- Reactions of homo- and heterobinuclear cobalt carbonyls with metal carbonyl hydrides
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HMn(CO)5, HMo(CO)3Cp, and HFe(CO)2Cp (Cp = cyclopentadienyl) were found to react with Co2(CO)8 forming HCo(CO)4 and the corresponding mixed-metal carbonyl dimers. It was shown that HMo(CO)3Cp transferred the hydrogen atom to Co2(CO)8 and CoMn(CO)9 in reversible processes. The substituted hydride HMn(CO)4P-n-Bu3 and Co2(CO)8 afforded (CO)4CoMn(CO)4P-n-Bu3 which was characterized by elementary analysis and IR and mass spectroscopy. Its reaction with HMo(CO)3Cp gave HMn(CO)4P-n-Bu3 and CoMo(CO)7Cp. The attack of the hydrides took place in mixed-metal complexes exclusively on the cobalt atom. A mechanism in which the hydrides oxidatively add to a coordinatively unsaturated Co center formed by CO loss is proposed.
- Kovács, István,Sisak, Attila,Ungváry, Ferenc,Markó, László
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- Carborane Stabilized 19-Electron Molybdenum Metalloradical
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Paramagnetic metal complexes gained a lot of attention due to their participation in a number of important chemical reactions. In most cases, these complexes are dominated by 17-e metalloradicals that are associatively activated with highly reactive paramagnetic 19-e species. Molybdenum paramagnetic complexes are among the most investigated ones. While some examples of persistent 17-e Mo-centered radicals have been reported, in contrast, 19-e Mo-centered radicals are illusive species and as such could rarely be detected. In this work, the photodissociation of the [Cp(CO)3Mo]2 dimer (1) in the presence of phosphines was revisited. As a result, the first persistent, formally 19-e Mo radical with significant electron density on the Mo center (22%), Cp(CO)3Mo·PPh2(o-C2B10H11) (5b), was generated and characterized by EPR spectroscopy and MS as well as studied by DFT calculations. The stabilization of 5b was likely achieved due to a unique electron-withdrawing effect of the o-carboranyl substituent at the phosphorus center.
- Jaiswal, Kuldeep,Malik, Naveen,Tumanskii, Boris,Ménard, Gabriel,Dobrovetsky, Roman
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- THERMOCHEMISTRY OF MOLYBDENUM TRICARBONYL COMPLEXES OF ARENES AND CYCLIC POLYOLEFINS
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The heats of reaction of arene, cycloheptatriene, and cyclooctatetraene complexes of molybdenum tricarbonyl with pyridine yielding (py)3Mo(CO)3 have been measured by solution calorimetry.Reaction of toluene molybdenum tricarbonyl with cyclopentadiene yielding HMo(CO)3C5H5 and with tetrahydrofuran yielding (THF)Mp(CO)3 have also been studied thermochemically.These measurements yield accurate values for the enthalpy of arene exchange in methylene chloride solution for a number of organomolybdenum complexes.The order of stability: benzene5-c yclopentadienylhydridoa range of 31 kcal/mol.The enthalpy of isomerization of cycloheptatriene to toluene is reduced by 7.1+/-1.2 kcal/mol upon coordination to molybdenum tricarbonyl, indicative of a loss of resonance energy for the complexed arene.The Mo-H bond strength in HMo(CO)3C5H5 is estimated as 66+/-8 kacl/mol.The importance of entropic factors in arene exchange is discussed.
- Hoff, Carl D.
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- Synthesis and reactivity of diborane(4)yl complexes
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Reaction of various 1,2-dihalodiboranes(4) with Na[(η5-C5H4R)M(CO)3] yielded the diborane(4)yl complexes [X(Me2N)B-B(NMe2){η5-(C5H 4R)M(CO)3}] (5
- Braunschweig, Holger,Koster, Margot
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- Dinuclear Elimination as a Route to Unusual Bridging Carbonyls and Acetyls in Heterobimetallic Complexes
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Reaction of Cp2ZrMe2 with CpMo(CO)3H yields methane and Cp2ZrMeMo(CO)3Cp (1), which has two terminal carbonyl ligands and a third carbonyl with a low (1545 cm-1) stretching frequency.Added gaseous CO inserts into the Zr-Me bond in 1 to form the
- Marsella, John A.,Huffman, John C.,Caulton, Kenneth G.,Longato, Bruno,Norton, Jack R.
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- INFRARED MATRIX ISOLATION EVIDENCE FOR THE FORMATION OF (η5-CYCLOPENTADIENYL)TRICARBONYL-MOLYBDENUM AND -TUNGSTEN RADICALS IN CARBON MONOXIDE MATRICES AT 12 K
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Infrared spectroscopic evidence including 13CO labelling and energy-factored force-field fitting is presented for the first time to show that the radicals (η5-C5H5)M(CO)3 radical (M=Mo, W) and HCO are produced on photolysis of (η5-C5
- Mahmoud, Khalil A.,Rest, Antony J.,Alt, Helmut G.
