Low Temperature Multinuclear NMR Study of the Mechanism of Protonation of W(H)2Cl2(PMe2Ph)4

Rothfuss, Helmut; Gusev, Dmitry G.; Caulton, Kenneth G.

doi:10.1021/ic00115a017

Cited by 12 publications

(6 citation statements)

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“…In this regard, Caulton has suggested that the chloro ligand in the related complex W(PMe 2 Ph) 4 Cl 2 H 2 exhibits enhanced nucleophilicity. See refs and .…”

Section: Referencesmentioning

confidence: 99%

False Minima in X-ray Structure Solutions Associated with a “Partial Polar Ambiguity”: Single Crystal X-ray and Neutron Diffraction Studies on the Eight-Coordinate Tungsten Hydride Complexes, W(PMe₃)₄H₂X₂ (X = F, Cl, Br, I) and W(PMe₃)₄H₂F(FHF)

et al. 1998

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The molecular structures of the eight-coordinate tungsten hydride complexes W(PMe3)4H2X2 (X = F, Cl, Br, I) and W(PMe3)4H2F(FHF) have been determined by single-crystal X-ray diffraction; W(PMe3)4H2Cl2 and W(PMe3)4H2F(FHF) have also been analyzed by single-crystal neutron diffraction, thereby accurately locating the positions of the hydride ligands. The structures of all of these complexes are similar and are based on a trigonal dodecahedron, with a distorted tetrahedral array of PMe3 ligands in which two of the PMe3 ligands are displaced over the halide substituents. However, the initial structures derived for both W(PMe3)4H2Cl2 and W(PMe3)4H2F(FHF) did not exhibit the aforementioned geometry, but were based on an arrangement in which the two transoid-PMe3 ligands are displaced toward the two cis-PMe3 groups, rather than tilted toward the chloride ligands. Interestingly, the unexpected structures for W(PMe3)4H2Cl2 and W(PMe3)4H2F(FHF) were discovered to be the result of an artifact due to the presence of a heavy atom in a polar space group, which allowed the X-ray structure solutions to refine into most deceptive false minima. Specifically, for the structures corresponding to the false minima, the transoid-PMe3 ligands were incorrectly located in positions that are related to their true locations by reflection perpendicular to the polar axis. In effect, the incorrect molecular structures are a composite of the two possible true polar configurations which are related by a reflection perpendicular to the polar axis, i.e. a “partial polar ambiguity”. Of most importance, the solutions corresponding to the false minima are characterized by low R values and well-behaved displacement parameters, so that it is not apparent that the derived structures are incorrect. Thus, for space groups with a polar axis, it is necessary to establish that all of the atoms in the asymmetric unit belong to a single true polar configuration.

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“…In this regard, Caulton has suggested that the chloro ligand in the related complex W(PMe 2 Ph) 4 Cl 2 H 2 exhibits enhanced nucleophilicity. See refs and .…”

Section: Referencesmentioning

confidence: 99%

False Minima in X-ray Structure Solutions Associated with a “Partial Polar Ambiguity”: Single Crystal X-ray and Neutron Diffraction Studies on the Eight-Coordinate Tungsten Hydride Complexes, W(PMe₃)₄H₂X₂ (X = F, Cl, Br, I) and W(PMe₃)₄H₂F(FHF)

et al. 1998

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“…Sparked by the potentials of industrial catalysis, reversible hydrogen storage, and the development of biomimetic hydrogen activating systems, the interest in transition metal hydride complexes has led to tremendous advances in the past 15−20 years, ranging from the existence and properties of coordinated H 2 ligands (so-called nonclassical hydride complexes) − to the existence of stable paramagnetic transition metal mono- and polyhydride complexes, − and from the mechanism of fluxional rearrangements 12-14 to M−H δ- ···H δ+ hydrogen bonding. − The simplicity of the ligand under scrutiny (the hydrogen atom) has made the bond between transition metals and H a favorite subject for a variety of investigations including structural (X-ray and neutron diffraction and T 1 NMR), ,− theoretical, − and reactivity studies including protonation − and oxidation. ,− …”

Section: Introductionmentioning

confidence: 99%

Stable Paramagnetic Half-Sandwich Mo(V) and W(V) Polyhydride Complexes. Structural, Spectroscopic, Electrochemical, Theoretical, and Decomposition Mechanism Studies of [Cp*MH₃(dppe)]⁺ (M = Mo, W)

et al. 1999

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HAL is a multi-disciplinary open access archive for the deposit and dissemination of scientific research documents, whether they are published or not. The documents may come from teaching and research institutions in France or abroad, or from public or private research centers. L'archive ouverte pluridisciplinaire HAL, est destinée au dépôt et à la diffusion de documents scientifiques de niveau recherche, publiés ou non, émanant des établissements d'enseignement et de recherche français ou étrangers, des laboratoires publics ou privés.

