Photoelectric properties of aromatic triangular tri-palladium complexes and their catalytic applications in the Suzuki-Miyaura coupling reaction
Photoelectric properties of aromatic triangular tri-palladium complexes and their catalytic applications in the Suzuki-Miyaura coupling reaction
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芳香族三角三钯配合物的光电性质及其在铃木宫浦偶联反应中的催化应用
DOI：
10.1039/d1dt01597d
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发表时间：
2021-07-21
影响因子：
4
通讯作者：
Liu, Xiang
中科院分区：
文献类型：
--
作者：
Li, Xujun;Li, Jia;Liu, Xiang
研究了取代三苯基膦和硫硒配体负载芳香三角形三钯配合物1-4（简称[Pd-3](+)）的光电性质和催化活性。[Pd-3]（+）在CH3CN-(Bu4NPF6)- bu -n中的循环伏安表现为单一的准可逆波，这与它们的鲁棒性一致，为它们在催化中的电子转移过程提供了初步的证据。在267 nm激发下，[Pd-3]（+）在550和780 nm处表现出较强的比例荧光，温度梯度从77 K到287 K。这些特殊的三角形三钯配合物在Suzuki Miyaura偶联反应中表现出优异的催化活性和与芳基碘化物的专属反应性。研究了取代基对芳基碘化物和芳基硼酸（包括吡啶、吡嗪和噻吩等杂芳烃）的电子位阻和位阻效应，大多数底物的产率高达99%。与选择性环氧合酶-2 （COX-2）抑制剂类似的（2-[1,1'-联苯]-2-基苯并噻唑）也在我们的三钯催化剂上合成，分离收率达到了94%。催化过程的研究表明，该反应的机理可能是芳基碘化物中的碘取代[N-3]（+）上的硫配体，有利于C-I键能的匹配。
The photoelectric properties and catalytic activities of substituted triphenylphosphine and sulfur/selenium ligand supported aromatic triangular tri-palladium complexes 1-4, abbreviated as [Pd-3](+), were investigated. The cyclic voltammogram of [Pd-3](+) in CH3CN-(Bu4NPF6)-Bu-n showed a single quasi-reversible wave which was consistent with their robust property and provided preliminary proof for their electron transfer processes in catalysis. With excitation at 267 nm, [Pd-3](+) exhibited strong ratiometric fluorescence at 550 and 780 nm at a temperature gradient from 77 K to 287 K. These peculiar triangular tri-palladium complexes showed excellent catalytic activities and exclusive reactivity with aryl iodides over the other halogenated aromatics in the Suzuki Miyaura coupling reaction. The electronic and steric hindrance effects of substituents on the aryl iodides and aryl boronic acids including heteroaromatics like pyridine, pyrazine and thiophenes were explored and most substrates achieved up to 99% of yields. (2-[1,1'-Biphenyl]-2-ylbenzothiazole) which was analogous to the selective cyclooxygenase-2 (COX-2) inhibitors was also synthesized with our tri-palladium catalyst and gave good isolated yield (94%). The study of the catalytic process revealed that the mechanism of the reaction may involve the replacement of the sulphur ligand on [N-3](+) by iodine from aryl iodides, which was beneficial for the matching of C-I bond energy.