Preparation and characterization of mono-cyclopentadienylvanadium dihalide bis-phosphine complexes; crystal structure of (η5-C5H5)VCL2(PMe3)2

Nieman, J.; Teuben, Jan H.; Huffman, John C.; Caulton, Kenneth G.

doi:10.1016/0022-328x(83)87022-3

Cited by 60 publications

(39 citation statements)

References 34 publications

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“…This product, however, is unstable at room temperature and decomposes into the known paramagnetic compound [34] whose identity was established by X-ray diffraction analysis.…”

mentioning

confidence: 98%

Non‐Innocent Behaviour of Imido Ligands in the Reactions of Silanes with Half‐Sandwich Imido Complexes of Nb and V: A Silane/Imido Coupling Route to Compounds with Nonclassical SiH Interactions

Ignatov¹,

Rees

Merkoulov

et al. 2007

Chemistry A European J

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Reactions of imido complexes [M(Cp)(=NR')(PR''3)2] (M=V, Nb) with silanes afford a plethora of products, depending on the nature of the metal, substitution at silicon and nitrogen and the steric properties of the phosphine. The main products are [M(Cp)(=NR')(PR3)(H)(SiRnCl3-n)] (M=V, Nb; R'=2,6-diisopropylphenyl (Ar), 2,6-dimethylphenyl (Ar')), [Nb(Cp)(=NR')(PR''3)(H)(SiPhR2)] (R2=MeH, H2), [Nb(Cp)(==NR')(PR''3)(Cl)(SiHRnCl2-n)] and [Nb(Cp)(eta 3-N(R)SiR2--H...)(PR''3)(Cl)]. Complexes with the smaller Ar' substituent at nitrogen react faster, as do more acidic silanes. Bulkier groups at silicon and phosphorus slow down the reaction substantially. Kinetic NMR experiments supported by DFT calculations reveal an associative mechanism going via an intermediate N-silane adduct [Nb(Cp){=N(-->SiHClR2)R'}(PR''3)2] bearing a penta-coordinate silicon centre, which then rearranges into the final products through a Si--H or Si--Cl bond activation process. DFT calculations show that this imido-silane adduct is additionally stabilized by a Si--HM agostic interaction. Si--H activation is kinetically preferred even when Si--Cl activation affords thermodynamically more stable products. The niobium complexes [NbCp(=NAr)(PMe3)(H)(SiR2Cl)] (R=Ph, Cl) are classical according to X-ray studies, but DFT calculations suggest the presence of interligand hypervalent interactions (IHI) in the model complex [Nb(Cp) (==NMe)(PMe3)(H)(SiMe2Cl)]. The extent of Si--H activation in the beta-Si--HM agostic complexes [Cp{eta 3-N(R')SiR2--H}M(PR''3)(Cl)] (R''=PMe3, PMe2Ph) primarily depends on the identity of the ligand trans to the Si--H bond. A trans phosphine leads to a stronger Si--H bond, manifested by a larger J(Si--H) coupling constant. The Si--H activation diminishes slightly when a less basic phosphine is employed, consistent with decreased back-donation from the metal.

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“…This product, however, is unstable at room temperature and decomposes into the known paramagnetic compound [34] whose identity was established by X-ray diffraction analysis.…”

mentioning

confidence: 98%

Non‐Innocent Behaviour of Imido Ligands in the Reactions of Silanes with Half‐Sandwich Imido Complexes of Nb and V: A Silane/Imido Coupling Route to Compounds with Nonclassical SiH Interactions

Ignatov¹,

Rees

Merkoulov

et al. 2007

Chemistry A European J

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“…[8] All crystallographically characterised (phosphane)Ti III complexes contain cyclopentadienyl ligands except Ti(BH 4 ) 3 (PMe 3 ) 2 which shows MϪP distances of 2.571(3) and 2.539(3) Å ; [9] All known titaniumϪphosphane distances fall within the range 2.58Ϯ0.07 Å , regardless of oxidation state or coordination number. The PϪTiϪP bond angles in 1 are somewhat compressed [average 82.71 (13)°] compared to those of 2 and 3 although they are similar to those reported for (trimpsi)Ti(CO) 4 , and other chelating phosphanes more generally. [8] The addition of [12]aneP 3 Et 3 to VCl 3 ·3THF gives rise to ([12]aneP 3 Et 3 )VCl 3 (2) which may be isolated as a green crystalline solid in good yield.…”

