Silylene Extrusion from Organosilanes via Double Geminal Si−H Bond Activation by a Cp*Ru(κ²-<i>P</i>,<i>N</i>)⁺ Complex: Observation of a Key Stoichiometric Step in the Glaser−Tilley Alkene Hydrosilylation Mechanism

Treatment of Cp*RuCl(κ2-P,N-2b) (2b = 2-NMe2-3-PiPr2-indene) with TlSO3CF3 produced the cyclometalated complex [4]+SO3CF3- in 94% isolated yield. Exposure of [4]+X- (X = B(C6F5)4 or SO3CF3) to Ph2SiH2 (10 equiv) or PhSiH3 afforded the corresponding [Cp*(μ-P,N-2b)(H)2RuSiRPh]+X- complexes, [5]+X- (R = Ph; X = B(C6F5)4, 82%; X = SO3CF3, 39%) and [6]+X- (R = H; X = B(C6F5)4, 94%; X = SO3CF3, 95%). Notably, these transformations represent the first documented examples of Ru-mediated silylene extrusion via double geminal Si−H bond activation of an organosilanea key step in the recently proposed Glaser−Tilley (G−T) alkene hydrosilylation mechanism. Treatment of [5]+B(C6F5)4- with KN(SiMe3)2 or [6]+SO3CF3- with NaN(SiMe3)2 afforded the corresponding zwitterionic Cp*(μ-2-NMe2-3-PiPr2-indenide)(H)2RuSiRPh complex in 69% (R = Ph, 7) or 86% (R = H, 8) isolated yield. Both [6]+X- and 8 proved unreactive toward 1-hexene and styrene and provided negligible catalytic turnover in the attempted metal-mediated hydrosilylation of these substrates with PhSiH3, thereby providing further empirical evidence for the required intermediacy of base-free RuSi species in the G−T mechanism. Isomerization of the P,N-indene ligand backbone in [6]+X-, giving rise to [Cp*(μ-1-PiPr2-2-NMe2-indene)(H)2RuSiHPh]+X- ([9]+X-), was observed. In the case of [9]+SO3CF3-, net intramolecular addition of the RuSi−H group across the styrene-like CC unit within the ligand backbone to give 10 (96% isolated yield) was observed. Crystallographic characterization data are provided for [4]+X-, [5]+X-, [6]+X-, 8, and 10.将五甲基环戊二烯基氯化钌(κ2-P,N-2b)（Cp*RuCl(κ2-P,N-2b)，其中2b=2-二甲氨基-3-二异丙基膦基茚）与三氟甲磺酸铊（TlSO3CF3）反应，以94%的分离产率得到环金属化配合物[4]+SO3CF3-。将[4]+X-（X=四(五氟苯基)硼酸根B(C6F5)4或三氟甲磺酸根SO3CF3-）与10当量的二苯基硅烷（Ph2SiH2）或苯基硅烷（PhSiH3）反应，可得到相应的[Cp*(μ-P,N-2b)(H)2Ru=SiRPh]+X-型配合物：当R=Ph、X=B(C6F5)4时为[5]+X-（产率82%），X=SO3CF3-时产率39%；当R=H时为[6]+X-（X=B(C6F5)4时产率94%，X=SO3CF3-时产率95%）。值得注意的是，这些转化是首例被报道的通过有机硅烷偕位Si-H键双重活化实现钌介导的硅烯挤出反应——这是近期提出的格拉泽-蒂利（Glaser-Tilley, G-T）烯烃氢硅化反应机理中的关键步骤。用六甲基二硅基氨基钾（KN(SiMe3)2）处理[5]+B(C6F5)4-，或用六甲基二硅基氨基钠（NaN(SiMe3)2）处理[6]+SO3CF3-，可得到相应的两性离子型Cp*(μ-2-二甲氨基-3-二异丙基膦基茚负离子)(H)2Ru=SiRPh配合物，其中R=Ph时为7（产率69%），R=H时为8（产率86%），均为分离产率。[6]+X-和8均不与1-己烯、苯乙烯发生反应，且在尝试以PhSiH3为硅源对上述底物进行金属介导的氢硅化反应时，仅表现出可忽略的催化周转数，这为G-T机理中无碱Ru=Si物种作为必需中间体提供了进一步的实验证据。观察到[6]+X-中的P,N-茚配体骨架发生异构化，生成[Cp*(μ-1-二异丙基膦基-2-二甲氨基茚)(H)2Ru=SiHPh]+X-（即[9]+X-）。对于[9]+SO3CF3-，可发生配体骨架内类苯乙烯C=C单元与Ru=Si-H基团的净分子内加成反应，得到产物10（分离产率96%）。本文提供了[4]+X-、[5]+X-、[6]+X-、8和10的晶体结构表征数据。