Cho Han-Gook, Andrews Lester
Department of Chemistry, Incheon National University , 119 Academy-ro, Yeonsu-gu, Incheon 22012, South Korea.
Department of Chemistry, University of Virginia , P.O. Box 400319, Charlottesville, Virginia 22904-4319, United States.
J Phys Chem A. 2017 Sep 14;121(36):6766-6777. doi: 10.1021/acs.jpca.7b06571. Epub 2017 Aug 31.
The primary products in reactions of laser-ablated group 5 metal atoms with ethane were identified in argon matrix IR spectra and characterized via density functional theory computations. The second- and third-row transition metals Nb and Ta produced insertion, metallacyclopropane, vinyl trihydrido, and anionic ethylidyne complexes (CHCH-MH, (CH)-MH, CH═CH-MH, and CHC≡MH), while the first-row transition metal V yielded only the insertion and metallacyclopropane products. The energetically higher ethylidenes and neutral ethylidynes (CHCH═MH and CHC[Formula: see text]MH) were not detected. The unique anionic ethylidynes are the most stable anionic species in the Nb and Ta systems. Evidently back-donation from the metal center to the C-C π* orbital is stronger than that in the group 6 metal analogue but weaker than that in the corresponding group 4 metal complex. The C-M bond for the Nb and Ta ethylidyne anions is a true triple bond.
在氩气基质红外光谱中鉴定了激光烧蚀的第5族金属原子与乙烷反应的主要产物，并通过密度泛函理论计算对其进行了表征。第二和第三周期过渡金属铌（Nb）和钽（Ta）生成了插入产物、金属环丙烷、乙烯基三氢化物和阴离子乙炔基配合物（CHCH-MH、(CH)-MH、CH═CH-MH和CHC≡MH），而第一周期过渡金属钒（V）仅生成了插入产物和金属环丙烷产物。能量较高的亚乙基和中性乙炔基（CHCH═MH和CHC[化学式：见原文]MH）未被检测到。独特的阴离子乙炔基是铌和钽体系中最稳定的阴离子物种。显然，从金属中心到C-C π*轨道的反馈π键作用比第6族金属类似物中的更强，但比相应的第4族金属配合物中的更弱。铌和钽乙炔基阴离子的C-M键是真正的三键。