Section: Introductionmentioning

confidence: 71%

“…This EPR spectrum looks remarkably similar to that reported for VOCl 2 (PEt 3 ) 2 , except for the presence of the weak coupling to the third phosphorus atom, whilst the g and A values are almost identical. [13] The EPR spectrum of 4 was sufficiently resolved, that accurate values of the 31 P superhyperfine tensors could be obtained. The values of P A || ϭ 24.5 G, P A Ќ ϭ 27 G for the two equivalent phosphane moities and P A || ϭ 6 G, P A Ќ ϭ 6.1 G for the third inequivalent P nucleus, were tested by computer simulation ( Figure 3).…”

Section: Epr and Endor Spectroscopymentioning

confidence: 93%

“…2.509(1) Å ]. [13] Although there is no significant difference in the VϪP distances between 2 and complexes of monodentate phosphanes, the five-coordinate complexes are coordinatively unsaturated which presumably contributes to their much greater sensitivity to air and moisture. The preferential oxidation of the metal in 2 also suggests that the MϪP bond is relatively inert.…”

Section: Introductionmentioning

confidence: 99%

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Early Transition Metal Complexes of Triphosphorus Macrocycles

Baker

Davies

Edwards

et al. 2002

Eur. J. Inorg. Chem.

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The reactions of 1,5,9-triethyl-1,5,9-triphosphacyclododecane, [12]aneP 3 Et 3 , with first-row transition metal halides MCl 3 [M = Ti (1), V (2), and Cr (3)] or their THF adducts are reported. The oxidation of 2 gives the complex ([12]aneP 3 Et 3 )-V(O)Cl 2 (4). This is the first example of a phosphane ligand that is trans to a vanadyl moiety. Also reported are V III (5) and Cr III (6) complexes of the pendant ether macrocycles [12]aneP 3 (C 2 H 4 OEt) 3 and 12[ane]P 3 (C 3 H 6 OMe) 3 respectively. The complexes 1−6 have been characterised crystallographically and represent a rare class of phosphane com-

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“…It has been reported that PPh 3 and PCy 3 reacted with VCl 3 to give dimers, i.e., [VCl 3 (PR 3 [29]. Mononuclear complexes with a coordination number of 5 were instead obtained by reacting VCl 3 ·3THF with PMePh 2 , PEt 2 Ph, and PR 3 (R = Me, Et); with a coordination number of 6 [i.e., VCl 3 (P n Pr) 3 and VCl 3 (PR 2 Ph) 3 (R = Me, n Pr)] by reacting VCl 3 ·3THF with P n Pr 3 , PMe 2 Ph and P n Pr 2 Ph [26,28]. With other aliphatic phosphines, only intractable oils were obtained likely due to a reduction-hydrolysis process occurring during the reaction and subsequent workup [32].…”

Section: Resultsmentioning

confidence: 99%

Synthesis, Structure and 1,3-Butadiene Polymerization Behavior of Vanadium(III) Phosphine Complexes

et al. 2017

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A series of vanadium(III) complexes bearing monodentate tertiary phosphine ligands of the type VCl 3 (PR n Ph 3-n ) 2 (n = 0 (1a); n = 1 and R = Me (1b), Et (1c), i Pr (1d), Cy (1e); n = 2 and R = Me (1f), Et (1g), Cy (1h)), and VCl 3 (PR 3 ) 2 (R = Cyp (2a), Cy (2b), n Pr (2c), t Bu (2d)) were synthesized and characterized. In the case of 1c, 1g and 2a single crystals were also obtained and their molecular structures were determined. All the complexes were used, in combination with methylaluminoxane (sMAO) or AlMe 3 -free MAO (dMAO), for the polymerization of 1,3-butadiene, exhibiting rather good activity and giving polymers with different microstructure depending on the nature of the phosphine ligand and the type of co-catalyst employed.

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Preparation and characterization of mono-cyclopentadienylvanadium dihalide bis-phosphine complexes; crystal structure of (η5-C5H5)VCL2(PMe3)2

Cited by 60 publications

References 34 publications

Non‐Innocent Behaviour of Imido Ligands in the Reactions of Silanes with Half‐Sandwich Imido Complexes of Nb and V: A Silane/Imido Coupling Route to Compounds with Nonclassical SiH Interactions

Non‐Innocent Behaviour of Imido Ligands in the Reactions of Silanes with Half‐Sandwich Imido Complexes of Nb and V: A Silane/Imido Coupling Route to Compounds with Nonclassical SiH Interactions

Early Transition Metal Complexes of Triphosphorus Macrocycles

Synthesis, Structure and 1,3-Butadiene Polymerization Behavior of Vanadium(III) Phosphine Complexes

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