Preparation and Molecular and Electronic Structures of Iron(0)
Dinitrogen and Silane Complexes and Their Application to
Catalytic Hydrogenation and Hydrosilation
posted on 2004-10-27, 00:00authored bySuzanne C. Bart, Emil Lobkovsky, Paul J. Chirik
Reduction of the five-coordinate iron(II) dihalide complexes (iPrPDI)FeX2 (iPrPDI = ((2,6-CHMe2)2C6H3NCMe)2C5H3N; X = Cl, Br) with sodium amalgam under 1 atm of dinitrogen afforded the
square pyramidal, high spin iron(0) bis(dinitrogen) complex (iPrPDI)Fe(N2)2. In solution, (iPrPDI)Fe(N2)2 loses
1 equiv of N2 to afford the mono(dinitrogen) adduct (iPrPDI)Fe(N2). Both dinitrogen compounds serve as
effective precatalysts for the hydrogenation and hydrosilation of olefins and alkynes. Effecient catalytic
reactions are observed with low catalyst loadings (≤0.3 mol %) at ambient temperature in nonpolar media.
The catalytic hydrosilations are selective in forming the anti-Markovnikov product. Structural characterization
of a high spin iron(0) alkyne and a bis(silane) σ-complex has also been accomplished and in combination
with isotopic labeling studies provides insight into the mechanism of both catalytic C−H and catalytic C−Si
bond formation.