N‐nacnac stabilized tetrylenes: access to silicon hydride systems via migration processes

The use of an amino‐functionalized β‐diketiminate (′N‐nacnac′) ligand in low‐valent silicon chemistry is investigated. In particular, the use of ( L Dipp )SiCl ( L Dipp =HC{(Me 2 N)CNDipp} 2 ) to generate silicon‐containing products via metathesis chemistry is explored, in light of previously reported complications arising from heterocycle ring contraction. In the case of Na[C 5 H 5 ], chloride metathesis is accompanied not by rearrangement of the N‐nacnac ligand, but by a C‐to‐Si hydrogen migration process, generating the hydridosilicon(IV) species ( L Dipp )Si(H)(C 5 H 4 ), which features a silafulvene core. The potential intermediate arising from initial chloride/cyclopentadienide substitution can be modelled by the chemistry of the corresponding Ge(II) and Sn(II) systems, which generate ( L Dipp )E(η 1 −C 5 H 5 ) (E=Ge, Sn) via straightforward metathesis chemistry. A Si(II) hydride species can be generated from ( L Dipp )SiCl via metathesis by making use of a d‐block reagent which can act as both hydride source and coordinative trap for ( L Dipp )SiH. Thus, the reaction of ( L Dipp )SiCl with K[(η 5 −C 5 H 4 Me)Mn(CO) 2 H] leads to the formation of (η 5 −C 5 H 4 Me)Mn(CO) 2 {Si(H) L Dipp } – the first silylene complex containing this half‐sandwich manganese fragment.