Dinitrosyl vanadium complexes

Herberhold, Max; Trampisch, Herbert

doi:10.1016/s0020-1693(00)82793-0

Cited by 18 publications

(7 citation statements)

References 13 publications

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“…Previous efforts to obtain the tantalum analogue of the well-known V(CO) 5 NO, or substituted versions thereof, involved the reactions of [Ta(CO) 6 ] - with 1 equiv of a [NO] + salt, in the absence or presence of appropriate donors and, unlike related reactions with [V(CO) 6 ] - , did not lead to the isolation of any well-defined metal nitrosyls . However, due to the robust character of several vanadium dinitrosyl complexes, , including cis -[V(CNtBu) 4 (NO) 2 ] + , the only previously known cationic isocyanide group 5 complex of this type, it was decided to examine corresponding reactions of [M(CO) 6 ] - , M = Nb, Ta, with 2 equiv of [NO] + . In this article, only the results with CNXyl are reported.…”

Section: Resultsmentioning

confidence: 99%

Homoleptic Isocyanidemetalates of 4d- and 5d-Transition Metals: [Nb(CNXyl)₆]^-, [Ta(CNXyl)₆]^-, and Derivatives Thereof¹

et al. 2007

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Treatment of [M(CO)(6)](-), M = Nb, Ta, with Ag(+), I(2) or NO(+) in the presence of CNXyl provided [M(CNXyl)(7)](+), M(CNXyl)(6)I, or cis-[M(CNXyl)(4)(NO)(2)](+), which are isocyanide analogues of the unknown carbonyl complexes [M(CO)(7)](+), M(CO)(6)I, or cis-[M(CO)(4)(NO)(2)](+), respectively. Reduction of M(CNXyl)(6)I by cesium graphite gave the respective Cs[M(CNXyl)(6)], which have been structurally characterized and represent the first isolable homoleptic isocyanidemetalates for second or third row transition metals. Nitrosylation of [Ta(CNXyl)(6)](-) affords a rare example of a mononitrosyl tantalum complex, Ta(CNXyl)(5)NO, which is an isocyanide analogue of the unknown Ta(CO)(5)NO. This study emphasizes, inter alia, the remarkable versatility of the CNXyl ligand compared to CO in stabilizing various electronic environments at heavier group 5 metal centers.

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Section: Resultsmentioning

confidence: 99%

Homoleptic Isocyanidemetalates of 4d- and 5d-Transition Metals: [Nb(CNXyl)₆]^-, [Ta(CNXyl)₆]^-, and Derivatives Thereof¹

et al. 2007

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“…No other data on the otherwise elusive species [V(CN t Bu) 6 ] +/0 are available. Complexes cis- [V(NO) 2 (CNR) 4 ] + ,12a CpV(NO) 2 (CNR),12b VX(NO) 2 (CNR) 3 ,12c and [V(CO) 5 (CNR)] - represent the only examples of subvalent vanadium isocyanides. On the basis of usual conventions, the above nitrosyl−isocyanide compounds are formally classified as derivatives of V(1−).…”

Section: Introductionmentioning

confidence: 99%

“…However, as evidenced by IR data in the ν CN region, the CNR ligands in these complexes are not much different electronically from those in the V(2+) compounds. Indeed, the C−N stretching bands of, for example, [V(NO) 2 (CN t Bu) 4 ] + occur at 2199 and 2183 cm -1 ,12a while [V(CN t Bu) 6 ] 2+ absorbs at 2190 cm -1 8a…”

Section: Introductionmentioning

confidence: 99%

First Paramagnetic Zerovalent Transition Metal Isocyanides. Syntheses, Structural Characterizations, and Magnetic Properties of Novel Low-Valent Isocyanide Complexes of Vanadium¹