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- Isolation of two agostic isomers of an organometallic cation: Different structures and colors
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Two of a kind: Two agostic isomers of [CpMo(CO)2(PiPr 3)]+ B(C6F5)4- have been isolated. Both were characterized in the solid state by X-ray crystallography and spectroscopic techniques, and also by DFT calculations. Significantly different LUMO energies cause the difference in color (blue versus orange, see picture) of these isomers. Copyright
- Van Der Eide, Edwin F.,Yang, Ping,Bullock, R. Morris
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- Synthetic and Structural Studies on Group 13 Complexes containing the M(CO)3(η-C5H5) Fragment (M = Cr or Mo). Part 2. Complexes 2>n- (x = 1, n = 0; x = 2, n = 1)
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The synthesis and solution infrared studies of a range of compounds of general formula 2> have been performed where X = Cl or I, L = X, tetrahydrofuran (thf), pyridine (py) and M = Cr, Mo or W.In addition, structures have been determined by X-ray analysis for 2>, 2> and 2> and these are discussed and compared with the structures of related complexes.
- Clarkson, Lucy M.,Clegg, William,Hockless, David C. R.,Norman, Nicholas C.,Farrugia, Louis J.,et al.
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- ARE α-ALKOXYALKYL COMPLEXES SPECIAL? 13C-H COUPLING CONSTANT EVIDENCE
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Complexes of type LnMCH2O2CCMe3 exhibit relatively large values of 1JCH for the α-carbon; however, unexpectedly large values are also found for the methyl analogs, LnMCH3.Thus this technique does not provide evidence for any unusual
- Labinger, Jay A.
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- One-step synthesis and P-H bond cleavage reactions of the phosphanyl complex: Syn -[MoCp{PH(2,4,6-C6H2tBu3)}(CO)2] to give heterometallic phosphinidene-bridged derivatives
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Photolysis of [Mo2Cp2(CO)6] and PH2R? (R? = 2,4,6-C6H2tBu3) yielded the title complex, which turned out to be a versatile precursor of novel heterometallic phosphinidene-bridged complexes via three different P-H bond activation processes: photolysis, deprotonation and reduction. In this way the new complexes [MoReCp(μ-PR?)(CO)n] (n = 6,7), [MoFeCp2(μ-PR?)(CO)m], (m = 3, 4) and [MoAuCp(μ-PR?)(CO)2{P(p-tol)3}] were prepared.
- Alvarez, M. Angeles,Burgos, Mónica,García, M. Esther,García-Vivó, Daniel,Ruiz, Miguel A.,Vega, Patricia
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supporting information
p. 14585 - 14589
(2019/10/16)
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- Synthesis of heterodinuclear hydride complexes by oxidative addition of a transition-metal hydride to Pt(0) and Pd(0) complexes
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Abstract Heterodinuclear hydridoplatinum and -palladium complexes, (dppe)HPt-MLn (MLn = MoCp(CO)3 (3a), WCp(CO)3 (3b)), (dppe)Pt(μ-H)(μ-CO)Mn(CO)4 (3c), (dppe)Pt(μ-H)(μ-CO)FeCp(CO) (3d), cis-L′2HPt-MLn (5aa: LE' = PPh3; MLn = MoCp(CO)3, 5ba: LE' = PPh3; MLn = WCp(CO)3, 5ab: LE' = PMePh2; MLn = MoCp(CO)3, 5ac: LE' = PMe2Ph; MLn = MoCp(CO)3), (dppe)Pd(μ-H)(μ-CO)MLn (MLn = MoCp(CO)2 (7a), WCp(CO)2 (7b)), (dppe)Pd(μ-H)(μ-CO)Mn(CO)4 (7c) are prepared by the oxidative addition of mononuclear transition-metal hydride complexes to zero-valent platinum or palladium complexes. The reactions of the heterodinuclear hydride complexes 3a, 3d and 7a with electron deficient alkenes and alkynes such as dimethyl fumarate or DMAD cause reductive elimination at the Pt or Pd center to give the Pt(alkene or alkyne)(dppe) and MHLn,, suggesting reversibility of this process. The DFT calculations suggest that these reactions are controlled by the thermodynamic stability and the electron rich alkene complex of Pt(0) (or Pd(0)) are preferable to prepare these heterodinuclear hydride complexes by the oxidative addition.
