1586-73-8Relevant articles and documents
[Fe4] and [Fe6] Hydride Clusters Supported by Phosphines: Synthesis, Characterization, and Application in N2 Reduction
Araake, Ryoichi,Sakadani, Kazuki,Tada, Mizuki,Sakai, Yoichi,Ohki, Yasuhiro
, p. 5596 - 5606 (2017)
Multiple iron atoms bridged by hydrides is a common structural feature of the active species that have been postulated in the biological and industrial reduction of N2. In this study, the reactions of an Fe(II) amide complex with pinacolborane in the presence/absence of phosphines afforded a series of hydride-supported [Fe4] and [Fe6] clusters Fe4(μ-H)4(μ3-H)2{N(SiMe3)2}2(PR3)4 (PR3 = PMe3 (2a), PMe2Ph (2b), PEt3 (2c)), Fe6(μ-H)10(μ3-H)2(PMe3)10 (3), and (η6-C7H8)Fe4(μ-H)2{μ-N(SiMe3)2}2{N(SiMe3)2}2 (4), which were characterized crystallographically and spectroscopically. Under ambient conditions, these clusters catalyzed the silylation of N2 to furnish up to 160 ± 13 equiv of N(SiMe3)3 per 2c (40 equiv per Fe atom) and 183 ± 18 equiv per 3 (31 equiv per Fe atom). With regard to the generation of the reactive species, dissociation of phosphine and hydride ligands from the [Fe4] and [Fe6] clusters was indicated, based on the results of the mass spectrometric analysis on the [Fe6] cluster, as well as the formation of a diphenylsilane adduct of the [Fe4] cluster.
Synthesis and Characterization of Bioinspired [Mo2Fe2]–Hydride Cluster Complexes and Their Application in the Catalytic Silylation of N2
Ohki, Yasuhiro,Araki, Yuna,Tada, Mizuki,Sakai, Yoichi
, p. 13240 - 13248 (2017)
The hydride-supported [Mo2Fe2] cluster complex {Cp*Mo(PMe3)}2{FeN(SiMe3)2}2(H)8 (2 a; Cp=η5-C5Me5) and its [Mo2Mn2] congener 2 b were synthesized from the reactions of Cp*Mo(PMe3)(H)5 (1) with M{N(SiMe3)2}2 (M=Fe, Mn). The amide-to-thiolate ligand-exchange reactions of complex 2 a with bulky thiol reagents (HSR; R=2,4,6-iPr3C6H2 (Tip), 2,6-(SiMe3)2C6H3 (Btp)) furnished the corresponding hydride-supported [Mo2Fe2](SR)2 cluster complexes. The [Mo2Fe2] clusters served as catalyst precursors for the reductive silylation of N2 and yielded ≈65–69 equivalents of N(SiMe3)3 relative to the [Mo2Fe2] 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 [Mo2M2] cores (M=Fe, Mn) split into two dinuclear species upon accommodation of substrates.
Conversion of dinitrogen to tris(trimethylsilyl)amine catalyzed by titanium triamido-amine complexes
Ghana, Priyabrata,Van Krüchten, Franziska D.,Spaniol, Thomas P.,Van Leusen, Jan,K?gerler, Paul,Okuda, Jun
, p. 3231 - 3234 (2019)
By using a triaryl-Tren ligated titanium dinitrogen complex, K2[{(Xy-N3N)Ti}2(μ2-N2)] (3), prepared by two-electron reduction of [TiCl(Xy-N3N)] (1-Cl) under N2 atmosphere, catalytic fixation of molecular nitrogen to form tris(trimethylsilyl)amine was achieved under ambient conditions with a turnover number (TON) of up to 16.5 per titanium atom.
Evaluating Metal Ion Identity on Catalytic Silylation of Dinitrogen Using a Series of Trimetallic Complexes
Eaton, Mary C.,Knight, Brian J.,Catalano, Vincent J.,Murray, Leslie J.
