A Four Coordinated Iron(II)-Digermyl Complex as an Effective Precursor for the Catalytic Dehydrogenation of Ammonia Borane

Abstract

A coordinatively unsaturated iron(II)-digermyl complex, Fe[Ge(SiMe3)3]2(THF)2 (1), was synthesized in one step by the reaction of FeBr2 with 2 equiv of KGe(SiMe3)3. Complex 1 shows catalytic activity comparable to that of its silicon analogue in reduction reactions. In addition, 1 acts as an effective precursor for the catalytic dehydrogenation of ammonia borane. Catalytically active species can also be generated in situ by simple mixing of the easy-to-handle precursors FeBr2, Ge(SiMe3)4, KOtBu, and phenanthroline.

Germanium hydrides as an efficient hydrogen-storage material operated by an iron catalyst

“…The Fe–Ge bond distances in 3 (2.5712(6)/2.5557(5) Å) are elongated compared to those in 2 and other previously reported iron( ii ) germyl complexes, 12–14 although they are comparable to that of our previously reported iron( ii ) digermyl complex with a tetrahedral coordination geometry, (THF) 2 Fe[Ge(SiMe 3 ) 3 ] 2 (2.5589(8) Å). 15 The iron center and three germanium atoms form a nearly planar metallacyclic skeleton, wherein the deviation of all atoms from the least-squares plane ranges from 0.116 Å to 0.124 Å. It is worth noting here that the Ge–Ge-bond-forming reaction apparently occurs during the reaction of 2 with Ph 2 GeH 2 to produce 3 .…”

Editorial: Special Issue on “Advanced Strategies for Catalyst Design”

“…Kobayashi and Sunada have described the synthesis of a four coordinated Fe(II) digermyl complex, inspired by the silicon analog, which is used as catalyst in the dehydrogenation of ammonia borane [3].…”

“…In the former, the asymmetric cyanation of olefins with ethyl cyanoformate catalyzed by Ti(IV) has been explored, while in the latter, the acetylene [2+2+2] cycloaddition to benzene catalyzed by Rh/Cr indenyl fragments has been investigated. The accurate description of the reaction mechanisms combined with the activation strain model nicely Kobayashi and Sunada have described the synthesis of a four coordinated Fe(II) digermyl complex, inspired by the silicon analog, which is used as catalyst in the dehydrogenation of ammonia borane [3].…”