- Komine, Nobuyuki,Kuramoto, Ayako,Yasuda, Toshiyuki,Kawabata, Tatsuya,Hirano, Masafumi,Komiya, Sanshiro
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p. 194 - 205
(2015/08/18)
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- A structural study of [CpM(CO)3H] (M = Cr, Mo and W) by single-crystal X-ray diffraction and DFT calculations: Sterically crowded yet surprisingly flexible molecules
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The single-crystal X-ray structures of the complexes [CpCr(CO) 3H] 1, [CpMo(CO)3H] 2 and [CpW(CO)3H] 3 are reported. The results indicate that 1 adopts a structure close to a distorted three-legged piano stool geometry, wh
- Burchell, Richard P. L.,Sirsch, Peter,Decken, Andreas,McGrady, G. Sean
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p. 5851 - 5857
(2009/12/25)
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- Allyl isomerization mediated by cyclopentadienyl group 6 metal compounds
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Reactions at mild temperatures of the acetonitrile adducts [M(CO) 3(NCMe)3] (M = Mo (1), W (2)) with various substituted cyclopentadienes in THF give the hydrido derivatives [MH{η5- C5R4Si(CH3)2-(CH2CH= CH2)}(CO)3] (M = Mo, R = H (5a), R = CH3 (6), M = W, R = H (7a), R = CH3 (8a)) and [MoH{η5-C 5R4R′}(CO)3] (R = CH3, R′ = H (16); R = H, R′ = SiMe3 (17)) in isolated yields of 60-70%. THF solutions of derivatives 5a, 7a, and 8a undergo isomerization of the cyclopentadienyl-tethered-allyl unit to give the corresponding methyl-vinyl-dimethylsilyl-η5-cyclopentadienyl hydrido compounds [MH{η5-C5R4Si(CH3 2(CH=CHCH3)}(CO)3] (M = Mo, R = H (5b), M = W, R = H (7b), R = CH3 (8b)) in final a:b ratios of ca. 2:1, 2:1, and 1:1, respectively. Solvent polarity seems to be crucial in these transformations. Dehydrogenation and desilylation of 5a in THF solutions to give the dinuclear derivative [Mo{η5-C5H 4Si(CH3)2(CH2CH=CH2) }(CO)3]2 (9) and [MoH(η5-C 5H5)(CO)3] (15), respectively, are processes competitive with the allyl isomerization. Treatment of 5a and 7a with equimolar amounts of ONMe3 permits isolation of pure compound 9 and [W{η5-C5H4Si(CH3) 2(CH2CH=CH2)}(CO)3]2 (10) in isolated yields of 80-90%. Coordination of the olefin pendant unit to the metal was detectable only by reaction of 5a and 7a with [CPh3] [B(C6F5)4] to give the cationic species [M{η5-C5H4Si(CH3) 2(CH2CH=CH2)}(CO)3][B(C 6F5)4] (M = Mo (18), W (19)). Molecular structure determinations by X-ray diffraction methods for derivatives 8a and 9 are also reported.
- Royo, Eva,Acebron, Sergio,Mosquera, Marta Elena Gonzalez,Royo, Pascual
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p. 3831 - 3839
(2008/10/09)
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- Palladium-assisted regioselective olefin insertion into and βhydrogen elimination of hydrogen-molybdenum and -tungsten bonds. Synthesis and reactions of heterodinuclear hydrido complexes of palladium and platinum with molybdenum and tungsten
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Smooth reversible olefin insertion of ethyl acrylate, acrylonitrile, ethylene, dimethyl fumarate, and dimethyl maleate into MHCp(CO)2 (M = Mo (1a), W (1b)) has been catalyzed by Pd(PPh3)4 (4) or Pd(ethyl acrylate)(dppe) (8
- Kuramoto, Ayako,Nakanishi, Kouhei,Kawabata, Tatsuya,Komine, Nobuyuki,Hirano, Masafumi,Komiya, Sanshiro
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p. 311 - 314
(2008/10/09)
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- Synthesis of hydridoplatinum-molybdenum (or tungsten) heterodinuclear complexes by β-hydrogen elimination of (dppe)EtPt-MCp(CO)3. Selective hydride transfer from Pt to Mo (or W)
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Hydridoplatinum-molybdenum (or tungsten) heterodinuclear complexes (dppe)HPt-MCp(CO)3 [M = Mo (1), W (2); dppe = 1,2-bis(diphenylphosphino)ethane] have been prepared by selective β-hydrogen elimination of corresponding ethylplatinum-molybdenum
- Komiya, Sanshiro,Yasuda, Toshiyuki,Fukuoka, Atsushi,Hirano, Masafumi
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- Oxidation of magnesium by tricarbonylcyclopentadienylmolybdenum(II) and tricarbonylcyclopentadienyltungsten(II) chlorides
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The main products of manesium oxidation by tricarbonylcyclopentadienylmolybdenum(II) and tricarhonylcyclopentadienyltungsten(II) chlorides in THF are the corresponding analogs of Grignard reagents and their symmetrization products. Kinetic regularities of the reactions of these molybdenum and tungsten organohalides with magnesium in THF and DMF were established, and thermodynamic parameters of adsorption of the reagents on the magnesium surface were determined.
- Piskunov,Spirina,Artemov,Maslennikov
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p. 1321 - 1324
(2007/10/03)
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- Dimetallagermanes of molybdenum and tungsten: Synthesis, structure and reactions
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Reaction of the trichlorogermyl complexes CpM(CO)3GeCl3 3a or 3b with Li[CpM(CO)3] 2a or 2b, which were obtained from CpM(CO)3H 1a or 1b and LiBun, afforded the dimetalladichlorogermanes [CpM(CO)3]2GeCl2 4a or 4b (Cp = C5H5; a M = Mo; b M = W). Similarly, treatment of Cp*Mo(CO)3GeCl3 3c with K[Cp*Mo(CO)3] 2c yielded selectively [Cp*Mo(CO)3]2GeCl2 4c (Cp* = C5Me5). Complex 3c was obtained from Cp*Mo(CO)3H 1c in two steps. The first step involved an insertion of GeCl2 into the molybdenum-hydrogen bond of 1c to give the dichlorogermyl complex Cp*Mo(CO)3GeCl2H 5c followed by chlorination of 5c with CCl4. The dimetalladichlorogermanes 4a-4c contain two reactive sites for further functionalization, the transition-metal centers and the germanium atom. This has been demonstrated by the CO/PMe3 ligand exchange reaction of 4a to give [Cp(CO)3Mo(μ-GeCl2){trans-Mo(CO)2(PMe 3)Cp}] 6a and the substitution reaction of 4a with LiAlH4 to afford the dimetallagermane [CpMo(CO)3]2GeH2 7a. The crystal structures of 4a, 4b and 6a have been reported.
