Protonation of bis[1,2-bis(diethylphosphino)ethane]bis(dinitrogen)-molybdenum and -tungsten with fluoroboric acid–diethyl ether (1/1) in benzene; crystal and molecular structure of bis[1,2- bis(diethylphosphino)ethane]fluoro[hydrazido(2–)]tungsten tetrafluoroborate

Barclay, J. Elaine; Hills, Adrian; Hughes, David L.; Leigh, G. J.; Macdonald, Colin; Bakar, Mohamad Abu; Ali, Hapipah Mohd

doi:10.1039/dt9900002503

Cited by 29 publications

(24 citation statements)

References 11 publications

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“…Using tungsten and molybdenum diphosphine complexes, he unravelled the first stages of dinitrogen protonation [19] and we showed later [20] that a third proton could be persuaded to attack the exo-nitrogen, a finding that was confirmed also by others (Fig. 3).…”

supporting

confidence: 59%

A personal account of some dinitrogen and organometallic chemistry research at the University of Sussex

Leigh

2004

Journal of Organometallic Chemistry

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supporting

confidence: 59%

A personal account of some dinitrogen and organometallic chemistry research at the University of Sussex

Leigh

2004

Journal of Organometallic Chemistry

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“…Although imido complexes of tungsten and molybdenum have been synthesized by other methods, − the isolation and characterization of the ethylimido complex 4 represents the first example of the preparation of an imido complex from the protic reduction of a nitrile ligand. The analogous β-protonation of isoelectronic ligands (dinitrogen, isonitriles, and acetylides 4 ) at metal centers has been well-established, and the preparation of complex 4 effectively completes this series.…”

Section: Resultsmentioning

confidence: 98%

Reduction of a Coordinated Acetonitrile Ligand: Synthesis of an Ethylimido Complex of Tungsten

1998

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Treatment of the dinitrogen complex W(N2)2(dppe)2 (1; dppe = 1,2-bis(diphenylphosphino)ethane) with trifluoromethanesulfonic acid yields the novel hydrazido complex [W(N2H2)(OTf)(dppe)2]+[OTf]- (2; OTf = CF3SO3 -). The triflato ligand is readily displaced by other ligands and coordinating solvents. The triflato complex 2 yields the complex [W(N2H2)(NCCH3)(dppe)2]2+ (5), when it is dissolved in acetonitrile, and 5 is readily deprotonated by a variety of bases to give the acetonitrile−dinitrogen complex W(N2)(NCCH3)(dppe)2 (3). Complex 3 is protonated at the β-carbon by tetrafluoroboric acid, resulting in the reduction of the coordinated nitrile to give the novel imido complex [WF(NCH2CH3)(dppe)2]+[BF4]- (4). The X-ray crystal structure of the imido complex 4 reveals an effectively linear W−N−C bond (171.8°) in the imido ligand with a W−N bond length of 1.741(4) Å.

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“…This bonding mode has also been put forward by extended-Hückel calculations of Plass . As a consequence of the primary end-on bonding mode of dinitrogen, protonation to NH 3 would proceed initially via intermediates NNH x which are well known from simple mononuclear Mo/W−phosphine complexes . In the small-molecule systems, the asymmetric coordination of N 2 causes a negative partial charge at the β-nitrogen.…”

Section: Introductionmentioning

confidence: 91%

The Reduction Pathway of End-on Coordinated Dinitrogen. II. Electronic Structure and Reactivity of Mo/W−N₂, −NNH, and −NNH₂Complexes

Lehnert

Tuczek

1999

Inorg. Chem.

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DFT calculations (B3LYP/LanL2DZ) of simplified models of [Mo(N(2))(2)(dppe)(2)] and the two protonated derivatives [MoF(NNH)(dppe)(2)] and [MoF(NNH(2))(dppe)(2)](+) (dppe = 1,2-bis(diphenylphosphino)ethane) provide quantitative insight into the reduction and protonation of dinitrogen bound end-on terminally to transition metals. This "asymmetric" reduction pathway is characterized by a stepwise increase of covalency and a concomitant charge donation from the metal center during each protonation reaction. The major part of metal-to-ligand charge transfer occurs after the first protonation leading to coordinated diazenido(-). In contrast, addition of the second proton is accompanied by a minor change of covalency leading to a NNH(2) species which is neutral and hence corresponds to coordinated isodiazene. UV-vis data of Mo and corresponding W complexes support the calculated energy level schemes. Moreover, calculated vibrational frequencies and force constants show good agreement with experimental values determined in Part I of this series (Lehnert, N.; Tuczek, F. Inorg. Chem. 1999, 38, 1659-1670). The implications of the electronic structure description obtained for the above model complexes with respect to the reduction and protonation of dinitrogen in small-molecule systems and nitrogenase are discussed.

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Protonation of bis[1,2-bis(diethylphosphino)ethane]bis(dinitrogen)-molybdenum and -tungsten with fluoroboric acid–diethyl ether (1/1) in benzene; crystal and molecular structure of bis[1,2- bis(diethylphosphino)ethane]fluoro[hydrazido(2–)]tungsten tetrafluoroborate

Abstract: Protonat ion ofBis[ 1,2-bis( diethyl phosphino)ethane] bis( din it rogen)molybdenum and -tungsten with Fluoroboric Acid-Diethyl Ether (1 / I ) in Benzene; Crystal and Molecular Structure of Bis[l,2bis( diet hyl phosp hino)ethane] f luoro [ hydrazido( 2-)]tungsten Tetraf luoro borate t J.

Cited by 29 publications

References 11 publications

A personal account of some dinitrogen and organometallic chemistry research at the University of Sussex

A personal account of some dinitrogen and organometallic chemistry research at the University of Sussex

Reduction of a Coordinated Acetonitrile Ligand: Synthesis of an Ethylimido Complex of Tungsten

The Reduction Pathway of End-on Coordinated Dinitrogen. II. Electronic Structure and Reactivity of Mo/W−N₂, −NNH, and −NNH₂Complexes

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Protonation of bis[1,2-bis(diethylphosphino)ethane]bis(dinitrogen)-molybdenum and -tungsten with fluoroboric acid–diethyl ether (1/1) in benzene; crystal and molecular structure of bis[1,2- bis(diethylphosphino)ethane]fluoro[hydrazido(2–)]tungsten tetrafluoroborate

Abstract: Protonat ion ofBis[ 1,2-bis( diethyl phosphino)ethane] bis( din it rogen)molybdenum and -tungsten with Fluoroboric Acid-Diethyl Ether (1 / I ) in Benzene; Crystal and Molecular Structure of Bis[l,2bis( diet hyl phosp hino)ethane] f luoro [ hydrazido( 2-)]tungsten Tetraf luoro borate t J.

Cited by 29 publications

References 11 publications

A personal account of some dinitrogen and organometallic chemistry research at the University of Sussex

A personal account of some dinitrogen and organometallic chemistry research at the University of Sussex

Reduction of a Coordinated Acetonitrile Ligand: Synthesis of an Ethylimido Complex of Tungsten

The Reduction Pathway of End-on Coordinated Dinitrogen. II. Electronic Structure and Reactivity of Mo/W−N2, −NNH, and −NNH2Complexes

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The Reduction Pathway of End-on Coordinated Dinitrogen. II. Electronic Structure and Reactivity of Mo/W−N₂, −NNH, and −NNH₂Complexes