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“…Transition metal polyhydride systems have been the focus of much recent attention. The determination of classical and nonclassical hydrides, − the mechanism of hydride fluxionality, and other studies on oxidation − or protonation − of these systems have been reported in recent years. The (ring)MH 3 L 2 polyhydride system (M = Mo or W) has been known since 1979 but has not been the subject of detailed studies.…”

Section: Introductionmentioning

confidence: 99%

Synthesis, Structure, and Hydride−Deuteride Exchange Studies of CpMoH₃(PMe₂Ph)₂ and Theoretical Studies of the CpMoH₃(PMe₃)₂ Model System

Abugideiri¹,

Fettinger²,

Pleune³

et al. 1997

Organometallics

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The synthesis and characterization of CpMoH 3 (PMe 2 Ph) 2 , 1, is described. Compound 1 is obtained from the reaction between CpMoCl 3 , PMe 2 Ph, and LiAlH 4 , in 61% yield. Compound 1 has also been obtained from the reaction of CpMo(o-C 6 H 4 PMe 2 )(PMe 2 Ph) 2 with H 2 . Characterization of 1 by 1 H-and 31 P-NMR spectroscopies shows a high degree of fluxionality for the hydride atoms, even at low temperatures. A single-crystal X-ray structure indicates that the geometry is pseudo-octahedral, with a relative mer arrangement of the three H ligands and the two PMe 2 Ph ligands occupying relative trans positions. This is in contrast with the only other previously reported structure of a Mo(IV) trihydride, Cp*MoH 3 (dppe), which adopts a pseudo trigonal prismatic structure. The Mo-P (average 2.41(8) Å) and Mo-H distances (average 1.64(4) Å) are similar to those found in Cp*MoH 3 (dppe). The closest H-H distance is 1.79 Å, consistent with a classical hydride. The results of ab initio calculations for the CpMoH 3 (PMe 3 ) 2 model in different configurations agree with the experimental observations and suggest that a mechanism of hydride exchange consisting of a Bailar twist, which interconverts pseudo-octahedral mer, trans and fac geometries, is possible. The process of hydride-deuteride exchange of 1 in C 6 D 6 is also examined.

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Low Temperature Multinuclear NMR Study of the Mechanism of Protonation of W(H)2Cl2(PMe2Ph)4

Cited by 12 publications

References 0 publications

False Minima in X-ray Structure Solutions Associated with a “Partial Polar Ambiguity”: Single Crystal X-ray and Neutron Diffraction Studies on the Eight-Coordinate Tungsten Hydride Complexes, W(PMe₃)₄H₂X₂ (X = F, Cl, Br, I) and W(PMe₃)₄H₂F(FHF)

False Minima in X-ray Structure Solutions Associated with a “Partial Polar Ambiguity”: Single Crystal X-ray and Neutron Diffraction Studies on the Eight-Coordinate Tungsten Hydride Complexes, W(PMe₃)₄H₂X₂ (X = F, Cl, Br, I) and W(PMe₃)₄H₂F(FHF)

Stable Paramagnetic Half-Sandwich Mo(V) and W(V) Polyhydride Complexes. Structural, Spectroscopic, Electrochemical, Theoretical, and Decomposition Mechanism Studies of [Cp*MH₃(dppe)]⁺ (M = Mo, W)

Synthesis, Structure, and Hydride−Deuteride Exchange Studies of CpMoH₃(PMe₂Ph)₂ and Theoretical Studies of the CpMoH₃(PMe₃)₂ Model System

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Low Temperature Multinuclear NMR Study of the Mechanism of Protonation of W(H)2Cl2(PMe2Ph)4

Cited by 12 publications

References 0 publications

False Minima in X-ray Structure Solutions Associated with a “Partial Polar Ambiguity”: Single Crystal X-ray and Neutron Diffraction Studies on the Eight-Coordinate Tungsten Hydride Complexes, W(PMe3)4H2X2 (X = F, Cl, Br, I) and W(PMe3)4H2F(FHF)

False Minima in X-ray Structure Solutions Associated with a “Partial Polar Ambiguity”: Single Crystal X-ray and Neutron Diffraction Studies on the Eight-Coordinate Tungsten Hydride Complexes, W(PMe3)4H2X2 (X = F, Cl, Br, I) and W(PMe3)4H2F(FHF)

Stable Paramagnetic Half-Sandwich Mo(V) and W(V) Polyhydride Complexes. Structural, Spectroscopic, Electrochemical, Theoretical, and Decomposition Mechanism Studies of [Cp*MH3(dppe)]+ (M = Mo, W)

Synthesis, Structure, and Hydride−Deuteride Exchange Studies of CpMoH3(PMe2Ph)2 and Theoretical Studies of the CpMoH3(PMe3)2 Model System

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False Minima in X-ray Structure Solutions Associated with a “Partial Polar Ambiguity”: Single Crystal X-ray and Neutron Diffraction Studies on the Eight-Coordinate Tungsten Hydride Complexes, W(PMe₃)₄H₂X₂ (X = F, Cl, Br, I) and W(PMe₃)₄H₂F(FHF)

False Minima in X-ray Structure Solutions Associated with a “Partial Polar Ambiguity”: Single Crystal X-ray and Neutron Diffraction Studies on the Eight-Coordinate Tungsten Hydride Complexes, W(PMe₃)₄H₂X₂ (X = F, Cl, Br, I) and W(PMe₃)₄H₂F(FHF)

Stable Paramagnetic Half-Sandwich Mo(V) and W(V) Polyhydride Complexes. Structural, Spectroscopic, Electrochemical, Theoretical, and Decomposition Mechanism Studies of [Cp*MH₃(dppe)]⁺ (M = Mo, W)

Synthesis, Structure, and Hydride−Deuteride Exchange Studies of CpMoH₃(PMe₂Ph)₂ and Theoretical Studies of the CpMoH₃(PMe₃)₂ Model System