Hydrazido(2–)-complexes of tungsten-(<scp>V</scp>) and -(<scp>VI</scp>) and a bis(diazenido)-complex of tungsten(<scp>IV</scp>). X-Ray crystal structure of cis-[WCl3(NNH2)(PMe2Ph)2]

Chatt, J.; Fakley, M. E.; Hitchcock, Peter B.; Richards, Raymond L.; Luong-Thi, Ngoc-Tuyet

doi:10.1039/dt9820000345

Cited by 22 publications

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“…The W−Cl bond distances are on the order of 2.34 Å, which is within the expected range for W VI −Cl bonds. The short W−N1 bond distance [1.769(5) Å] and a short bond distance of 1.271(8) Å between N1 and N2 suggest a high degree of delocalization and significant multiple-bond character throughout the W1−N1−N2 unit, which is consistent with other hydrazido complexes of tungsten with multiple chloride ligands such as [W(η 5 -C 5 Me 5 )Cl 3 (NNPh 2 )] [W−N 1.769(2) Å; N−N 1.296(3) Å] and cis -[WCl 3 (NNH 2 )(PMe 2 Ph) 2 ] [W−N 1.752(10) Å; N−N 1.300(17) Å]. This observation can be explained based upon two possible limiting electronic structures, A and B , with representation A being the major contributor.…”

Section: Resultssupporting

confidence: 75%

Synthesis and Characterization of Diorganohydrazido(2–) Tungsten Complexes

et al. 2007

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Diorganohydrazido(2-) complexes of tungsten (L)Cl4W(NNR2) [R2=Me2, Ph2, -(CH2)5-; L=CH3CN, pyridine] were synthesized by reacting the corresponding 1,1-diorganohydrazine with WCl6, followed by reaction with acetonitrile or pyridine. Crystallographic structure determination of (CH3CN)Cl4W(NNMe2) and (CH3CN)Cl4W(NNPh2) allows a comparison of the structural features of the diorganohydrazido(2-) functionality with varying substituents. Mass spectrometry, thermogravimetric analysis, and preliminary chemical vapor deposition experiments were performed to determine the viability of these complexes as single-source precursors for deposition of WNx and WNxCy films.

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Section: Resultssupporting

confidence: 75%

Synthesis and Characterization of Diorganohydrazido(2–) Tungsten Complexes

et al. 2007

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“…The highest in trans influence is the oxide ligand followed by imide ligands, which is not unexpected in view of their good σ-donor power and π-releasing ability . Hydrazides, being good σ-donors and π-releasing ligands, also have a relatively strong trans influence. Lowest in the series is CH 3 CN, entirely in keeping with its overall weakness as a ligand …”

Section: Resultsmentioning

confidence: 99%

Vanadium Complexes of the N(CH₂CH₂S)₃^3-and O(CH₂CH₂S)₂^2-Ligands with Coligands Relevant to Nitrogen Fixation Processes

