Synthesis and reactions of molybdenocene dimers: X-ray crystal structure of the salt [{(η-C5H5)Mo}2(µ-OH)(µ-H){µ-(η5-C5H4-η5-C5H4)}]2PF6·½H2O

Cooper, N. John; Green, Malcolm L. H.; Couldwell, C.; Prout, Keith

doi:10.1039/c39770000145

Cited by 17 publications

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“…Prolonged treatment of the dimeric complex [Mo(H)Cp( μ -(η 1 :η 5 -C 5 H 4 ))] 2 with aqueous hexafluorophosphoric acid gives the hydroxo complex [{MoCp} 2 ( μ -OH)( μ -H){ μ -(η 5 -C 5 H 4 -η 5 -C 5 H 4 )}]·2PF 6 . The cation consists of two MoCp moieties which are bridged by a H atom, the hydroxyl ligand, and the pentafulvalene ligand, which is η 5 -bonded to the Mo atoms; the structure is similar to the Ti complex shown in Figure , except that a hydride replaces one of the hydroxides .…”

Section: 2 Molybdenummentioning

confidence: 99%

Organometallic Hydroxides of Transition Elements

et al. 2006

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Section: 2 Molybdenummentioning

confidence: 99%

Organometallic Hydroxides of Transition Elements

et al. 2006

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“…Previously reported reactions of N 2 O in homogeneous systems involved complexes of transition metals (Ti, , V, , Cr, , Fe, , Co, − Ni, , Zr, Mo, Ru, − Rh, and Hf 49 ) in low oxidation states. Since N 2 O is a weak ligand with a low binding energy and the N 2 O complex formed with a redox-active metal (such as Ti II and V II ) can be rapidly converted to N 2 and metal-oxidized species, OM n +2 , N 2 O complexes are usually detected only as transient species, and no X-ray structures are available in the literature.…”

Section: Introductionmentioning

confidence: 99%

Mechanism of N₂O Reduction by the μ₄-S Tetranuclear Cu_Z Cluster of Nitrous Oxide Reductase

2005

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Reaction thermodynamics and potential energy surfaces are calculated using density functional theory to investigate the mechanism of the reductive cleavage of the N-O bond by the mu(4)-sulfide-bridged tetranuclear Cu(Z) site of nitrous oxide reductase. The Cu(Z) cluster provides an exogenous ligand-binding site, and, in its fully reduced 4Cu(I) state, the cluster turns off binding of stronger donor ligands while enabling the formation of the Cu(Z)-N(2)O complex through enhanced Cu(Z) --> N(2)O back-donation. The two copper atoms (Cu(I) and Cu(IV)) at the ligand-binding site of the cluster play a crucial role in the enzymatic function, as these atoms are directly involved in bridged N(2)O binding, bending the ligand to a configuration that resembles the transition state (TS) and contributing the two electrons for N(2)O reduction. The other atoms of the Cu(Z) cluster are required for extensive back-bonding with minimal sigma ligand-to-metal donation for the N(2)O activation. The low reaction barrier (18 kcal mol(-)(1)) of the direct cleavage of the N-O bond in the Cu(Z)-N(2)O complex is due to the stabilization of the TS by a strong Cu(IV)(2+)-O(-) bond. Due to the charge transfer from the Cu(Z) cluster to the N(2)O ligand, noncovalent interactions with the protein environment stabilize the polar TS and reduce the activation energy to an extent dependent on the strength of proton donor. After the N-O bond cleavage, the catalytic cycle consists of a sequence of alternating protonation/one-electron reduction steps which return the Cu(Z) cluster to the fully reduced (4Cu(I)) state for future turnover.

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“…The molecular structure of compound (2). C (6) to C(I0) lie behind Mo(l), eclipsed with respect to C(1) to C (5) typical attempt, the compound was protonated and the analytically pure red crystals of ( 6 ) described below were formed. These were treated with base and the resulting reformed dimer (2) was then recrystallised giving crystals of excellent appearance.…”

Section: C(22 Imentioning

confidence: 99%

“…Reactions of Compound (5).-(a) With aqueous hydrochloric acid. Compound ( 5 ) (0.3 g, 0.64 mmol) was stirred with aqueous hydrochloric acid (40 cm3 of an 8 mol dm-3 solution) at 40 "C for 1 h. The aqueous layer became red and a red solid remained.…”

Section: Synthesis Of Compoundmentioning

confidence: 99%

Synthesis, structure, and reactions of a new dimer of molybdenocene, and related bi- and tri-nuclear compounds; molecular structures of [H(η⁵-C₅H₅)₂Mo(µ-σ:η⁵-C₅H₄)Mo(η⁵-C₅H₅)], [(η⁵-C₅H₅)(OC)Mo(µ-η⁵:σ-C₅H₄)Mo(CO)₂(η⁵-C₅H₅)], and [{Mo(η⁵-C₅H₅)}₂(µ-

