Hydride transfer reactions in dimolybdenum compounds: a simple route to the novel μ-η1∶η1-tetrahydroboride complex [Mo2Cp2(μ-SMe)3(μ-BH4)]

Schollhammer, Philippe; Cabon, Nolwenn; Pétillon, François Y.; Talarmin, Jean; Muir, Kenneth W.

doi:10.1039/b006457m

Cited by 15 publications

(25 citation statements)

References 10 publications

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“…[64] The first reduction step (step B1) would be analogous to the reactions observed upon reduction of [Mo 2 Cp 2 (m-SMe) 3 (MeCN) 2 ] , that is transformation of one MeCN ligand from terminal to a m-h 1 -bridging azavinylidene, with elimination of the second MeCN ligand. [65] An alternative possibility for steps A and B is that N 2 binds to both metal centres in the Fryzuk mode [58] (step A2). The (2e, 1H ) reduction of a complex in which a vinylidene fragment is bound to the {[Mo 2 Cp 2 (mSMe) 3 ] } core in the m-h 1 :h 2 -mode produces a m-h 1 -carbyne derivative.…”

Section: Discussionmentioning

confidence: 99%

Electrochemical Cleavage of NdN Bonds at a Mo2(μ-SMe)3 Site Relevant to the Biological Reduction of Dinitrogen at a Bimetallic Sulfur Centre

et al. 2002

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Section: Discussionmentioning

confidence: 99%

Electrochemical Cleavage of NdN Bonds at a Mo2(μ-SMe)3 Site Relevant to the Biological Reduction of Dinitrogen at a Bimetallic Sulfur Centre

et al. 2002

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“…The characterisation of 8 was accomplished by NMR spectroscopy, which showed that it was identical to the tetrahydroboride [Mo 2 Cp 2 (-SMe) 3 (-BH 4 )] we had previously obtained in moderate yields, together with an azavinylidene product, from the reaction of [Mo 2 Cp 2 (-SMe) 3 (CH 3 CN) 2 ](BF 4 ) with NaBH 4 in either tetrahydrofuran or acetonitrile. 7 The synthesis of 8 from the metal chloride 1 is significantly more convenient than our previous method, which is based on the lability of CH 3 CN ligands.…”

Section: Reactions Of Dimolybdenum Complexes Withmentioning

confidence: 97%

“…The azavinylidene N1-C2 bond distance [1.234( 7) Å] accords with a bond order of two. 31 The closest structural comparison to 10 is provided by the quadruply-bridged Mo(III)-Mo(III) compound [Mo 2 Cp 2 (-SMe) 3 (-NC(H)Me)] (14), 7 which differs from 10 by having a -thiolato instead of a -phosphido ligand trans to the azavinylidene group. The mean Mo-N distances in 14 and 10 [2.078(8) and 2.116(3) Å] demonstrate yet again that phosphide exerts a high trans-influence (see sections 2.1.1 and 2.1.3 above).…”

Section: Reaction Of 2 Withmentioning

confidence: 99%

“…8)); competition between this reaction and formation of the azavinylidene 14 can be controlled by the solvent. 7 Here we describe the reaction of 8 with bases. Abstraction of BH 3 from 8 to give the hydrido compound [Mo 2 Cp 2 (-SMe) 3 (-H)] proved to be very difficult: the usual BH 3 abstractors failed to transform 8 into the corresponding hydride.…”

Section: Reactions Of 3 and 4 Withmentioning

confidence: 99%

“…1 In contrast, borohydride complexes [M(BH 4 )] of d-transition metals, with the exception of those of group 4, are less stable, decomposing readily to give either the corresponding hydride after elimination of borane 2,3 or a metallaborane after loss of dihydrogen. 3,4 Nevertheless, several stable borohydride complexes of d-transition elements have been isolated over the last fifteen years: examples are now known for the metals niobium, 5 chromium, 6 molybdenum, 7 manganese, 8 iron, 9 ruthenium, 10 osmium, 10b rhodium 11 and iridium. 12 The usual synthetic route to a borohydride complex involves reaction of a metal halide with an alkali-metal borohydride.…”

Section: Introductionmentioning

confidence: 99%

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Reaction of BH₄⁻with {Mo₂Cp₂(μ-SMe)_n} species to give tetrahydroborato, hydrido or dimetallaborane compounds: control of product by ancillary ligands

et al. 2004

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The reaction of mono- or dichloro-dimolybdenum(III) complexes [Mo2Cp2(mu-SMe)2(mu-Cl)(mu-Y)] (Cp=eta5-C5H5; 1, Y=SMe; 2, Y=PPh2; 3, Y=Cl) with NaBH4 at room temperature gave in high yields tetrahydroborato (8), hydrido (9) or metallaborane (12) complexes depending on the ancillary ligands. The correct formulation of derivatives and has been unambigously determined by X-ray diffraction methods. That of the hydrido compound 9 has been established in solution by NMR analysis and confirmed by an X-ray study of the mu-azavinylidene derivative [Mo2Cp2(mu-SMe)2(mu-PPh2)(mu-N=CHMe)] (10) obtained from the insertion of acetonitrile into the Mo-H bond of 9. Reaction of NaBH4 with nitrile derivatives, [Mo2Cp2(mu-SMe)4-n(CH3CN)2n]n+(5, n=1; 6 n=2), afforded the tetrahydroborato compound 8, together with a mu-azavinylidene species [Mo2Cp2(mu-SMe)3(mu-N=CHMe)](14), when n=1, and the metallaborane complex 12, together with a mixed borohydrato-azavinylidene derivative [Mo2Cp2(mu-SMe)2(mu-BH4)(mu-N=CHMe)] (13), when n=2. The molecular structures of these complexes have been confirmed by X-ray analysis. Preparations of some of the starting complexes (3 and 4) are also described, as are the molecular structures of the precursors [Mo2Cp2(mu-SMe)2(mu-X)(mu-Y)] (1, X/Y=Cl/SMe; 2, X/Y=Cl/PPh2; 4, X/Y=SMe/PPh2).

