Stepwise Functionalization of N-2 at Mo: Nitrido to Imido to Amido - Factors Favoring Amine Elimination from the Amido Complex

Functionalization of nitrido complex [((PP2Cy)-P-Ph)Mo(N)(I)] by a bis-silane in concentrated medium generates the hydrido-imido complex [((PP2Cy)-P-Ph)Mo(H)(=NSiMe2CH2CH2SiMe2H)(I)]. Abstraction of the iodide by thallium salt TlX (X = PF6, OTf) results in a second N-Si bond formation and forms the bis-hydride amide complex [((PP2Cy)-P-Ph)Mo(H)(2)(NSiMe2CH2CH2SiMe2)](+). An alternative synthesis relies on the abstraction of the iodide from the nitride complex [((PP2Cy)-P-Ph)Mo(N)(I)] to generate the corresponding cationic complex [((PP2Cy)-P-Ph)Mo(N)](+) followed by addition of the bis-silane. Addition of PMe3 to the [((PP2Cy)-P-Ph)Mo(H)(2)(NSiMe2CH2CH2SiMe2)](+) complex liberates the silylamine and forms the Mo-(II) cationic complex [((PP2Cy)-P-Ph)Mo(H)(PMe3)](+). DFT calculations rationalizing the observed reactivity are presented.