Siloxide Podand Ligand as a Scaffold for Molybdenum-Catalyzed Alkyne Metathesis and Isolation of a Dynamic Metallatetrahedrane Intermediate

Triphenylsiloxide is one of the most successful ancillary ligands for Mo­(VI)-alkyne metathesis catalysts. It was proposed that flexible siloxide ligands allow Mo–O–Si bond angles to modulate the electrophilicity of MoC and thereby promote the catalysis. Introduction of a siloxide podand ligand allowed elucidation of the effect of ligand flexibility and Mo–O–Si angles on the electrophilicity of MoC. It also allowed for the isolation of a rare metallatetrahedrane of Mo­(VI) which was found to be dynamic in solution.三苯硅氧基（Triphenylsiloxide）是目前最为成功的钼(VI)基炔烃复分解催化剂的辅助配体之一。已有研究提出，柔性硅氧基配体可通过调节Mo-O-Si键角，调控Mo≡C键的亲电性，从而促进催化反应进行。引入硅氧基podand配体后，我们得以阐明配体柔性与Mo-O-Si键角对Mo≡C键亲电性的影响；同时还成功分离得到一种罕见的钼(VI)基金属四面体烷（metallatetrahedrane），该化合物在溶液中表现出动态特性。