, p. 1519 - 1524 (2020)
We report catalytic silylation of dinitrogen to tris(trimethylsilyl)amine by a series of trinuclear first row transition metal complexes (M = Cr, Mn, Fe, Co, Ni) housed in our tris(β-diketiminate) cyclophane (L3–). Yields are expectedly dependent on metal ion type ranging from 14 to 199 equiv. NH4 +/complex after protonolysis for the Mn to Co congeners, respectively. For the series of complexes, the observed trend for the number of turnovers as a function of metal ion type is Co > Fe > Cr > Ni > Mn, consistent with prior reports of greater efficacy of Co over Fe in other ligand systems for this reaction.
Synthesis of Dinuclear Mo?Fe Hydride Complexes and Catalytic Silylation of N2
Ishihara, Kodai,Araki, Yuna,Tada, Mizuki,Takayama, Tsutomu,Sakai, Yoichi,Sameera,Ohki, Yasuhiro
, p. 9537 - 9546 (2020)
Two transition-metal atoms bridged by hydrides may represent a useful structural motif for N2 activation by molecular complexes and the enzyme active site. In this study, dinuclear MoIV-FeII complexes with bridging hydrides, CpRMo(PMe3)(H)(μ-H)3FeCp* (2 a; CpR=Cp=C5Me5, 2 b; CpR=C5Me4H), were synthesized via deprotonation of CpRMo(PMe3)H5 (1 a; CpR=Cp*, 1 b; CpR=C5Me4H) by Cp*FeN(SiMe3)2, and they were characterized by spectroscopy and crystallography. These Mo?Fe complexes reveal the shortest Mo?Fe distances ever reported (2.4005(3) ? for 2 a and 2.3952(3) ? for 2 b), and the Mo?Fe interactions were analyzed by computational studies. Removal of the terminal Mo?H hydride in 2 a–2 b by [Ph3C]+ in THF led to the formation of cationic THF adducts [CpRMo(PMe3)(THF)(μ-H)3FeCp*]+ (3 a; CpR=Cp*, 3 b; CpR=C5Me4H). Further reaction of 3 a with LiPPh2 gave rise to a phosphido-bridged complex Cp*Mo(PMe3)(μ-H)(μ-PPh2)FeCp* (4). A series of Mo?Fe complexes were subjected to catalytic silylation of N2 in the presence of Na and Me3SiCl, furnishing up to 129±20 equiv of N(SiMe3)3 per molecule of 2 b. Mechanism of the catalytic cycle was analyzed by DFT calculations.
N2 Silylation Catalyzed by a Bis(silylene)-Based [SiCSi] Pincer Hydrido Iron(II) Dinitrogen Complex
Li, Shengyong,Wang, Yajie,Yang, Wenjing,Li, Kai,Sun, Hongjian,Li, Xiaoyan,Fuhr, Olaf,Fenske, Dieter
, p. 757 - 766 (2020)
The bis(silylene)-based SiC(sp3)Si pincer ligand N,N′-bis(LSi:)dipyrromethane [SiCH2Si] (L1; L = PhC(NtBu)2) with a C(sp3) atom anchor was synthesized, and its coordination chemistry to iron was studied. Two novel iron hydride complexes, [SiCHSi]Fe(H)(N2)(PMe3) (1) and [SiCHSi]Fe(H)(PMe3)2 (2), were synthesized in the reaction of L1 with Fe(PMe3)4 via C(sp3)-H bond activation under different inert atmospheres (N2 and argon). To the best of our knowledge, 1 and 2 are the first examples of a bis(silylene)-based hydrido pincer iron complex produced through activation of a C(sp3)-H bond. At the same time 1 is also the first example of a TM dinitrogen complex supported by a bis(silylene) ligand. The interconversion between 1 and 2 was achieved and monitored by operando IR and 31P NMR spectra to understand the transformation from 1 to 2 from the viewpoint of kinetics. To our delight, 1 could effectively catalyze silylation of dinitrogen and gave the highest turnover number so far among all the Fe-catalyzed N2 silylation systems at room temperature and under atmospheric dinitrogen.