et al. 2000

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Vanadium(III) and vanadium(V) complexes derived from the tris(2-thiolatoethyl)amine ligand [(NS3)3-] and the bis(2-thiolatoethyl)ether ligand [(OS2)2-] have been synthesized with the aim of investigating the potential of these vanadium sites to bind dinitrogen and activate its reduction. Evidence is presented for the transient existence of (V(NS3)(N2)V(NS3), and a series of mononuclear complexes containing hydrazine, hydrazide, imide, ammine, organic cyanide, and isocyanide ligands has been prepared and the chemistry of these complexes investigated. [V(NS3)O] (1) reacts with an excess of N2H4 to give, probably via the intermediates (V(NS3)(NNH2) (2a) and (V(NS3)(N2)V(NS3) (3), the V(III) adduct [V(NS3)(N2H4)] (4). If 1 is treated with 0.5 mol of N2H4, 0.5 mol of N2 is evolved and green, insoluble [(V(NS3))n] (5) results. Compound 4 is converted by disproportionation to [V(NS3)(NH3)] (6), but 4 does not act as a catalyst for disproportionation of N2H4 nor does it act as a catalyst for its reduction by Zn/HOC6H3Pri2-2,6. Compound 1 reacts with NR1(2)NR2(2) (R1 = H or SiMe3; R2(2) = Me2, MePh, or HPh) to give the hydrazide complexes [V(NS3)(NNR2(2)] (R2(2) = Me2, 2b; R2(2) = MePh, 2c; R2(2) = HPh, 2d), which are not protonated by anhydrous HBr nor are they reduced by Zn/HOC6H3Pri2-2,6. Compound 2b can also be prepared by reaction of [V(NNMe2)(dipp)3] (dipp = OC6H3Pri2-2,6) with NS3H3. N2H4 is displaced quantitatively from 4 by anions to give the salts [NR3(4)][V(NS3)X] (X = Cl, R3 = Et, 7a; X = Cl, R3 = Ph, 7b; X = Br, R3 = Et, 7c; X = N3, R3 = Bu(n), 7d; X = N3, R3 = Et, 7e; X = CN, R3 = Et, 7f). Compound 6 loses NH3 thermally to give 5, which can also be prepared from [VCl3(THF)3] and NS3H3/LiBun. Displacement of NH3 from 6 by ligands L gives the adducts [V(NS3)(L)] (L = MeCN, nu CN 2264 cm-1, 8a; L = ButNC, nu NC 2173 cm-1, 8b; L = C6H11NC, nu NC 2173 cm-1, 8c). Reaction of 4 with N3SiMe3 gives [V(NS3)(NSiMe3)] (9), which is converted to [V(NS3)(NH)] (10) by hydrolysis and to [V(NS3)(NCPh3)] (11) by reaction with ClCPh3. Compound 10 is converted into 1 by [NMe4]OH and to [V(NS3)NLi(THF)2] (12) by LiNPri in THF. A further range of imido complexes [V(NS3)(NR4)] (R4 = C6H4Y-4 where Y = H (13a), OMe (13b), Me (13c), Cl (13d), Br (13e), NO2 (13f); R4 = C6H4Y-3, where Y = OMe (13g); Cl (13h); R4 = C6H3Y2-3,4, where Y = Me (13i); Cl (13j); R4 = C6H11 (13k)) has been prepared by reaction of 1 with R4NCO. The precursor complex [V(OS2)O(dipp)] (14) [OS2(2-) = O(CH2CH2S)2(2-)] has been prepared from [VO(OPri)3], Hdipp, and OS2H2. It reacts with NH2NMe2 to give [V(OS2)(NNMe2)(dipp)] (15) and with N3SiMe3 to give [V(OS2)(NSiMe3)(dipp)] (16). A second oxide precursor, formulated as [V(OS2)1.5O] (17), has also been obtained, and it reacts with SiMe3NHNMe2 to give [V(OS2)(NNMe2)(OSiMe3)] (18). The X-ray crystal structures of the complexes 2b, 2c, 4, 6, 7a, 8a, 9, 10, 13d, 14, 15, 16, and 18 have been determined, and the 51V NMR and other spectroscopic parameters of the complexes are discussed in terms of electronic effects.

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“…These results show that the structure of 20 is similar to that of 19 . Previously it was reported that the hydrazido(2−) complex [WHCl 3 (NNH 2 )(PMePh 2 ) 2 ] was produced by the reaction of 14 with anhydrous HCl in dichloromethane 3 …”

Section: Resultsmentioning

confidence: 99%

Formation of Ammonia in the Reactions of a Tungsten Dinitrogen with Ruthenium Dihydrogen Complexes under Mild Reaction Conditions¹

