Influence of a cis hydride on a coordinated molecular hydrogen ligand cis hydride, Ab initio calculations

Riehl, Jean Frederic; Pélissier, Maud; Eisenstein, Odile

doi:10.1021/ic00042a003

Cited by 26 publications

(18 citation statements)

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“…The dihydrogen and hydride ligands in 1 are highly fluxional on the NMR time scale and, therefore, the measured J (H,D) of 4.7 Hz is an average resulting from the dynamic H,D exchange between the H 2 molecule and the two hydride ligands. Similar effects have been observed in related complexes such as FeH 2 (η 2 -H 2 )(PEtPh 2 ) 3 and Tp Me 2 RuH(η 2 -H 2 ) 2 …”

Section: Introductionsupporting

confidence: 82%

“…Therefore, the barrier height, derived from measurements of the rotational transitions, provides an indication of the strength of the back-bonding interaction. In addition to the direct σ- and π-interactions between the metal center and dihydrogen (which depends on the coligands), EHMO and ab initio calculations have shown that, in the case of the above iron complex, the barrier height is also affected by the presence of hydride ligands cis to coordinated dihydrogen ( cis effect). , …”

Section: Introductionmentioning

confidence: 99%

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Nature of the Rh−H₂ Bond in a Dihydrogen Complex Stabilized Only by Nitrogen Donors. Inelastic Neutron Scattering Study of Tp^Me^₂RhH₂(η²-H₂) (Tp^Me^₂ = Hydrotris(3,5-dimethylpyrazolyl)borate)

et al. 1996

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The tunnel splitting of the librational ground state and the torsional frequencies of the dihydrogen ligand in Tp(Me)()2RhH(2)(eta(2)-H(2)) (Tp(Me)()2 = hydrotris(3,5-dimethylpyrazolyl)borate) were measured using inelastic neutron scattering spectroscopy. The barrier for the rotation of the H(2) ligand and its H-H separation, calculated from these data, are 0.56(2) kcal/mol and 0.94 Å, respectively. These values indicate that pi-back-donation from the Tp(Me)()2RhH(2) fragment to H(2) is relatively weak and/or the interaction between the coordinated dihydrogen molecule and the two cis-hydride ligands significantly lowers the barrier for H(2) rotation.

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Section: Introductionsupporting

confidence: 82%

Section: Introductionmentioning

confidence: 99%

Nature of the Rh−H₂ Bond in a Dihydrogen Complex Stabilized Only by Nitrogen Donors. Inelastic Neutron Scattering Study of Tp^Me^₂RhH₂(η²-H₂) (Tp^Me^₂ = Hydrotris(3,5-dimethylpyrazolyl)borate)

et al. 1996

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“…The aforementioned cis effect must lead to a weakening of the H 2 bond and to the consequent formation of a nascent bond between the hydride and the central hydrogen of the H 2 molecule. Covalent and an electrostatic mechanisms have been proposed to explain this effect.…”

Section: Resultsmentioning

confidence: 99%

Experimental and Computational Evidence for the Participation of Nonclassical Dihydrogen Species in Proton Transfer Processes on Ru–Arene Complexes with Uncoordinated N Centers. Efficient Catalytic Deuterium Labeling of H₂ with CD₃OD

et al. 2012

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The protonation with Brønsted acids HB (HBF 4 and CF 3 CO 2 H) of [RuH 2 (arene)(PPh 2 Het)] derivatives (PPh 2 Het = dpim, Het = 2-N-methylimidazolyl; PPh 2 Het = PPh 2 py, Het = 2-pyridyl) that contain uncoordinated N atoms has been analyzed experimentally by NMR spectroscopy and through computational studies. Initially, at low temperature, the uncoordinated N atoms of the phosphine are protonated and a proton−hydride exchange is observed by 1 H NMR spectroscopy. The proton transfer leads to the corresponding cationic trihydride intermediates, which exhibit a dual character of classical and nonclassical hydrides, with the nonclassical species being more stable, especially when Het = 2-pyridyl. In fact, the release of H 2 and the formation of the respective monohydride complexes [RuH(arene)(κ 2 -N,P-PPh 2 Het)]B was observed at room temperature. The participation of the uncoordinated N center in the proton transfer process in the stabilization of RuH(H 2 ) + with respect to RuH 3 + species and in the hydride−dihydrogen exchange (cis effect) are discussed. Calculations on the complex [RuH 3 (p-cymene)(PPh 3 )] + have also been carried out for the sake of comparison. A dual character was also found, but in this case the classical species is more stable. H/D exchange of the hydride ligands of the dihydride complexes, using CD 3 OD as the deuterium source, has been studied. The very rapid deuterium labeling of H 2 , catalyzed by the aforementioned dihydrides, has been observed. The known compound [RuH 2 (p-cymene)(PPh 3 )] is also active in this labeling process, and the possible mechanism for both the H/D exchange and the deuterium labeling of H 2 is discussed in light of theoretical studies.