- Filippou, Alexander C.,Winter, Johannes G.,Kociok-Koehn, Gabriele,Hinz, Isolde
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p. 2029 - 2036
(2007/10/03)
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- Synthesis and characterization of ring-coupled cyclopentadienyl and indenyl bimetallic derivatives of Cr, Mo and W
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A series of new ring-coupled bimetallic complexes M2(CO)6[η5,η5-C5H4-C(CH3)2-C5H4], where M = Cr, Mo, W, was synthesized by reaction of the dianion of the ligand 2,2-bis(cyclopentadienyl)propane and M(CO)3(CH3CN)3, M = Cr, Mo, W. Oxidation with acetic acid-Fe(III) produced the bimetallic complexes in moderate yields. Using the same strategy, reactions of Mo(CO)3(CH3CN)3 with the dianion of 2-cyclopentadienyl-2-indenylpropane produced only the dimer [Mo(CO)3[η5-C5H4-C(CH3)2-C9H7]2 in which the indenyl ring was unmetallated. Subsequent detailed studies revealed that the desired dimetalloanion was initially formed, but that the indenyl bound metal was lost upon protonation. Evidence for the mechanism of this demetallation process is presented. The dimetalloanion could be intercepted by methyl iodide to form [Mo(CO)3CH3]2[η5,η5-C5H4-C(CH3)2-(C9H6)]. Synthesis of Mo2(CO)6[η5,η5-C5H4-C(CH3)2-(3-RC9H5)], where R = H, CH3, was achieved by aprotic oxidation of the intermediate dimetalloanion by ferricinium tetraphenylborate. The molecular structures of two compounds are reported: Mo2(CO)6[η5,η5-C5H4-C(CH3)2-(3-CH3C9H5)]: triclinic, P1, a = 8.777(3) A, b = 9.428(4) A, c = 14.915(4) A, α = 91.42(3)°, β = 102.04(3)°, γ=114.69(3)°, V-1087.9(8) A3, Z = 2, R(F) = 3.03%.[Mo(CO)3CH3]2[η5,η5-C5H4-C(CH3)2-(C9H6)]: triclinic, P1, a = 8.298(6) A, b= 11.662(6) A, c= 13.241(8) A, a = 100.28(1)°, β = 93.02(l)°, γ - 99.72(1)°, V-1238(1) A3, Z=2, R(F) = 3.99.%.
- Fierro, Ricardo,Bitterwolf, Thomas E.,Rheingold, Arnold L.,Yap, Glenn P. A.,Liable-Sands, Louise M.
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- Synthesis and characterization of mo-mo-bonded (fulvalene)dimolybdenum carbonyl complexes containing sterically demanding phosphines
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The new metal-metal-bonded (fulvalene)dimolybdenum carbonyl complexes FvMo2(CO)4L2 (L = PPh3, PCy3, PXy3; Xy = 3,5-dimethylphenyl) were synthesized via (a) hydride hydrogen atom abstraction
- Kovács, István,Baird, Michael C.
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p. 4084 - 4091
(2008/10/09)
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- C-H cleavages in the photoreactions of [M2(η5 -C5H5)2(CO)6](M=Mo,W):Isolation and characterization of the V-shaped trinuclear clusters [M2M′ (μ-η1,η5-C5H4)(η 5-C5H5)2(CO)6](M,M′=Mo or W)
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Irradiation of toluene solutions of the complexes [M2Cp2(CO)6] (M = Mo, W; Cp = η5-C5H5) with UV-visible light at -35°C gives the new trinuclear compounds [M3(μ-η1,η5-C5H 4)Cp2(CO)6] in moderate (M = Mo) or medium (M = W) yields, along with the known complexes [MH(CO)3Cp], [W2(μ-H)2(CO)4Cp2], and [M2Cp2(CO)4]. Similar treatment of equimolar mixtures of [W2Cp2(CO)6] and [Mo2Cp2(CO)4] gives a complex mixture containing (in order of decreasing yield) the mixed-metal compounds [Mo2W(μ-η1,η5-C5H 4)Cp2(CO)6], [MoW2(μ-η1,η5-C5H 4)-Cp2(CO)6] (two isomers), and [W3(μ-η1,η5-C5H 4)Cp2(CO)6], along with [WH(CO)3Cp] as dominant hydrido species. The structure of the new trinuclear compounds has been determined by single crystal X-ray diffraction studies on those species with W3, Mo2W, and W2Mo metal cores. Crystals of the W2Mo compound were found to be an equimolar mixture of both isomers detected in solution, so that two of the three metal positions are best described as 0.5 Mo + 0.5 W. Otherwise, the three crystal structures are virtually identical. These 46 electron molecules exhibit a V-shaped metal core (angle ca. 105°) with a short (ca. 2.52 A?) and a long (ca. 3.12 A?) intermetallic separation the central position being always occupied by a tungsten atom. Each of the metal atoms involved in the short bond carries out a cyclopentadienyl group and a carbonyl ligand which bridges that bond in a linear semibridging fashion. The outer metal atom has also a terminal carbonyl group. Finally, the third metal atom bears a μ-η1,η5-cyclopentadienylidene ligand, σ-bonded to the central tungsten atom, and three terminal carbonyl groups. Variable-temperature 1H NMR spectroscopy reveals that all trinuclear compounds exhibit fluxional behavior in solution, which is thought to result from two independent rearrangements. In addition, the trimolybdenum complex undergoes a slower dynamic process which implies a proton exchange between cyclopentadienylidene and cyclopentadienyl ligands in the molecule, as suggested by 2D EXSY experiments.
