的溶解性和更好的催化活性，将在有机合成中找到广泛应用。
A series of strong Lewis acid air-stable titanocene perfluoroalkyl(aryl)sulfonate complexes Cp2Ti(OH2)(2)-(OSO2X)(2)THF (X = C5F17, 1.THF; X = C4F9, 2.H2O"THF; X = C6F5, 3) were successfully synthesized by the treatment of Cp2TiCl2 with C5FE7S03Ag, C4F9S03Ag and C6F5S03Ag, respectively. In contrast to wellknown titanocene bis(triflate), these complexes showed no change in open air over three months. TG-DSC analysis showed that 1.THF, 2"H20.THF and 3 were thermally stable at 230 degrees C, 220 degrees C and 280 degrees C, respectively. Conductivity measurements showed that these complexes underwent ionic dissociation in CH3CN solution. X-ray analysis results confirmed that (2).H(2)0.THF and 3 were cationic. ESR spectra showed that the Lewis acidity of 1.THF (1.06 eV) was higher than that of Sc3+ (1.00 eV) and Y3+ (0.85 eV). UVNis spectra showed a significant red shift due to the strong complex formation between 10-methylacridone and 2.H20.TH F. Fluorescence spectra showed that the Lewis acidity of 2 (gem = 477 nm) was higher than that of Sc3+ (Am = 474 nm). These complexes showed high catalytic ability in various carbon-carbon bond forming reactions. Moreover, they show good reusability. Compared with 1"THF, (2).H2O-THF and 3 exhibit higher solubility and better catalytic activity, and will find broad applications in organic synthesis.