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“…On the basis of the spectroscopic and structural data, and analogy to (H 4 - iPr CNC)FeH 2 (N 2 ) 2 , (H 4 - iPr CNC)FeH 4 is best formulated as an iron(II) complex with classical trans -hydride ligands and a formally L-type η 2 -H 2 ligand completing the coordination sphere . The symmetry observed by NMR spectroscopy coupled with the T 1 (min) data suggests that this view is an oversimplification, as all four hydride ligands are rapidly exchanging in solution, a behavior similar to that reported for (EtPh 2 P) 3 FeH 2 (η 2 -H 2 ) and consistent with the “cis-effect” in metal dihydride–dihydrogen complexes …”

mentioning

confidence: 99%

Synthesis of Iron Hydride Complexes Relevant to Hydrogen Isotope Exchange in Pharmaceuticals

Darmon

Semproni

et al. 2017

Organometallics

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Addition of H 2 gas to the bis(arylimidazolin-2-ylidene)pyridine iron bis(dinitrogen) complex (H 4 -iPr CNC)Fe(N 2 ) 2 resulted in facile oxidative addition of the H−H bond to yield a mixture of (H 4 -iPr CNC)FeH 4 and trans-(H 4 -iPr CNC)FeH 2 (N 2 ), depending on the partial pressures of H 2 and N 2 . Both iron hydride complexes were characterized by X-ray diffraction and proved relevant to the catalytic hydrogen isotope exchange of arene C(sp 2 )−H bonds. Activation of the benzene-d 6 solvent at ambient temperature produced deuterated isotologues of both compounds that exhibit large isotopic perturbation of resonances in the hydride signals.

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Influence of a cis hydride on a coordinated molecular hydrogen ligand cis hydride, Ab initio calculations

Cited by 26 publications

References 0 publications

Nature of the Rh−H₂ Bond in a Dihydrogen Complex Stabilized Only by Nitrogen Donors. Inelastic Neutron Scattering Study of Tp^Me^₂RhH₂(η²-H₂) (Tp^Me^₂ = Hydrotris(3,5-dimethylpyrazolyl)borate)

Nature of the Rh−H₂ Bond in a Dihydrogen Complex Stabilized Only by Nitrogen Donors. Inelastic Neutron Scattering Study of Tp^Me^₂RhH₂(η²-H₂) (Tp^Me^₂ = Hydrotris(3,5-dimethylpyrazolyl)borate)

Experimental and Computational Evidence for the Participation of Nonclassical Dihydrogen Species in Proton Transfer Processes on Ru–Arene Complexes with Uncoordinated N Centers. Efficient Catalytic Deuterium Labeling of H₂ with CD₃OD

Synthesis of Iron Hydride Complexes Relevant to Hydrogen Isotope Exchange in Pharmaceuticals

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Influence of a cis hydride on a coordinated molecular hydrogen ligand cis hydride, Ab initio calculations

Cited by 26 publications

References 0 publications

Nature of the Rh−H2 Bond in a Dihydrogen Complex Stabilized Only by Nitrogen Donors. Inelastic Neutron Scattering Study of TpMe2RhH2(η2-H2) (TpMe2 = Hydrotris(3,5-dimethylpyrazolyl)borate)

Nature of the Rh−H2 Bond in a Dihydrogen Complex Stabilized Only by Nitrogen Donors. Inelastic Neutron Scattering Study of TpMe2RhH2(η2-H2) (TpMe2 = Hydrotris(3,5-dimethylpyrazolyl)borate)

Experimental and Computational Evidence for the Participation of Nonclassical Dihydrogen Species in Proton Transfer Processes on Ru–Arene Complexes with Uncoordinated N Centers. Efficient Catalytic Deuterium Labeling of H2 with CD3OD

Synthesis of Iron Hydride Complexes Relevant to Hydrogen Isotope Exchange in Pharmaceuticals

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Nature of the Rh−H₂ Bond in a Dihydrogen Complex Stabilized Only by Nitrogen Donors. Inelastic Neutron Scattering Study of Tp^Me^₂RhH₂(η²-H₂) (Tp^Me^₂ = Hydrotris(3,5-dimethylpyrazolyl)borate)

Nature of the Rh−H₂ Bond in a Dihydrogen Complex Stabilized Only by Nitrogen Donors. Inelastic Neutron Scattering Study of Tp^Me^₂RhH₂(η²-H₂) (Tp^Me^₂ = Hydrotris(3,5-dimethylpyrazolyl)borate)

Experimental and Computational Evidence for the Participation of Nonclassical Dihydrogen Species in Proton Transfer Processes on Ru–Arene Complexes with Uncoordinated N Centers. Efficient Catalytic Deuterium Labeling of H₂ with CD₃OD