Iron(I) and Iron(II) Amido-imidazolin-2-imine Complexes as Catalysts for H/D Exchange in Hydrosilanes
Noor U Din Reshi, Dirk Bockfeld, Dirk Baabe, Lars Denker, Juan Pablo Martínez, Bartosz Trzaskowski, René Frank, Matthias Tamm
Abstract
High Resolution Image Download MS PowerPoint Slide The unsymmetrical amino-imidazolin-2-imine ligand [HAmIm, 1,2-(DippNH)–C 6 H 4 –N=C(N i PrCMe) 2 ] is employed in the synthesis of the iron(I) arene complex [(AmIm)Fe( η 6 -C 6 H 6 )] and the iron(II) neosilyl complex [(AmIm)Fe(CH 2 SiMe 3 )]. These compounds are highly efficient precatalysts in H/D exchange reactions with deuterium (D 2 ) in hydrosilanes. The scope comprises primary to tertiary silanes at a catalyst loading of 1 mol % at ambient temperature. In-depth mechanistic studies including various control experiments and the syntheses of isolated iron-hydride and iron-silyl compounds are performed. These studies reveal that the activation of both Fe(I) and Fe(II) complexes generates Fe–H/D species as key catalytic intermediates. An alternative catalytic pathway involving an iron-silyl intermediate, although shown to be less feasible by DFT calculations, may also be operative.