- Alvarez, M. Angeles,García, M. Esther,Riera, Víctor,Ruiz, Miguel A.,Bois, Claudette,Jeannin
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p. 1324 - 1335
(2007/10/02)
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- Ionic hydrogenations of hindered olefins at low temperature. Hydride transfer reactions of transition metal hydrides
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Sterically hindered olefins can be hydrogenated at -50 °C in dichloromethane using triflic acid (CF3SO3H) and a hydride donor. Mechanistic studies indicate that these reactions proceed by hydride transfer to the carbenium ion that is formed by protonation of the olefin. Olefins that form tertiary carbenium ions upon protonation are hydrogenated in high yields (90-100%). Styrenes generally produce lower yields of hydrogenated products (50-60%). Suitable hydride donors include HSiEt3 and several transition metal carbonyl hydrides (HW(CO)3Cp, HW(CO)3Cp*, HMo-(CO)3Cp, HMn(CO)5, HRe(CO)5, and HOs(CO)2Cp*; Cp = η-C5H5, Cp* = η5-C5Me5). A characteristic that is required for transition metal hydrides to be effective is that the cationic dihydrides (or dihydrogen complexes) that result from their protonation must have sufficient acidity to transfer a proton to the olefin, as well as sufficient thermal stability to avoid significant decomposition on the time scale of the hydrogenation reaction. Metal hydrides that fail due to insufficient stability of their protonated forms include HMo(CO)2(PPh3)Cp, HMo(CO)3Cp*, and HFe(CO)2Cp*. Other hydrides that fail are those that are protonated to give dihydrides or dihydrogen complexes that are not sufficiently acidic to protonate olefins, as found for HW(CO)2(PMe3)Cp and HRu(CO)(PMe3)Cp.
- Bullock, R. Morris,Song, Jeong-Sup
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p. 8602 - 8612
(2007/10/02)
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- Reaction between transition-metal nucleophiles and alkanedioyl dichlorides: Preparation of five- and six-membered metal-substituted lactone complexes (η5-C5H5)(CO)3M-C:CH(CH 2)nC(O)O (M = Mo, W; n = 1, 2)
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Unsaturated, unconjugated five- and six-membered transition-metal-substituted lactone complexes (η5-C5H5)(CO)3M-C:CH(CH 2)nC(O)O (M = Mo, W; n = 1, 2) are prepared by reacting Na[η5-C5H5)M(CO)3] with succinyl and glutaryl dichlorides. The reaction mechanism involves the formation of a monometallic alkanedioyl chloride complex, followed by a base-assisted cyclization reaction.
- Wong, Andrew,Morgan II, Roger L.,Golder, Jill M.,Quimbita, Grace E.,Pawlick, Robert V.
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p. 844 - 846
(2008/10/08)
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- Phosphido-bridged heterodinuclear complexes of CrPd, MoPd, WPd, and MnPd. X-ray crystal structures of and
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A series of phosphido-bridged heterodinuclear complexes has been prepared by the low temperature reaction of the labile chain complexes trans-2(PhCN)2> (m = Cr, Mo, W(CO)2Cp; Mn(CO)4) with 3 molar equivalents of PCy2H or PPh2H.The crystal struc
- Braunstein, Pierre,Jesus, Ernesto de,Tiripicchio, Antonio,Camellini, Marisa Tiripicchio
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- Synthesis and thermolysis of neutral metal formyl complexes of molybdenum, tungsten, manganese, and rhenium
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The possible intermediacy of catalyst-bound formyls in syngas transformations has prompted efforts to prepare and study the chemistry of transition-metal formyl complexes over more than a decade. We have used a mild borohydride in our reactions with metal carbonyl cations and have introduced some variations into the syntheses which allow, in almost all cases, for the pure formyl complex to be precipitated from solution as it is formed. The formyl complexes and their cationic precursors are shown. Seven of the formyls are new; improved procedures have been established for the other four. All but one of the compounds have been isolated.