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Thermally Induced Dehydrogenation of Amine–Borane Adducts and Ammonia–Borane by Group 6 Cyclopentadienyl Complexes Having Single and Triple Metal–Metal Bonds

et al. 2013

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Treatment of solutions of ammonia–borane (NH3·BH3, AB) with catalytic amounts (5 mol‐%) of the singly bonded dimers [M2Cp2(CO)6] [M = Cr (1a), Mo (1b), W (1c); Cp = cyclopentadienyl] under mild thermal activation (333 K) led to the progressive dehydrogenation of the adduct and quantitative conversions were achieved after 12, 24, and >34 h, respectively. At the initial stages of these reactions (low conversions), the major products were cyclic and branched oligomers of aminoborane (NH2=BH2). However, at longer reaction times (high conversions), the major products were, in all cases, borazine, [HNBH]3, and polyborazylene, [NBHx] (x < 1), whereas other minor products were derived from B–N bond‐cleavage processes. Over the course of these reactions, complexes 1a–c were transformed into the corresponding mononuclear hydrides [MCpH(CO)3] [M = Cr (2a), Mo (2b), W (2c)], which are supposed to be the catalytically active species in these processes, as also supported by similar catalytic activity exhibited by pure samples of the dihydride [Mo2Cp2(H)2(μ‐Ph2PCH2PPh2)(CO)2] (2b′). Under similar conditions, 1a–c were also active catalysts for the dehydrogenation of adducts derived from substituted amines (tBuH2N·BH3 and Me2HN·BH3), although the rate of dehydrogenation was significantly lower than that of AB. This lower activity follows from deprotonation of hydrides 2 by the free amines, which are in turn generated through B–N bond‐cleavage processes. The dehydrogenation products of tBuH2N·BH3 are also derived from oligomerization processes of the corresponding aminoborane (tBuHN=BH2), which in this case was identified in the reaction mixtures, but even at long reaction times, the formation of the borazine‐like product was not complete, and the reaction mixture contained significant amounts of (poorly defined) soluble polymeric materials. For Me2HN·BH3, the major product obtained in all of the reactions was cyclic dimer [Me2N=BH2]2. Similar studies were performed with triply bonded complexes [Mo2Cp2(CO)4] (3b) and [Mo2Cp2(μ‐Ph2PCH2PPh2)(CO)2] (3b′), which displayed similar catalytic activity while remaining essentially unperturbed along the reactions, and these complexes yielded product distributions that were similar to those observed for singly bonded dimers 1a–c.

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Hydride transfer reactions in dimolybdenum compounds: a simple route to the novel μ-η1∶η1-tetrahydroboride complex [Mo2Cp2(μ-SMe)3(μ-BH4)]

Cited by 15 publications

References 10 publications

Electrochemical Cleavage of NdN Bonds at a Mo2(μ-SMe)3 Site Relevant to the Biological Reduction of Dinitrogen at a Bimetallic Sulfur Centre

Electrochemical Cleavage of NdN Bonds at a Mo2(μ-SMe)3 Site Relevant to the Biological Reduction of Dinitrogen at a Bimetallic Sulfur Centre

Reaction of BH₄⁻with {Mo₂Cp₂(μ-SMe)_n} species to give tetrahydroborato, hydrido or dimetallaborane compounds: control of product by ancillary ligands

Thermally Induced Dehydrogenation of Amine–Borane Adducts and Ammonia–Borane by Group 6 Cyclopentadienyl Complexes Having Single and Triple Metal–Metal Bonds

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Hydride transfer reactions in dimolybdenum compounds: a simple route to the novel μ-η1∶η1-tetrahydroboride complex [Mo2Cp2(μ-SMe)3(μ-BH4)]

Cited by 15 publications

References 10 publications

Electrochemical Cleavage of NdN Bonds at a Mo2(μ-SMe)3 Site Relevant to the Biological Reduction of Dinitrogen at a Bimetallic Sulfur Centre

Electrochemical Cleavage of NdN Bonds at a Mo2(μ-SMe)3 Site Relevant to the Biological Reduction of Dinitrogen at a Bimetallic Sulfur Centre

Reaction of BH4−with {Mo2Cp2(μ-SMe)n} species to give tetrahydroborato, hydrido or dimetallaborane compounds: control of product by ancillary ligands

Thermally Induced Dehydrogenation of Amine–Borane Adducts and Ammonia–Borane by Group 6 Cyclopentadienyl Complexes Having Single and Triple ­Metal–Metal Bonds

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Reaction of BH₄⁻with {Mo₂Cp₂(μ-SMe)_n} species to give tetrahydroborato, hydrido or dimetallaborane compounds: control of product by ancillary ligands

Thermally Induced Dehydrogenation of Amine–Borane Adducts and Ammonia–Borane by Group 6 Cyclopentadienyl Complexes Having Single and Triple Metal–Metal Bonds