Merging Pincer Motifs and Potential Metal–Metal Cooperativity in Cobalt Dinitrogen Chemistry: Efficient Catalytic Silylation of N2 to N(SiMe3)3
Dechert, Sebastian,Demeshko, Serhiy,Gupta, Sandeep K.,Li, Ming,Meyer, Franc
, p. 14480 - 14487 (2021)
Using a pyrazolate-bridged dinucleating ligand that provides two proximate pincer-type PNN binding sites (“two-in-one pincer”), different synthetic routes have been developed towards its dicobalt(I) complex 2 that features a twice deprotonated ligand backbone and two weakly activated terminal N2 substrate ligands directed into the bimetallic pocket. Protonation of 2 is shown to occur at the ligand scaffold and to trigger conversion to a tetracobalt(I) complex 4 with two end-on μ1,2-bridging N2; in THF 4 is labile and undergoes temperature-dependent N2/triflate ligand exchange. These pyrazolate-based systems combine the potential of exhibiting both metal–metal and metal–ligand cooperativity, viz. two concepts that have emerged as promising design motifs for molecular N2 fixation catalysts. Complex 2 serves as an efficient (pre)catalyst for the reductive silylation of N2 into N(SiMe3)3 (using KC8 and Me3SiCl), yielding up to 240 equiv N(SiMe3)3 per catalyst.
N-Substituted hexamethyldisilazanes as new substances for the synthesis of functional films in the system Si-Ge-C-N-H
Sysoev,Nikulina,Kolontaeva,Kosinova,Titov,Rakhlin,Tsyrendorzhieva,Lis,Voronkov
, p. 2501 - 2505 (2011)
N-Organylbis(trimethylsilyl)amines of the general formula RN(SiMe 3)2 (R = Me3Si, Et3Ge) were synthesized by reaction of sodium bis(trimethylsilyl)amide with the corresponding trialkylsilyl(germyl) halide. Their IR, UV, and 1H, 13C, and 29Si NMR spectra were studied, and saturated vapor pressures and thermal stabilities were determined. The possibility of using the RN(SiMe3)2 compounds as precursors in chemical vapor deposition of films with specified composition was estimated by thermodynamic modeling. Pleiades Publishing, Ltd., 2011.
Synthesis and Reactivity of Iron– and Cobalt–Dinitrogen Complexes Bearing PSiP-Type Pincer Ligands toward Nitrogen Fixation
Imayoshi, Ryuji,Nakajima, Kazunari,Takaya, Jun,Iwasawa, Nobuharu,Nishibayashi, Yoshiaki
, p. 3769 - 3778 (2017)
Iron– and cobalt–dinitrogen complexes bearing PSiP-type pincer ligands are newly designed and prepared, on the basis of our previous proposal that iron– and cobalt–dinitrogen complexes bearing trimethylsilyl ligands are key reactive intermediates in the c
New P-S-N containing ring systems. Reaction of 2,4-(naphthalene-1,8-diyl)-1,3,2,4-dithiadiphosphetane 2,4-disulfide and its 4-methoxynaphthalene derivative with hexamethyldisilazane
Kilian, Petr,Marek, Jaromir,Marek, Radek,Tou-In, Jioi,Humpa, Otakar,Novosad, Josef,Woollins, J. Derek
, p. 1175 - 1180 (1998)
Reaction of 2,4-(naphthalene-1,8-diyl)-1,3,2,4-dithiadiphosphetane 2,4-disulfide 1 with hexamethyldisilazane (hmds) in acetonitrile gave the N,N′-bis(trimethylsilyl)acetamidinium salt of the [(C10H6)P(S)(NHSiMe3)SP(S)2] - anion 2, a product of P2S2 ring cleavage, together with the new thiazaphosphetidine (C10H6)P(S)SN(SiMe3)P(S) 3. Analogous (methoxy derived) products to 2 (2a, 2b) and 3 (3a) were obtained when 2,4-(4-methoxynaphthalene-1,8-diyl)-1,3,2,4-dithiadiphosphetane 2,4-disulfide 1a was used instead of 1. When the reaction of 1 with hmds was performed in dichloromethane a mixture of the products was obtained, from which the hexamethyldisilazan-2-ium salt of the anion of identical structure to that in 2 has been isolated. No reaction occurred when a solventless system was used. The new compounds were studied spectroscopically (one- and two-dimensional NMR, IR spectroscopy) and by X-ray crystallography (3, 3a and 4).
