Höllerhage Thomas, Spaniol Thomas P, Carpentier Ambre, Maron Laurent, Okuda Jun
Institute of Inorganic Chemistry, RWTH Aachen University, Landoltweg 1, 52056 Aachen, Germany.
CNRS, INSA, UPS, UMR 5215, LPCNO, Université de Toulouse 135, avenue de Rangueil, 31077 Toulouse, France.
Inorg Chem. 2022 Feb 21;61(7):3309-3316. doi: 10.1021/acs.inorgchem.1c03894. Epub 2022 Feb 9.
The use of the 15-membered NNNNN macrocyclic ligand MePACP (MePACP = 1,4,7,10,13-pentamethyl-1,4,7,10,13-pentaazacyclopentadecane) allowed the isolation of two cationic strontium hydride complexes by hydrogenolysis of benzyl precursors. Treatment of sparingly soluble [(MePACP)Sr(CHPh)] with dihydrogen gave free MePACP, toluene, and oligomeric strontium hydride [SrH], while hydrogenolysis in the presence of 1 equiv of the benzyl cation [(MePACP)Sr(CHPh)][B(CH-3,5-Me)] enabled isolation of the thermally unstable trihydride cation [(MePACP)Sr(μ-H)][B(CH-3,5-Me)]. When the benzyl cation [(MePACP)Sr(CHPh)][BAr] (Ar = CH-3,5-Me or CH-4-Bu) was reacted with dihydrogen or -octylsilane, dihydride complexes [(MePACP)Sr(μ-H)][BAr] containing a dinuclear core bridged by two hydride ligands were obtained. The soluble dihydride complex [(MePACP)Sr(μ-H)][B(CH-4-Bu)] was tested in olefin hydrogenation and hydrosilylation catalysis. Kinetic analyses for [(MePACP)Sr(μ-H)] showed lower catalytic activity as compared to that of the isostructural calcium homologue [(MePACP)Ca(μ-H)]. This is explained by a shift in the monomer-dimer equilibrium which precedes the catalytic cycle.
使用含有15个氮原子的大环配体MePACP（MePACP = 1,4,7,10,13 - 五甲基 - 1,4,7,10,13 - 五氮杂环十五烷），通过苄基前体的氢解反应分离得到了两种阳离子氢化锶配合物。用氢气处理微溶的[(MePACP)Sr(CHPh)]，得到游离的MePACP、甲苯和低聚氢化锶[SrH]，而在1当量苄基阳离子[(MePACP)Sr(CHPh)][B(CH₃,₅ - Me)]存在下进行氢解反应，能够分离得到热不稳定的三氢化物阳离子[(MePACP)Sr(μ - H)][B(CH₃,₅ - Me)]。当苄基阳离子[(MePACP)Sr(CHPh)][BAr]（Ar = CH₃,₅ - Me或CH₄ - Bu）与氢气或正辛基硅烷反应时，得到了含有由两个氢化物配体桥连的双核核心的二氢化物配合物[(MePACP)Sr(μ - H)][BAr]。对可溶性二氢化物配合物[(MePACP)Sr(μ - H)][B(CH₄ - Bu)]进行了烯烃氢化和硅氢化催化测试。[(MePACP)Sr(μ - H)]的动力学分析表明，与同结构的钙类似物[(MePACP)Ca(μ - H)]相比，其催化活性较低。这可以通过催化循环之前单体 - 二聚体平衡的移动来解释。