Bashkin¹,

Green²,

Poveda³

et al. 1982

J. Chem. Soc., Dalton Trans.

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Convenient syntheses of the black dimer [H (q5-C5H5),Mo(p-o :q5-C5H4) Mo(q5-C5H5)] (2) and the compound [(q5-C5H5) (OC)Mo(p-q5 :o-C5H4)Mo(C0),(q5-C5H5)] (5) are described. Compound (2) is a precursor for a number of new and known binuclear molybdenocene derivatives, including cis-or trans-C { Mo(q5-C5H5) H}2(p-o :q5-C5H4)21, [{ Mo(q5-C5H5) H}2(p-q5-C5H4-q5-C5H4) I, [ { M O ( ~~-C , H ~) ) ~( P -H ) (PO) (p-q5-C5H4-q5-C5H4)IPFs, and [{Mo(q5-C,H5)),(p-H) (p-OH) (p-q5-C5H4-q5-C5H4)] [PF6I2. Due t o the variety of structural isomers found in this series of dimers, (2) and (5) were characterised by X-ray diffraction methods. The crystal structure of the trihydride [ { M O ( ~~-C ~H ~) } ~( ~-~~-C ~H ~-~~-C ~H ~) H ~] P F ~ (9) is also reported. Compound (2) is monoclinic, space group P2,/c, with a = 13.674(7), b = 8.012(7), c = 15.37(1) A, p = 108.69(6)", and Z = 4. Refinement converged at R = 0.062, R' = 0.090 for 2 149 observed reflections [I > 30(1)1. The Mo-Mo distance is 3.189(1) A. The carbonyl dimer (5) is monoclinic, space group P 2 , h with a = 8.644(2), b = 15.336(2), c = 12.203(6) A, p = 92.59(3)", and Z = 4. The final R value was 0.033 (R' = 0.045) for 3 574 observed reflections. The Mo-Mo distance is 3.089(1) A. Both (2) and (5) contain a cyclopentadienediyl bridge. Crystals of (9) are orthorhombic, space group Pbcn, with a = 13.030(1), b = 13.302(3), c = 11.446(2) A, and Z = 4. Refinement with 1 284 observed reflections resulted in R = 0.034, R' = 0.037. A fulvalene ligand bridges the t w o M o atoms, which are separated b y 3.227(1) A. The black dimer (2) reacts with aqueous hydrochloric acid to give [ M O ( ~~-C ~H ~) ~C I ~] , providing a convenient laboratory-scale synthesis of this useful compound. The compound [{ M o ( ~~-C ~H ~) ) ~( ~-O -M O O ~) (p-q5-C5H4-q5-C5H4) ]*2Me,SO, which contains a unique p-O-M003 group, is also described. Molybdenocene dimers such as cis-or trans-[{ Mo(q5-C5HS)-H}2(p-o : q5-CsH4)2] and [ { M O ( ~~-C ~H ~) H ) ~( ~-~~-C ~H ~-~~-C5H4)] have been prepared in several different ways '-' and their chemistry has been studied in some detail. One route to the compound [ { M O ( ~~-C ~H ~) H } ~( ~-~~-C ~H ~-~~-C ~H ~) ]proceeds via reaction between the molybdenum acetate dimer [{ Mo(02CMe),},] and sodium cy~lopentadienide.~ We were interested in the mechanism of this reaction and repeated the reaction in the presence of triphenylphosphine in the hope that this would lead to the trapping of some compounds which would suggest the nature of intermediates in the formation of [{ MO(~~-C~H~)H}~(~-~~-C~H~-$-C~H~)]. This study has led to further developments in binuclear molybdenocene chemistry, as described below.

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Synthesis and reactions of molybdenocene dimers: X-ray crystal structure of the salt [{(η-C₅H₅)Mo}₂(µ-OH)(µ-H){µ-(η⁵-C₅H₄-η⁵-C₅H₄)}]2PF₆·½H₂O

Cited by 17 publications

References 0 publications

Organometallic Hydroxides of Transition Elements

Organometallic Hydroxides of Transition Elements

Mechanism of N₂O Reduction by the μ₄-S Tetranuclear Cu_Z Cluster of Nitrous Oxide Reductase

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Synthesis and reactions of molybdenocene dimers: X-ray crystal structure of the salt [{(η-C5H5)Mo}2(µ-OH)(µ-H){µ-(η5-C5H4-η5-C5H4)}]2PF6·½H2O

Cited by 17 publications

References 0 publications

Organometallic Hydroxides of Transition Elements

Organometallic Hydroxides of Transition Elements

Mechanism of N2O Reduction by the μ4-S Tetranuclear CuZ Cluster of Nitrous Oxide Reductase

Synthesis, structure, and reactions of a new dimer of molybdenocene, and related bi- and tri-nuclear compounds; molecular structures of [H(η5-C5H5)2Mo(µ-σ:η5-C5H4)Mo(η5-C5H5)], [(η5-C5H5)(OC)Mo(µ-η5:σ-C5H4)Mo(CO)2(η5-C5H5)], and [{Mo(η5-C5H5)}2(µ-

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Synthesis and reactions of molybdenocene dimers: X-ray crystal structure of the salt [{(η-C₅H₅)Mo}₂(µ-OH)(µ-H){µ-(η⁵-C₅H₄-η⁵-C₅H₄)}]2PF₆·½H₂O

Mechanism of N₂O Reduction by the μ₄-S Tetranuclear Cu_Z Cluster of Nitrous Oxide Reductase