Marks Joshua H, Ward Timothy B, Brathwaite Antonio D, Ferguson Sojourna, Duncan Michael A
Department of Chemistry , University of Georgia , Athens , Georgia 30602 , United States.
Department of Chemistry , Emory University , Atlanta , Georgia 30322 , United States.
J Phys Chem A. 2019 Aug 8;123(31):6733-6743. doi: 10.1021/acs.jpca.9b04962. Epub 2019 Jul 25.
Infrared laser spectroscopy and mass spectrometry were used to determine the structures of intermediates and products in the single-atom-catalyzed trimerization of acetylene to form benzene. Complexes of the form V(CH) were produced in the gas phase via laser ablation in a pulsed-nozzle source, size-selected with a mass spectrometer, and studied with infrared laser photodissociation spectroscopy. Density functional theory calculations were performed in support of the experiments. Single- and double-acetylene complexes form V(CH) metallacycle structures. Three-acetylene complexes exhibit a surprising dependence on the acetylene concentration, forming V(CH) and (CH)V(CH) tri- and dimetallacycle ion structures at low concentrations and eventually V(benzene) at higher concentrations. These observations reveal intermediates along the reaction path of acetylene cyclotrimerization to benzene.
利用红外激光光谱和质谱来确定单原子催化乙炔三聚生成苯过程中的中间体和产物的结构。通过在脉冲喷嘴源中进行激光烧蚀，在气相中生成了V(CH)形式的配合物，用质谱仪进行尺寸选择，并通过红外激光光解离光谱进行研究。进行了密度泛函理论计算以支持实验。单乙炔和双乙炔配合物形成V(CH)金属环结构。三乙炔配合物对乙炔浓度表现出惊人的依赖性，在低浓度下形成V(CH)和(CH)V(CH)三金属环和双金属环离子结构，在较高浓度下最终形成V(苯)。这些观察结果揭示了乙炔环三聚生成苯反应路径上的中间体。
