Cationic and Neutral Cp*M(NO)(κ<sup>2</sup>‑Ph<sub>2</sub>PCH<sub>2</sub>CH<sub>2</sub>PPh<sub>2</sub>) Complexes of Molybdenum and Tungsten: Lewis-Acid-Induced Intramolecular C–H Activation
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Treatment of CH2Cl2 solutions of Cp*M(NO)Cl2 (Cp* = η5-C5(CH3)5; M = Mo, W) first with 2 equiv of AgSbF6 in the presence of PhCN and then with 1 equiv of Ph2PCH2CH2PPh2 affords the yellow–orange salts [Cp*M(NO)(PhCN)(κ2-Ph2PCH2CH2PPh2)](SbF6)2 in good yields (M = Mo, W). Reduction of [Cp*M(NO)(PhCN)(κ2-Ph2PCH2CH2PPh2)](SbF6)2 with 2 equiv of Cp2Co in C6H6 at 80 °C produces the corresponding 18e neutral compounds, Cp*M(NO)(κ2-Ph2PCH2CH2PPh2) which have been isolated as analytically pure orange–red solids. The addition of 1 equiv of the Lewis acid, Sc(OTf)3, to solutions of Cp*M(NO)(κ2-Ph2PCH2CH2PPh2) at room temperature results in the immediate formation of thermally stable Cp*M(NO→Sc(OTf)3)(H)(κ3-(C6H4)PhPCH2CH2PPh2) complexes in which one of the phenyl substituents of the Ph2PCH2CH2PPh2 ligands has undergone intramolecular orthometalation. In a similar manner, addition of BF3 produces the analogous Cp*M(NO→BF3)(H)(κ3-(C6H4)PhPCH2CH2PPh2) complexes. In contrast, B(C6F5)3 forms the 1:1 Lewis acid–base adducts, Cp*M(NO→B(C6F5)3)(κ2-Ph2PCH2CH2PPh2) in CH2Cl2 at room temperature. Upon warming to 80 °C, Cp*Mo(NO→B(C6F5)3)(κ2-Ph2PCH2CH2PPh2) converts cleanly to the orthometalated product Cp*Mo(NO→B(C6F5)3)(H)(κ3-(C6H4)PhPCH2CH2PPh2), but Cp*W(NO→B(C6F5)3)(κ2-Ph2PCH2CH2PPh2) generates a mixture of products whose identities remain to be ascertained. Attempts to extend this chemistry to include related Ph2PCH2PPh2 compounds have had only limited success. All new complexes have been characterized by conventional spectroscopic and analytical methods, and the solid-state molecular structures of most of them have been established by single-crystal X-ray crystallographic analyses.
将Cp*M(NO)Cl₂（Cp* = η⁵-五甲基环戊二烯基，即η⁵-C₅(CH₃)₅；M = 钼（Mo）、钨（W））的二氯甲烷（CH₂Cl₂）溶液，先在苯甲腈（PhCN）存在下与2当量的六氟锑酸银（AgSbF₆）反应，再与1当量的1,2-双(二苯基膦基)乙烷（Ph₂PCH₂CH₂PPh₂）反应，以良好收率得到黄橙色盐类[Cp*M(NO)(PhCN)(κ²-Ph₂PCH₂CH₂PPh₂)](SbF₆)₂（M = Mo、W）。将[Cp*M(NO)(PhCN)(κ²-Ph₂PCH₂CH₂PPh₂)](SbF₆)₂与2当量的二茂钴（Cp₂Co）在苯（C₆H₆）中于80 ℃下还原，可得到相应的18电子中性化合物Cp*M(NO)(κ²-Ph₂PCH₂CH₂PPh₂)，该产物可分离为分析纯的橙红色固体。在室温下向Cp*M(NO)(κ²-Ph₂PCH₂CH₂PPh₂)的溶液中加入1当量路易斯酸三氟甲磺酸钪（Sc(OTf)₃），会立即生成热稳定的Cp*M(NO→Sc(OTf)₃)(H)(κ³-(C₆H₄)PhPCH₂CH₂PPh₂)配合物，其中1,2-双(二苯基膦基)乙烷配体的其中一个苯基取代基发生了分子内邻位金属化。以类似方式，加入三氟化硼（BF₃）可得到同类的Cp*M(NO→BF₃)(H)(κ³-(C₆H₄)PhPCH₂CH₂PPh₂)配合物。与之相反，三(五氟苯基)硼烷（B(C₆F₅)₃）在二氯甲烷（CH₂Cl₂）中于室温下可形成1:1的路易斯酸碱加合物Cp*M(NO→B(C₆F₅)₃)(κ²-Ph₂PCH₂CH₂PPh₂)。将Cp*Mo(NO→B(C₆F₅)₃)(κ²-Ph₂PCH₂CH₂PPh₂)升温至80 ℃时，可完全转化为邻位金属化产物Cp*Mo(NO→B(C₆F₅)₃)(H)(κ³-(C₆H₄)PhPCH₂CH₂PPh₂)；而Cp*W(NO→B(C₆F₅)₃)(κ²-Ph₂PCH₂CH₂PPh₂)则会生成产物混合物，其具体组成仍有待确定。尝试将该化学体系拓展至相关的双(二苯基膦基)甲烷（Ph₂PCH₂PPh₂）类化合物时，仅取得了有限的成果。所有新合成的配合物均通过常规光谱学与分析方法完成了表征，其中多数配合物的固态分子结构已通过单晶X射线衍射分析得以确定。
