C-H Bond Activation and C-C Coupling of Methane on a Single Cationic Platinum Center: A Spectroscopic and Theoretical Study.
C-H Bond Activation and C-C Coupling of Methane on a Single Cationic Platinum Center: A Spectroscopic and Theoretical Study.
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DOI：
10.1021/acs.inorgchem.2c01328
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发表时间：
2022-07-25
影响因子：
4.6
通讯作者：
Armentrout, P. B.
中科院分区：
文献类型：
--
作者：
Wensink, Frank J.;Roos, Noa;Bakker, Joost M.;Armentrout, P. B.
我们光谱研究了一个和多个甲烷分子与Pt+离子反应产生的活化产物。Pt+离子通过激光烧蚀金属靶形成，并在超声膨胀中冷却到电子基态。然后将离子转移到室温离子阱中，在那里它们在氩气缓冲气体中以各种分压与甲烷反应。观察到的产物质量为[Pt，C，2 H]+、[Pt，2C，4 H]+、[Pt，4C，8H]+和[Pt，2C，O，6 H]+，其是质量分离的，并使用红外多光子解离（IRMPD）光谱，采用用于腔内实验的自由电子激光器（FELICE）进行表征。[Pt，2C，4 H]+和[Pt，4C，8H]+的光谱有几个定义明确的频带，并与密度泛函理论计算的几种可能的产物结构的光谱相比，导致明确的分配与乙烯配体的物种，证明Pt+介导的C-C耦合涉及多达四个甲烷分子。这些发现与早期的实验形成对比，在早期的实验中，Pt+离子在流管型反应通道中在显著更高压力的氦气缓冲气体下反应，导致形成Pt（CH 3）2+产物。我们的DFT计算显示，相对于C-C耦合所需的PtCH 2 + + CH 4反应物，反应势垒为+0.16 eV。在两个实验中的不同结果表明，在早期的工作中较高的压力可以动力学捕获的二甲基产品，而较低的压力和较长的停留时间在离子阱允许反应进行，导致乙烯的形成和二氢消除。甲烷与气相原子铂阳离子在室温离子阱中反应，并且使用用于腔内实验的自由电子激光器（FELICE）的IR光来表征所得产物离子。我们观察到PtCH ~（2+）、Pt（ethene）~（2+）和Pt（ethene）~（2+）的形成。这些发现证明了甲烷分子的C-H键活化和C-C偶联。
We spectroscopically investigated the activation products resulting from reacting one and multiple methane molecules with Pt+ ions. Pt+ ions were formed by laser ablation of a metal target and were cooled to the electronic ground state in a supersonic expansion. The ions were then transferred to a room temperature ion trap, where they were reacted with methane at various partial pressures in an argon buffer gas. Product masses observed were [Pt,C,2H]+, [Pt,2C,4H]+, [Pt,4C,8H]+, and [Pt,2C,O,6H]+, which were mass-isolated and characterized using infrared multiple-photon dissociation (IRMPD) spectroscopy employing the free electron laser for intra-cavity experiments (FELICE). The spectra for [Pt,2C,4H]+ and [Pt,4C,8H]+ have several well-defined bands and, when compared to density functional theory-calculated spectra for several possible product structures, lead to unambiguous assignments to species with ethene ligands, proving Pt+-mediated C–C coupling involving up to four methane molecules. These findings contrast with earlier experiments where Pt+ ions were reacted in a flow-tube type reaction channel at significantly higher pressures of helium buffer gas, resulting in the formation of a Pt(CH3)2+ product. Our DFT calculations show a reaction barrier of +0.16 eV relative to the PtCH2+ + CH4 reactants that are required for C–C coupling. The different outcomes in the two experiments suggest that the higher pressure in the earlier work could kinetically trap the dimethyl product, whereas the lower pressure and longer residence times in the ion trap permit the reaction to proceed, resulting in ethene formation and dihydrogen elimination. Methane is reacted with gas-phase atomic platinum cations in a room temperature ion trap, and the resulting product ions are characterized using IR light of the Free Electron Laser for Intra-Cavity Experiments (FELICE). We observed the formation of PtCH2+, Pt(ethene)+, and Pt(ethene)2+. These findings demonstrate the C−H bond activation and C−C coupling of methane molecules.
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影响因子：
3.4
作者：
Armentrout, P. B.;Parke, Laura;Citir, Murat
通讯作者：
Citir, Murat
影响因子：
15
作者：
IRIKURA, KK;BEAUCHAMP, JL
通讯作者：
BEAUCHAMP, JL
影响因子：
2.9
作者：
Pavlov, M;Blomberg, MRA;Schwarz, H
通讯作者：
Schwarz, H
影响因子：
4.4
作者：
BECKE, AD
通讯作者：
BECKE, AD
DOI：
10.1007/s13361-018-1929-7
发表时间：
2018-09-01
影响因子：
3.2
作者：
Armentrout, P. B.;Kuijpers, Stach E. J.;Bakker, Joost M.
通讯作者：
Bakker, Joost M.