Barybin

Ellis

2000

J. Am. Chem. Soc.

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The first homoleptic paramagnetic transition metal isocyanide, V(CNXyl)6 (2, Xyl = 2,6-dimethylphenyl), can be isolated in high yield by reacting bis(naphthalene)vanadium(0) (1a) or bis(1-methylnaphthalene)vanadium(0) (1b) with 6 equiv of CNXyl in tetrahydrofuran/heptane. Reduction of 2 with excess cesium graphite in THF affords excellent yields of [V(CNXyl)6]- (3) as an unsolvated Cs+ salt, the first homoleptic octahedral isocyanide metalate. Cs3 reacts with 2 equiv of 18-Crown-6 to give [Cs(18-Crown-6)2]3. Anion 3 can also be isolated as a practically insoluble [K(Crypt{2.2.2.})]+ salt by reducing 2 with potassium naphthalenide in the presence of Crypt{2.2.2.}. Complex 3 reduces [Et3NH]Cl to form paramagetic 2. Oxidation of 2 by ferricinium hexafluorophosphate in THF provides nearly quantitative yields of the 16-electron paramagnetic [V(CNXyl)6][PF6] (4[PF6]), analogous to the exceedingly unstable [V(CO)6]+. Interaction of V(CO)6 with excess CNXyl in heptane results in the efficient formation of trans-[V(CO)2(CNXyl)4] (5). Such a substitution reaction is highly unusual for V(CO)6. Oxidation of compound 5 by ferricinium hexafluorophosphate in THF affords homoleptic 4[PF6]. Complexes 2, 3, 4, and 5 were characterized by a variety of spectroscopic methods and X-ray crystallography. Spectroscopic, magnetic, and structural features of these novel electron rich vanadium isocyanides are discussed in detail. The average V−CN bond length increases in the series [V(CNXyl)6]- < V(CNXyl)6 < trans-V(CO)2(CNXyl)4 < [V(CNXyl)6]+. Well-resolved 1H and 13C NMR spectra were obtained for paramagnetic 2 and its chromium congener, [Cr(CNXyl)6]+. The importance of back-bonding in the mechanism of unpaired spin delocalization within 2 was demonstrated. Contrary to the previous prediction for dπ(M)−pπ*(L) unpaired spin delocalization in low-spin d5 octahedral complexes, negative spin appears to be induced on the CNXyl ligands of 2 by means of dπ(V)−pπ*(CNXyl) back-bonding.

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“…Since Hieber's original synthesis of V(CO) 5 (NO), , several mono-, , di-, and trinitrosyl complexes of vanadium have been prepared. However, only very recently have Legzdins and co-workers isolated the first well-defined nitrosyls of niobium and tantalum, namely, M(trimpsi)(NO)(CO) 2 (trimpsi = t BuSi(CH 2 PMe 2 ) 3 , M = Nb, Ta) .…”

mentioning

confidence: 99%

Syntheses and Structural Characterizations ofcis-[M(NO)₂(CNXyl)₄]⁺(M = Nb, Ta; Xyl = 2,6-Me₂C₆H₃). The First Dinitrosyls of Niobium and Tantalum¹

Barybin

Ellis

1999

Organometallics

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Dinitrosyl vanadium complexes

Cited by 18 publications

References 13 publications

Homoleptic Isocyanidemetalates of 4d- and 5d-Transition Metals: [Nb(CNXyl)₆]^-, [Ta(CNXyl)₆]^-, and Derivatives Thereof¹

Homoleptic Isocyanidemetalates of 4d- and 5d-Transition Metals: [Nb(CNXyl)₆]^-, [Ta(CNXyl)₆]^-, and Derivatives Thereof¹

First Paramagnetic Zerovalent Transition Metal Isocyanides. Syntheses, Structural Characterizations, and Magnetic Properties of Novel Low-Valent Isocyanide Complexes of Vanadium¹

Syntheses and Structural Characterizations ofcis-[M(NO)₂(CNXyl)₄]⁺(M = Nb, Ta; Xyl = 2,6-Me₂C₆H₃). The First Dinitrosyls of Niobium and Tantalum¹

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Dinitrosyl vanadium complexes

Cited by 18 publications

References 13 publications

Homoleptic Isocyanidemetalates of 4d- and 5d-Transition Metals: [Nb(CNXyl)6]-, [Ta(CNXyl)6]-, and Derivatives Thereof1

Homoleptic Isocyanidemetalates of 4d- and 5d-Transition Metals: [Nb(CNXyl)6]-, [Ta(CNXyl)6]-, and Derivatives Thereof1

First Paramagnetic Zerovalent Transition Metal Isocyanides. Syntheses, Structural Characterizations, and Magnetic Properties of Novel Low-Valent Isocyanide Complexes of Vanadium1

Syntheses and Structural Characterizations ofcis-[M(NO)2(CNXyl)4]+(M = Nb, Ta; Xyl = 2,6-Me2C6H3). The First Dinitrosyls of Niobium and Tantalum1

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Homoleptic Isocyanidemetalates of 4d- and 5d-Transition Metals: [Nb(CNXyl)₆]^-, [Ta(CNXyl)₆]^-, and Derivatives Thereof¹

Homoleptic Isocyanidemetalates of 4d- and 5d-Transition Metals: [Nb(CNXyl)₆]^-, [Ta(CNXyl)₆]^-, and Derivatives Thereof¹

First Paramagnetic Zerovalent Transition Metal Isocyanides. Syntheses, Structural Characterizations, and Magnetic Properties of Novel Low-Valent Isocyanide Complexes of Vanadium¹

Syntheses and Structural Characterizations ofcis-[M(NO)₂(CNXyl)₄]⁺(M = Nb, Ta; Xyl = 2,6-Me₂C₆H₃). The First Dinitrosyls of Niobium and Tantalum¹