Intramolecular hydrogen transfer from the alkyl substituent of a phosphine ligand to a metal atom upon the irradiation of tungsten phosphine hydride complexes

Pivovarov, A. P.; Ioffe, L.M.; Gak, Yu. V.; Makhaev, V. D.; Borisov, A. P.; Borod'ko, Yu. G.

doi:10.1007/bf00956338

Cited by 3 publications

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“… Photocatalytic reduction of molecular nitrogen to ammonia and hydrazine has been demonstrated with W(H) 4 (dppe) 2 , W(H) 4 (PPh 2 Me) 4 , and W(H) 4 (etp)(PPh 3 ) (etp = PhP(CH 2 CH 2 PPh 2 ) 2 ) as catalysts; light in this case was responsible for the H 2 elimination, which creates a free vacant site for the dinitrogen to coordinate . Studies on W(H) 4 (PRPh 2 ) 4 (R = CD 3 , C 2 D 5 ) also established H 2 loss as the primary photochemical step; the unsaturated species formed underwent intramolecular C–D insertion to form a metal–carbon bond with subsequent HD photoelimination . Finally, the clusters [{(Cp″Y) 4 (μ-H) 7 }(μ-H) 4 MCp*(PMe 3 )] (M = Mo, W, Cp′′ = η 5 -C 5 Me 4 H) were found to undergo PMe 3 loss under UV irradiation …”

Section: Metal Hydride Photochemistry By Transition Metal Groupmentioning

confidence: 82%

“…190 Studies on W(H) 4 (PRPh 2 ) 4 (R = CD 3 , C 2 D 5 ) also established H 2 loss as the primary photochemical step; the unsaturated species formed underwent intramolecular C−D insertion to form a metal−carbon bond with subsequent HD photoelimination. 191 Finally, the clusters [{(Cp″Y) 4 (μ-H) 7 }(μ-H) 4 MCp*(PMe 3 )] (M = Mo, W, Cp′′ = η 5 -C 5 Me 4 H) were found to undergo PMe 3 loss under UV irradiation. 192…”

Section: Group 6 Metalsmentioning

confidence: 99%

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Photochemistry of Transition Metal Hydrides

2016

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Photochemical reactivity associated with metal-hydrogen bonds is widespread among metal hydride complexes and has played a critical part in opening up C-H bond activation. It has been exploited to design different types of photocatalytic reactions and to obtain NMR spectra of dilute solutions with a single pulse of an NMR spectrometer. Because photolysis can be performed on fast time scales and at low temperature, metal-hydride photochemistry has enabled determination of the molecular structure and rates of reaction of highly reactive intermediates. We identify five characteristic photoprocesses of metal monohydride complexes associated with the M-H bond, of which the most widespread are M-H homolysis and R-H reductive elimination. For metal dihydride complexes, the dominant photoprocess is reductive elimination of H2. Dihydrogen complexes typically lose H2 photochemically. The majority of photochemical reactions are likely to be dissociative, but hydride complexes may be designed with equilibrated excited states that undergo different photochemical reactions, including proton transfer or hydride transfer. The photochemical mechanisms of a few reactions have been analyzed by computational methods, including quantum dynamics. A section on specialist methods (time-resolved spectroscopy, matrix isolation, NMR, and computational methods) and a survey of transition metal hydride photochemistry organized by transition metal group complete the Review.

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Section: Metal Hydride Photochemistry By Transition Metal Groupmentioning

confidence: 82%

Section: Group 6 Metalsmentioning

confidence: 99%

Photochemistry of Transition Metal Hydrides

2016

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“…5 Coordinationatly unsaturated species formed during photolysis can also enter intramoleeular reactions of oxidative addition of aryl or alkyl substituents of phosphine ligands. 6 Under irradiation, CO 2 in the coordination sphere of the metal is reduced to formate, which gives formaldehyde or formic acid under the action of an acid (HCI, H:SO4). 7 In this connection, it is of interest to study the mechanism of photoreductive dehydrogenatation of phosphinehydride complexes.…”

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Determination of charge-transfer electron transitions in tungsten tetrahydride complexes stabilized by organophosphorus ligands by X-ray photoelectron and UV absorption spectra

Pivovarov

1997

Russ Chem Bull

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A change in the energy of the long-wave transition in the UV absorption spectra of tetrahydride complexes WH.~L 4 is equal to the change in the energy of the internat 2p-levet of phosphorus. Based on the correlation determined, the electron transitions related to the !ong-wave absorption bands in the UV spectra were assigned to the charge-transfer transitions from the organophosphorus ligand to tungsten.

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Molecular structure of W(PMe3)3H6 in the solid state and in solution

Sattler

Zuzek

Parkin

2014

Inorganica Chimica Acta

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The molecular structure of W(PMe 3) 3 H 6 has been identified by low temperature (-123 ˚C) X-ray diffraction studies as a classical hydride compound, with a tricapped trigonal prismatic geometry in which two of the PMe 3 ligands adopt eclipsed positions on opposite triangular faces of the prism and one PMe 3 ligand caps a rectangular face. The solid state structure is reproduced well by density functional theory geometry optimization calculations on the molecule in the gas phase. NMR spectroscopic studies provide evidence that W(PMe 3) 3 H 6 also exists as a classical hydride compound in solution. For example, the T 1(min) value for the hydride ligands of W(PMe 3) 3 H 6 is 380 ms at 500 MHz and 310 ms at 400 MHz, values that are more in accord with a classical hydride formulation than a nonclassical one. Likewise, the W(PMe 3) 3 H 6-x D x isotopologues (obtained by isotope exchange with either deuterobenzene or deuterotoluene) exhibit upfield (+13 ppb) deuterium secondary isotope effects on the hydride chemical shift, which are also consistent with a classical description.

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Intramolecular hydrogen transfer from the alkyl substituent of a phosphine ligand to a metal atom upon the irradiation of tungsten phosphine hydride complexes

Cited by 3 publications

References 5 publications

Photochemistry of Transition Metal Hydrides

Photochemistry of Transition Metal Hydrides

Determination of charge-transfer electron transitions in tungsten tetrahydride complexes stabilized by organophosphorus ligands by X-ray photoelectron and UV absorption spectra

Molecular structure of W(PMe3)3H6 in the solid state and in solution

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