Synthesis and Characterization of Bioinspired [Mo₂Fe₂]–Hydride Cluster Complexes and Their Application in the Catalytic Silylation of N₂

Abstract

The hydride-supported [Mo Fe ] cluster complex {Cp*Mo(PMe )} {FeN(SiMe ) } (H) (2 a; Cp*=η -C Me ) and its [Mo Mn ] congener 2 b were synthesized from the reactions of Cp*Mo(PMe )(H) (1) with M{N(SiMe ) } (M=Fe, Mn). The amide-to-thiolate ligand-exchange reactions of complex 2 a with bulky thiol reagents (HSR; R=2,4,6-iPr C H (Tip), 2,6-(SiMe ) C H (Btp)) furnished the corresponding hydride-supported [Mo Fe ](SR) cluster complexes. The [Mo Fe ] clusters served as catalyst precursors for the reductive silylation of N and yielded ≈65-69 equivalents of N(SiMe ) relative to the [Mo Fe ] clusters. Treatment of complexes 2 a and b with an excess of CNtBu resulted in the formation of dinuclear Mo-Fe and Mo-Mn complexes, which indicated that the [Mo M ] cores (M=Fe, Mn) split into two dinuclear species upon accommodation of substrates.

Catalytic Silylation of Dinitrogen by a Family of Triiron Complexes

“…This improvement using Et 2 O can be rationalized as a combination of possible factors, such as an increased solubility of N 2 in Et 2 O and solubility differences for triiron intermediates. 31–33 Whereas the yields obtained in the 9:1 Et 2 O:PhMe mixture are comparable to other iron-based catalysts for this reaction under ambient conditions, 11,27,29,30,34–36 the yield based on KC 8 – that is, the efficiency with which reducing equivalents are converted into N(SiMe 3 ) 3 – is the highest of any reported system (Table S2). Lowering the reaction temperature to −34 °C results in only 33 ± 3 equiv.…”

Dinitrogen Fixation: Rationalizing Strategies Utilizing Molecular Complexes

“…This is closely related to the mechanism of the nitrogenase cofactor, as evidence for ligand dissociation to generate active sites was probed recently [8] . The same group took a step further by synthesizing the heteropolymetallic molybdenum‐iron and molybdenum‐manganese hydride clusters 295 – 298 (Scheme 58 b), which were all shown to catalytically convert N 2 to N(SiMe 3 ) 3 in the presence of Me 3 SiCl and metallic sodium as a reducing agent [237] . The iron and manganese clusters 295 and 296 could, respectively afford 69 and 12 equiv of N(SiMe 3 ) 3 per equiv of cluster.…”

Ammonia Formation Catalyzed by a Dinitrogen‐Bridged Dirhenium Complex Bearing PNP‐Pincer Ligands under Mild Reaction Conditions**

“…[3][4][5][6][7][8] Furthermore, the catalytic reduction of dinitrogen into silylamines was achieved using Ti-, V-, Cr-, Mo-, W-, Mn-, Fe-, Co-, Rh-, Ni-, and U-complexes as catalysts. [9][10][11][12][13][14][15][16][17] During the last decade, substantial progress has been made in the study on the preparation and reactivity of rhenium-dinitrogen complexes. [18][19][20][21] The typical examples are as follows.…”