- Gibson,Owens,Mandal,Sattich,Franco
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p. 498 - 505
(2008/10/08)
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- Synthesis and reactivity of mercury-bridged transition-metal clusters. 4. Reactivity of (μ3-η2-C2-t-Bu)(CO)9Ru 3HgMo(η5-C5H5)(CO)3
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The thermolysis, photolysis, and phosphine substitution reactions of [Ru3(μ3-η2-C2-t-Bu)(CO) 9] (μ3-Hg)[Mo(η5-C5H5)(CO) 3] (I) and its derivatives have been studied. Redistribution reaction between the two different monophosphine-substituted derivatives of I show that the Hg-Mo bond is relatively labile compared to the μ-Hg-Ru2 bond. Photolysis of I yields the product (μ3-η2-t-Bu)Ru2Mo(η 5-C5H5)(CO)8 (VII), a new triangular mixed-metal cluster. The solid-state structure of VII was determined by X-ray crystallography. Compound VII crystallizes in the monoclinic space group P21/c with a = 9.116 (2) A?, b = 15.982 (3) A?, c = 13.510 (5) A?, β = 108.81 (2)°, V = 2139.1 (8) A?3, and dcalcd = 2.075 g/cm3 for Z = 4. Least-squares refinement led to final agreement indices R = 0.018 and Rw = 0.024 for 3217 observed reflections. An investigation of the ligand dynamics of VII by variable-temperature 13C NMR revealed that there is no intermetallic scrambling of carbonyls around the Ru2Mo triangle, but a restricted edge-hopping motion of the coordinated acetylide between the two Ru-Mo edges is observed.
- Rosenberg, Edward,Wang, Jiandang,Gellert, Robert W.
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p. 1093 - 1100
(2008/10/08)
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- Stepwise synthesis of heteronuclear Pt2M and PdPtM clusters (M = Cr, Mo, W)
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The dinuclear complex (μ-C5H5)(μ-2-MeC3H4)Pt 2(P-i-Pr3)2 (1), which is prepared from (η5-C5H5)Pt-(η3-2-MeC 3H4) and Pt(P-i-Pr3)2, reacts with Me3SiBr to produce the structurally related compound (μ-2-MeC3H4)(μ-Br)Pt2(P-i-Pr 3)2 (4). Reaction of 4 with [(C5H5)M(CO)3]Na (M = Mo, W) leads to displacement of the bridging bromide by the tricarbonyl(cyclopentadienyl)metal anion and formation of the trinuclear clusters (C5H5)(2-MeC3H4)(CO) 3(P-i-Pr3)2Pt2M (5, 6). The analogous mixed-metal PdPtM complexes 9-11 are similarly prepared, starting from (μ-C5H5)(μ-2-MeC3H 4)PdPt(P-i-Pr3)2 (7) via (μ-2-MeC3H4)(μ-Br)-PdPt(P-i-Pr3) 2 (8) as the intermediate that subsequently reacts with [(C5H5)M(CO)3]Na (M = Cr, Mo, W) to form (C5H5)(2-MeC3H4)(CO) 3(P-i-Pr3)2PdPtM (9-11). The IR and 1H, 13C, and 31P NMR spectroscopic data of 5, 6, and 9-11 confirm that the new heteronuclear clusters contain a tetrahedral Pt2MC or PdPtMC framework, the carbon atom of which belongs to a triply bridging CO group.
- Thometzek, Peter,Werner, Helmut
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p. 1169 - 1172
(2008/10/08)
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- Stepwise Formation of Heterometallic Trinuclear and Tetranuclear Clusters from Dipalladium(I) Compounds and Carbonylmetalate Anions. The Crystal and Molecular Structure of (C5H5)2(CO)3(PiPr3)2MoPd2
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The carboxylate- or halide-bridged dinuclear complexes (μ-C5H5)(μ-X)Pd2(PR3)2 (1, 2a-c) react with Na (M = Cr, Mo, W), Na, and to produce the heterometallic trinuclear clusters 3-11.The structure of the MoPd2 compound (C5H5)2(CO)3(PiPr3)2MoPd2 (4) which is also obtained from (μ-C5H5)(μ-tBuCO2)Pd2(PiPr3)2 (1) and C5H5Mo(CO)3SiMe3 has been determined by X-ray analysis. 4 contains a tetrahedral MoPd2C framework, the carbon atom of which belongs to a triply-bridging CO group.The Pd-Pd and Pd-Mo edges of the tetrahedron are further bridged by an allyl-ene type cyclopentadienyl ring and by two semi-bridging CO ligands.Similar trinuclear clusters 15-18 are formed from (μ-2-MeC3H4)(μ-X)Pd2(PiPr3)2 (14a-c) and Na (M = Cr, Mo, W) or Na, respectively.Displacement of the cyclopentadienyl bridge in 4 and 6-8 by chloride and subsequent reaction with Na produces the Pd2M2 clusters 22 and 23a-c.The bonding properties of the heterometallic trinuclear and tetranuclear clusters (possessing 44 and 58 valence electrons, respectively) is briefly discussed.
- Werner, Helmut,Thometzek, Peter,Krueger, Carl,Kraus, Hans-Juergen
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p. 2777 - 2795
(2007/10/02)
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- μ3-Silylidyne Heterometal Clusters
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The silylidyne tricobalt clusters RSiCo3(CO)9 (1, R = Me, Ph, p-Tol) proved to be too sensitive for the conversion to mixed metal clusters by the reported metal exchange procedures.Therefore for the purpose of cluster construction the functional complexes RSiH2 - MLn (2 - 7, MLn = CrCp(CO)3, MoCp(CO)3, WCp(CO)3, Mn(CO)5, FeCp(CO)2, Co(CO)4) were prepared from RSiH2Br (R = Me, Ph) and carbonyl metalates.Their reaction with Co2(CO)8 produced the open trinuclear complexes R(MLn)SiCo2(CO)7 (8 - 10) only for MLn = MoCp(CO)3, WCp(CO)3, and FeCp(CO)2.Subsequent thermolysis resulted in the case of MLn = MoCp(CO)3 and WCp(CO)3 in the mixed metal clusters RSiCo2MCp(CO)8 (11, 12, M = Mo, W).