et al. 2000

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Treatment of cis-[W(N2)2(PMe2Ph)4] (5) with an equilibrium mixture of trans-[RuCl(eta 2-H2)(dppp)2]X (3) with pKa = 4.4 and [RuCl(dppp)2]X (4) [X = PF6, BF4, or OTf; dppp = 1,3-bis(diphenylphosphino)propane] containing 10 equiv of the Ru atom based on tungsten in benzene-dichloroethane at 55 degrees C for 24 h under 1 atm of H2 gave NH3 in 45-55% total yields based on tungsten, together with the formation of trans-[RuHCl(dppp)2] (6). Free NH3 in 9-16% yields was observed in the reaction mixture, and further NH3 in 36-45% yields was released after base distillation. Detailed studies on the reaction of 5 with numerous Ru(eta 2-H2) complexes showed that the yield of NH3 produced critically depended upon the pKa value of the employed Ru(eta 2-H2) complexes. When 5 was treated with 10 equiv of trans-[RuCl(eta 2-H2)(dppe)2]X (8) with pKa = 6.0 [X = PF6, BF4, or OTf; dppe = 1,2-bis(diphenylphosphino)ethane] under 1 atm of H2, NH3 was formed in higher yields (up to 79% total yield) compared with the reaction with an equilibrium mixture of 3 and 4. If the pKa value of a Ru(eta 2-H2) complex was increased up to about 10, the yield of NH3 was remarkably decreased. In these reactions, heterolytic cleavage of H2 seems to occur at the Ru center via nucleophilic attack of the coordinated N2 on the coordinated H2 where a proton (H+) is used for the protonation of the coordinated N2 and a hydride (H-) remains at the Ru atom. Treatment of 5, trans-[W(N2)2(PMePh2)4] (14), or trans-[M(N2)2(dppe)2] [M = Mo (1), W (2)] with Ru(eta 2-H2) complexes at room temperature led to isolation of intermediate hydrazido(2-) complexes such as trans-[W(OTf)(NNH2)(PMe2Ph)4]OTf (19), trans-[W(OTf)(NNH2)(PMePh2)4]OTf (20), and trans-[WX(NNH2)(dppe)2]+ [X = OTf (15), F (16)]. The molecular structure of 19 was determined by X-ray analysis. Further ruthenium-assisted protonation of hydrazido(2-) intermediates such as 19 with H2 at 55 degrees C was considered to result in the formation of NH3, concurrent with the generation of W(VI) species. All of the electrons required for the reduction of N2 are provided by the zerovalent tungsten.

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Hydrazido(2–)-complexes of tungsten-(V) and -(VI) and a bis(diazenido)-complex of tungsten(IV). X-Ray crystal structure of cis-[WCl₃(NNH₂)(PMe₂Ph)₂]

Abstract: 1982 345 Hydrazido(2-)-complexes of Tungsten-(v) and -(vI) and a Bis(diazenid0)complex of Tungsten(iv). X-Ray Crystal Structure of cis-[WCI3(NNH2)-(PMesPh),l t

Cited by 22 publications

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Synthesis and Characterization of Diorganohydrazido(2–) Tungsten Complexes

Synthesis and Characterization of Diorganohydrazido(2–) Tungsten Complexes

Vanadium Complexes of the N(CH₂CH₂S)₃^3-and O(CH₂CH₂S)₂^2-Ligands with Coligands Relevant to Nitrogen Fixation Processes

Formation of Ammonia in the Reactions of a Tungsten Dinitrogen with Ruthenium Dihydrogen Complexes under Mild Reaction Conditions¹

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Hydrazido(2–)-complexes of tungsten-(V) and -(VI) and a bis(diazenido)-complex of tungsten(IV). X-Ray crystal structure of cis-[WCl3(NNH2)(PMe2Ph)2]

Abstract: 1982 345 Hydrazido(2-)-complexes of Tungsten-(v) and -(vI) and a Bis(diazenid0)complex of Tungsten(iv). X-Ray Crystal Structure of cis-[WCI3(NNH2)-(PMesPh),l t

Cited by 22 publications

References 0 publications

Synthesis and Characterization of Diorganohydrazido(2–) Tungsten Complexes

Synthesis and Characterization of Diorganohydrazido(2–) Tungsten Complexes

Vanadium Complexes of the N(CH2CH2S)33-and O(CH2CH2S)22-Ligands with Coligands Relevant to Nitrogen Fixation Processes

Formation of Ammonia in the Reactions of a Tungsten Dinitrogen with Ruthenium Dihydrogen Complexes under Mild Reaction Conditions1

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Hydrazido(2–)-complexes of tungsten-(V) and -(VI) and a bis(diazenido)-complex of tungsten(IV). X-Ray crystal structure of cis-[WCl₃(NNH₂)(PMe₂Ph)₂]

Vanadium Complexes of the N(CH₂CH₂S)₃^3-and O(CH₂CH₂S)₂^2-Ligands with Coligands Relevant to Nitrogen Fixation Processes

Formation of Ammonia in the Reactions of a Tungsten Dinitrogen with Ruthenium Dihydrogen Complexes under Mild Reaction Conditions¹