12128-26-6Relevant articles and documents
Phosphido-bridged heterodinuclear complexes of CrPd, MoPd, WPd, and MnPd. X-ray crystal structures of and
Braunstein, Pierre,Jesus, Ernesto de,Tiripicchio, Antonio,Camellini, Marisa Tiripicchio
, p. C5 - C10 (1989)
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
The enthalpy of insertion of sulfur into the metal-hydrogen bond. Synthetic, structural, and calorimetric study of the complexes HS-M(CO)3C5R5 [M = Cr, Mo, W; R = H, Me]
Bauer, Andreas,Capps, Kenneth B.,Wixmerten, Bodo,Abboud, Khalil A.,Hoff, Carl D.
, p. 2136 - 2142 (1999)
Synthetic and calorimetric studies of the sulfhydryl complexes HS-M(CO)3C5R5 (M = Cr, R = Me; M = Mo, W, R = H, Me) are reported. The Mo and W complexes can be obtained in high yield by reaction of the hydrido complexes H-M(CO)3C5R5 with Ph3Sb=S, which readily undergoes single S atom transfer to the metal-hydrogen bond yielding the metal-sulfhydryl complex. Direct reaction between the metal hydrides and a limited amount of sulfur also yields the sulfhydryl complexes as the dominant organometallic product. At sulfur atom/metal hydride ratios higher than 1/1, additional products formulated as HSn-M(CO)3C5R5 are detected. The enthalpies of insertion of sulfur from Ph3Sb=S and S8 into the metal-hydrogen bond have been determined by solution calorimetry. The HS-M(CO)3C5R5 complexes (M= Mo, W) are readily desulfurized by PCy3 for R = H, but not for R = Me. The M-SH bond strength estimates for the complexes HS-M(CO)3C5Me5 increases in the order Cr (46) 3C5Me5 group has a pKa value at least 4 pKa units less acidic than that of H-Mo(CO)3C5Me5. The crystal structure of HS-Mo(CO)3C5Me5 is reported.
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
Burchell, Richard P. L.,Sirsch, Peter,Decken, Andreas,McGrady, G. Sean
, p. 5851 - 5857 (2009)
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
PHOTOINDUZIERTE UND THERMISCHE REAKTIONEN DER UEBERGANGSMETALLETHYLVERBINDUNGEN CpM(CO)3Et (Cp = η5-CYCLOPENTADIENYL; Et = ETHYL; M = Mo, W)
Alt, H. G.,Eichner, M. E.
, p. 397 - 403 (1981)
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).
Dimetallagermanes of molybdenum and tungsten: Synthesis, structure and reactions
Filippou, Alexander C.,Winter, Johannes G.,Kociok-Koehn, Gabriele,Hinz, Isolde
, p. 2029 - 2036 (1998)
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.
Haloalkyl complexes of the transition metals. VIII. The synthesis and properties of (X = OCH3, Cl, Br, I) and their reactivity with neutral donor ligands
Friedrich, Holger B.,Moss, John R.
, p. 85 - 95 (1993)
The complexes (Cp = η5-C5H5, X = Cl, Br, I) have been prepared.Their reactions with a series of tertiary phosphines, amines, SMe2 and AsPh3 in THF, CH3CN, CH2Cl2 and MeOH have been investigated.Two types of cationic products, namely the ylide complexes + and the disubstituted complexes +, were obtained, the outcome depending on the halide (X), the pKa, cone angle and concentration of the ligand (L), and the solvent used.These variables were also found to have significant influence on the reaction rates.The reactions of with L were found to be significantly slower than those of the analogous complexes with the same ligands.
Reactivity of 17-electron organometallic tungsten and molybdenum radicals: A laser flash photolysis study
Scott, Susannah L.,Espenson, James H.,Zhu, Zuolin
, p. 1789 - 1797 (1993)
Visible (460-490 nm) laser flash photolysis of [CpW(CO)3]2 or [CpMo(CO)3]2 induces homolysis of the metal-metal bond with formation of 17-electron radicals, CpM(CO)3. Radical dimerization results in quantitative recovery of the parent dimer and can be followed by the time-resolved increase in dimer absorbance. The reaction follows clean second-order kinetics, -d[CpM(CO)3]/dt = 2kc[CpM(CO)3]2; kc(W) = 6.2 × 109 and kc(Mo) = 3.9 × 109 L mol-1 s-1 in CH3CN at 23°C. The CpM(CO)3 radicals react with organic and inorganic halides and pseudohalides by an atom-transfer mechanism. In the presence of a large excess of the halide-containing substrate, the rate of loss of the radical, -d[CpM(CO)3]/dt, proceeds according to a mixed first- and second-order rate law. The pseudo-first-order rate constants for reactions with organic halides vary linearly with the concentration of the organic halide; bimolecular rate constants for CpW(CO)3 range from 3.9 × 102 L mol-1 s-1 with CH2Br2 to 1.34 × 109 L mol-1 s-1 for CBr4. The reactivity trends (RI > RBr > RCl) and (benzyl > allyl > 3° > 2° > 1° > CH3) are observed. The 7 orders of magnitude variation in bimolecular rate constants is attributed to a highly selective atom abstraction process. The range of rate constants for atom abstraction from halo- and pseudohalopentaamminecobalt(III) and halobis(dimethylglyoximato)cobalt(III) complexes is smaller (2 orders of magnitude, from 1.6 × 107 L mol-1 s-1 for NCCo(NH3)52+ to > 2 × 10- L mol-1 s-1 for BrCo(dmgH)2py), because of the upper limit imposed by diffusion. Transfer of the halogen atom from both organic and metal substrates to CpW(CO)3 was confirmed by the IR spectrum of the organometallic product, CpW(CO)3X (X = Cl, Br, or I). Dioxygen traps CpW(CO)3 with a rate constant k = 3.3 × 109 L mol-1 s-1. Light-initiated chain reactions were observed at high concentrations of RX, XCoL5nt, or O2. Hydroperoxides react with CpW(CO)3 by a radical mechanism. The reaction observed between CpW(CO)3 and (n-Bu)3SnH is not consistent with either outer-sphere electron transfer or a hydrogen atom abstraction mechanism; oxidative addition to the 17-electron radical is believed to occur in this case. The dimer [(C5H4COOCH3)W(CO)3]2 shows photoreactivity in organic solvents which is very similar to that of [CpW(CO)3]2.