- Gusbeth, Petra,Vahrenkamp, Heinrich
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p. 1143 - 1153
(2007/10/02)
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- DARSTELLUNG UND CHARAKTERISIERUNG VON METALLACYCLISCHEN ALKENYLKETONKOMPLEXEN DES CHROMS, MOLYBDAENS UND WOLFRAMS. MOLEKUELSTRUKTUR VON
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The photoinduced reaction of η5-ArM(CO)3R complexes (η5-Ar = C5H5, C5H4Me,C5Me5, C9H7; M = Cr, Mo, W; R = Me, Et, nPr, nBu) with symmetrical and asymmetrical alkynes, R1CCR2 (R1/su
- Alt, Helmut G.,Engelhardt, Heidi E.,Thewalt, Ulf,Riede, Juergen
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p. 165 - 178
(2007/10/02)
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- Comparative Photochemistry of Tricarbonyl(η5-cyclopentadienyl)methyl- and -ethyl-molybdenum and -tungsten in Poly(vinyl chloride) Film Matrices at 12-298 K
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The photoreactions of 5-C5H5)(CO)3(CH3)> and 5-C5H5)(CO)3(C2H5)> complexes (M = Mo or W) in poly(vinyl chloride) (pvc) film matrices over a wide temperature range have been monitored using i.r. spectroscopy.At 298 K the methyl complexes dealkylate on irradiation (λ > 300 nm) to form 5-C5H5)(CO)3Cl>, 5-C5H5)(CO)3H>, and 5-C5H5)2(CO)6>.Photolysis at 12 K leads primarily to the formation of 5-C5H5)(CO)2(CH3)>.In the case of molybdenum, M-CH3 bond cleavage also occurs at 12 K and the complexes 5-C5H5)(CO)3Cl> and 5-C5H5)(CO)3H> are generated on warming the matrices.Photolysis of 5-C5H5)(CO)3(C2H5)> at 12 K proceeds with the formation of 5-C5H5)(CO)2(C2H5)> which rearranges photochemically or thermally to form trans-5-C5H5)(CO)2(C2H4)H>.The cis-ethylene-hydride complex is also observed for tungsten at temperatures below ca. 50 K.At 298 K, photolysis of 5-C5H5)(CO)3(C2H5)> leads directly to trans-5-C5H5)(CO)2(C2H4)H> which reacts further to form 5-C5H5)(CO)3H>, 5-C5H5)(C0)2(C2H4)Cl>, 5-C5H5)(CO)3Cl>, and 5-C5H5)2(CO)6>.However, on photolysis of 5-C5H5)(CO)3(C2H5)> at 298 K the main product observed is with trace amounts of 5-C5H5)(CO)3H>, 5-C5H5)(CO)3Cl>, and 5-C5H5)2(CO)6>.
- Hooker, Richard H.,Rest, Antony J.
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p. 761 - 770
(2007/10/02)
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- [(C5H5)2TiOCMo(CO)2(C 5H4CH3)]2: A 12-membered organometallic ring system held together by Ti-O-C-Mo bridges
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The reaction between (C5H5)2Ti(CO)2 and (C5H4CH3)Mo(CO)2≡Mo(CO) 2(C5H4CH3) in toluene at room temperature leads to the formation of [(C5H5)2TiOCMo(CO)2(C 5H4CH3)]2, 2a. Complex 2a was found to crystallize in the monoclinic space group P21/n with two molecules in a unit cell of dimensions a = 13.510 (4) ?, b = 10.951 (2) ?, c = 13.361 (3) ?, β = 114.66 (2)°, V = 1797 (1) ?3, and dcalcd = 1.616 g cm-3. The core of 2a consists of an unusual 12-membered ring: Ti-O-C-Mo-C-O-Ti-O-C-Mo-C-O. Each titanium atom is further bound by two η5-C5H5 ligands while each molybdenum is further bound by one terminal carbonyl and one η5-C5H4CH3 ligand. Complex 2a reacts with the donor tetrahydrofuran to form the known complex (C5H5)2Ti(THF)OCMo(CO)2-(C 5H4CH3), 1a.
- Merola, Joseph S.,Campo, Kathryn S.,Gentile, Robert A.,Modrick, Michelle A.,Zentz, Susan
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p. 334 - 337
(2008/10/08)
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- GEZIELTE SYNTHESE DREIKERNIGER HETEROMETALL-CLUSTER MIT VIER VERSCHIEDENEN GERUESTATOMEN
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The trinuclear heterometallic cluster Va-Vc possessing a tetrahedral framework of four different atoms (MPdPtC) have been prepared from (μ-2-MeC3H4)(μ-Br)PdPt(PPr3i)2 (IV) and Na (M = Cr, M, W).Complex IV is obtained from (μ-2-MeC3H4)(μ-C5H5)PdPt(PPr3i)2 and Me3SiBr by bridge-ligand exchange.Following the same concept, the synthesis of the Pt2Mo and Pt2W heterometallic clusters VIIIa, VIIIb has also been achieved.
- Thometzek, P.,Werner, H.
