Double α,α CH bond insertion into sp3 CH2 moiety: synthesis of a Fe carbene bis-hydride dinitrogen complex

Abstract

Reduction of high spin paramagnetic complex [(κ²-P, P′-PCH₂P^Cy)FeCl₂] 2 by two electrons under N₂ resulted in the formation of two isomeric low spin diamagnetic complexes 3trans and 3cis [Fe(κ³-P,C,P′-PCP^Cy)(H)₂(N₂)]. Cristallization allowed isolation of complex 3d [Fe(κ³-P,C,P′-PCP^Cy)(H)₂]₂(μ-N₂), characterized by X-ray diffraction, Mössbauer and Raman spectroscopies. DFT calculations rationalized the facile double α,α CH bond insertion into a single sp³ CH₂ moiety, as well as the fast exchange positions of the hydrides in the cis dihydride complex observed by NMR spectrocscopy.