Homogeneous pressure hydrogenation of quinolines effected by a bench-stable tungsten-based pre-catalyst
Heizinger, Christian,Topf, Christoph,Vielhaber, Thomas
, p. 451 - 461 (2021/11/11)
We report on an operationally simple catalytic method for the tungsten-catalyzed hydrogenation of quinolines through the use of the easily handled and self-contained precursor [WCl(η5-Cp)(CO)3]. This half sandwich complex is indefinitely storable on the bench in simple screw-capped bottles or stoppered flasks and can, if required, be prepared on a multi-gram scale while the actual catalytic transformations were performed in the presence of a Lewis acid in order to achieve both decent substrate conversions and product yields. The described method represents a facile and atom-efficient access to a variety of 1,2,3,4-tetrahydroquinolines that circumvents the use of cost-intensive and oxygen-sensitive phosphine ligands as well as auxiliary hydride reagents.
Acid-base interaction between transition-metal hydrides: Dihydrogen bonding and dihydrogen evolution
Levina, Vladislava A.,Rossin, Andrea,Belkova, Natalia V.,Chierotti, Michele R.,Epstein, Lina M.,Filippov, Oleg A.,Gobetto, Roberto,Gonsalvi, Luca,Lledos, Agusti,Shubina, Elena S.,Zanobini, Fabrizio,Peruzzini, Maurizio
, p. 1367 - 1370 (2011/04/18)
Reaction of the acidic tungsten(II) hydride 2 with the nickel(II) pincer complex 1 in either THF or toluene after an initial dihydrogen bonding (DHB) interaction led to the formation of the Ni-W bimetallic species 3 (see picture). The first example of DHB between two metal hydrides with opposite polarity was analyzed by NMR and IR spectroscopy, X-ray crystallography, and DFT calculations.
Reactivity of the unsaturated hydride [Mo2(η5- C5H5)2(μ-H)(μ-PCy2)(CO) 2] toward 17- and 16-electron metal carbonyl fragments: Rational synthesis of electron-deficient heterometallic clusters
Alvarez, Celedonio M.,Alvarez, M. Angeles,Garcia, M. Esther,Ramos, Alberto,Ruiz, Miguel A.,Graiff, Claudia,Tiripicchio, Antonio
, p. 321 - 331 (2008/10/09)
Reactions of the 30-electron hydride [Mo2Cp2(μ-H) (μ-PCy2)(CO)2] (Cp = η5-C 5H5) with the 17-electron-fragment precursors [M 2Cp2(CO)n] (M = Mo, W, n = 6; M = Ru, n = 4) or [Mn2(CO)10] lead to the 46-electron clusters [Mo 2MCp3(μ-PCy2)(μ3-CO)(CO) 4] (M = Mo, W), [Mo2RuCp3(μ-PCy 2)(μ-CO)(CO)3], and [MnMo2Cp 2(μ-PCy2)(μ-CO)2(CO)5]. The structure of the trimolybdenum cluster was confirmed by an X-ray diffraction study and displays two long (ca. 3.1 A) and one short Mo-Mo distance (2.743(1) A). The title unsaturated hydride also proved to be highly reactive toward the appropriate precursors of 16-electron fragments such as M(CO) 5 (M = Cr, Mo, W) and MnCp′(CO)2 (Cp′ = η5-C5H4CH3), then leading to the 46-electron hydride clusters [MMo2Cp2(μ3-H) (μ-PCy2)(CO)7] (M = Cr, Mo, W) and [MnMo 2Cp2Cp′(μ3-H)(μ-PCy 2)(CO)4]. The structures of the compounds having Mo 2W and Mo2Mn skeletons were also determined by X-ray diffraction methods, both of them displaying Mo-Mo distances (ca. 2.6 A) somewhat shorter than expected for double Mo=Mo bonds and Mo - M distances longer than the corresponding single-bond lengths. A similar reaction takes place with the 12-electron compound CuCl, to give the hydride [CuMo 2ClCp2(μ3-H)(μ-PCy2)(CO) 2]. In contrast, the reaction of the title hydride with [Fe 2(CO)9], a precursor of the 16-electron fragment Fe(CO)4, gives the heterodinuclear complex [FeMo(μ-PCy 2)(CO)6] (Fe - Mo = 2.931(1) A).