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p. C29 - C34
(2007/10/02)
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- Synthesis and molecular structure of [Dicyclopentadienyl(tetrahydrofuran)titanium](μ-η 2-carbonyl)cyclopentadienyldicarbonylmolybdenum
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1982 American Chemical Society Reaction of Cp2Ti(CO)2 with [CpMo(CO)2]2 in THF yields the novel complex Cp2Ti(THF)OCMo(CO)2Cp, 1, containing a μ,-η2 metal carbonyl bridge between the Ti and Mo. The structure of 1 has been determined from single-crystai X-ray diffraction data. The compound was found to crystallize in the monoelnic space group P21/a with unit cell dimensions of a = 14,333 (2) A?, b = 10.783 (3) A?, c = 14.051 (3) A?, β= 109.19 (2)°, Z = 4, d(calcd) = 1.601 g cm-3, and V = 2050.9 (1.4) A?3.
- Merola, Joseph S.,Gentile, Robert A.,Ansell, Gerald B.,Modrick, Michelle A.,Zentz, Susan
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p. 1731 - 1733
(2008/10/08)
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- THE REACTION OF FORMYL FLUORIDE WITH TRANSITION METAL COMPLEXES
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Formyl fluoride reacts with metal carbonyl anions in a manner similar to acetic formic anhydride.Although formyl complexes may have been formed as unstable intermediates, no neutral formyl complexes could be isolated but rather the expected decomposition products, the metal carbonyl hydrides or dimers, were produced.The attempted oxidative addition of formyl fluoride to various coordinately unsaturated metal complexes also did not result in the formation of formyl derivatives.HF adducts were obtained from the reaction of Ir(CO)Cl(PR3)2 or M(PPh3)4 (M=Pt or Pd) with formyl fluoride whereas Ru(NO)Cl(PPh3)2 and Rh(PPh3)3Cl give the CO complexes Ru(NO)(CO)Cl(PPh3)2 and Rh(CO)Cl(PPh3)2, respectively.
- Doyle, Gerald
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p. 355 - 362
(2007/10/02)
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- Thermal and photochemical reactions of dinuclear metal carbonyl compounds with metal hydrides
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The thermal or photochemical reaction of bis(tri-n-butylphosphine)hexacarbonyldicobalt, Co2(CO)6[P(n-Bu)32, with tri- n-butyltin hydride, HSn(n-Bu)3, leads to H2 and (rc-Bu)3SnCo(CO)3P(ra-Bu)3 as products. The rate law for the photochemical reaction and product distribution are consistent with a pathway involving loss of CO from the Co(CO)3P(ra-Bu)3- radical following metal-metal bond rupture, oxidative addition of the H-Sn bond to the cobalt center, a hydrogen atom transfer from a second HSn(n-Bu)3 to cobalt, and then a reductive elimination of H2, as the pathway for reaction. A similar reaction pathway is indicated for reaction of (η-C5H5)2M2(CO)6 (M = Mo, W) with HSn(n-Bu)3 or (η5-C5H5)2Mo 2(CO)6 with HMo(CO)3(η5-C5H5). On the other hand reaction of (η-C5H5)2Mo2(CO)6 with HMn(CO)5 leads to HMo(CO)3(η5-C5H5) and Mn2(CO)10 as products, suggesting a simple hydrogen atom transfer reaction between the Mo(CO)3(η5-C5H5)- radical and HMn(CO)5. The choice between the oxidative addition and hydrogen atom transfer pathways is determined by the donor M-H bond energy; a low M-H bond energy favors hydrogen atom transfer. On the basis of studies to date, the oxidative addition pathway, as described above, is the more common. Reaction of HMo(CO)3(7/5-C5H5) with HSn(n-Bu)3 leads to (n-Bu)3SnMo(CO)3(η5-C5H 5) and H2. The rate law is of the form d(product)/dt = {κa[HSn(n-Bu)3]/(κa + κc[HSn(n-Bu)3])}[HMo(CO)3(η 5-C5H5]. The rate law suggests the existence of a preequilibrium involving either a formyl intermediate, formed via a hydride migration, or a change in hapticity of the cyclopentadienyl ring to form a -cyclopentadienyl intermediate.
- Wegman, Richard W.,Brown, Theodore L.
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- PHOTOINDUZIERTE UND THERMISCHE REAKTIONEN DER UEBERGANGSMETALLETHYLVERBINDUNGEN CpM(CO)3Et (Cp = η5-CYCLOPENTADIENYL; Et = ETHYL; M = Mo, W)
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In the compounds CpM(CO)3Et (M = Mo, W) the metal-ethyl ?-bond is photolabile.Upon irradiation of a solution of CpM(CO)3Et with UV light mainly 2, CpM(CO)3H, ethane, and ethylene are produced.Formation of CpM(CO)3H is indicative of a β-elimination pathway for the photoinduced degradation.In the presence of trimethylphosphane (L) UV-irradiation of a solution of CpM(CO)3Et leads to the products Cp(CO)(L)2M-M(CO)3Cp, CpM(CO)2(L)Et and CpM(CO)2(L)H, while the thermal reaction produces the propionyl complexes CpM(CO)2(L)(COEt).
- Alt, H. G.,Eichner, M. E.
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p. 397 - 403
(2007/10/02)
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