PC Bond Cleavage of (silox)3NbPMe3 (silox = tBu3SiO) under Dihydrogen Leads to (silox)3NbCH2, (silox)3NbPH or (silox)3NbP(H)Nb(silox)3, and CH4

Hirsekorn, Kurt F.; Veige, and Adam S.; Wolczanski, Peter T.

doi:10.1021/ja057747f

Cited by 51 publications

(60 citation statements)

References 37 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…The reaction of complex [Nb(silox) 3 (PMe 3 )] (silox = OSi t Bu 3 ) with a 1:1 mixture of N 2 and H 2 (pH 2 ~ pN 2 = 175 Torr), in a NMR tube under ambient light, led to the precipitation of a brick-red insoluble solid (43% yield) [72]. The product was then identified by an X-ray study as the phosphinidene complex [Nb 2 (silox) 6 (μ-PH)].…”

Section: Scheme 37mentioning

confidence: 99%

Phosphinidene-bridged binuclear complexes

Garcı́a

García‐Vivó

Ramos

et al. 2017

Coordination Chemistry Reviews

View full text Add to dashboard Cite

This article contains a comprehensive review of the work carried out within the last three decades on the synthesis, structural studies and reactivity of the binuclear complexes of transition and lanthanide elements bearing bridging phosphinidene (PR) ligands. The latter are grouped into three different classes according to their geometry and electronic distribution: pyramidal, symmetric planar trigonal and asymmetric planar trigonal. Different reactivity patterns can be then outlined for each of these classes of metal complexes, which differ in many ways from those characterizing the extensively studied chemical behaviour of mononuclear phosphinidene complexes.

show abstract

Section: Scheme 37mentioning

confidence: 99%

Phosphinidene-bridged binuclear complexes

Garcı́a

García‐Vivó

Ramos

et al. 2017

Coordination Chemistry Reviews

View full text Add to dashboard Cite

show abstract

“…

…”

mentioning

confidence: 99%

A Transient V^III–Alkylidene Complex: Oxidation Chemistry Including the Activation of N₂ to Afford a Highly Porous Honeycomb‐Like Framework

et al. 2008

View full text Add to dashboard Cite

Terminal vanadium alkylidenes [1][2][3][4] still constitute a rare class of complexes, and this type of functional group, when combined with this metal, has been far less explored than its heavier congeners niobium [5,6] and tantalum. [6] Part of this limitation revolves around the ability of vanadium to populate low-valent oxidation states, especially the + 3 state. As a result, alkylation reactions stemming from the high-valent metal complex often lead to reduction as opposed to the more prototypical transmetalation/a-hydrogen abstraction processes encountered in Nb V and Ta V alkylidenes.[6] Out of the few terminal vanadium alkylidene complexes known (e.g. V III ,[1] V IV , [3] and V V[4] ), only the high-valent system appears to be highly reactive for ring-opening metathesis polymerization (ROMP).[4] Therefore, an entry to the V V alkylidene group directly from a V III precursor would represent an attractive synthetic strategy for this metal given the vast quantity of low-valent vanadium halide precursors available. In general, heat, photolysis, Lewis bases, or Brønsted bases can incite a-hydrogen abstraction to form Schrock-like MÀC multiple bonds. [6,7] More recently, a one-electron oxidation step has been also shown to promote a-hydrogen abstraction. [7] When the metal is in a highoxidation state, powerful Lewis acids such as Al(CH 3 ) 3 can also instigate a-hydrogen abstraction as well as trap the MÀC multiple bond.[ [8][9][10] Although a handful of vanadium alkylidenes have been generated by treatment of a bis-alkyl precursor with PR 3 , [1] the concept of using two-electron oxidants to promote a-hydrogen abstraction, to the extent of providing a facile entry to the V V alkylidene unit, has not been realized.Herein we demonstrate that p acids or two-electron oxidants can ultimately lead to a-hydrogen abstraction when the metal in question is a low-valent V III bis-neopentyl species. As a result, a transient, four-coordinate V III neopentylidene can be generated and trapped with a series of two-electron oxidants to afford a family of V V alkylidenes. In the case where the p acid promoting the a-hydrogen abstraction is sterically crowded, N 2 becomes the substrate of choice to afford the first vanadium bridging end-on dinitrogenalkylidene species. The solid state packing diagram for this complex displays a highly "porous" honeycomb-like framework along the activated N 2 unit. During the course of our investigation, we also discovered that the elusive V III alkylidene generated in these set of reactions can be trapped with a chelate p acid such as 2,2'-bipyridine (bpy).When the bis-alkyl precursor, readily prepared from a one-pot reaction of Li(PNP) and [VCl 3 (thf) 3 ] followed by alkylation with the appropriate stoichiometry of LiCH 2 tBu, [11] was treated with N 2 CPh 2 in diethyl ether, a gradual reaction ensued over a period of 12 h to afford the V V alkylidenediphenylmethylene hydrazido [12] complex [(PNP)V( = CHtBu)(N 2 CPh 2 )] (2) in 62 % yield after workup of the reaction mixture (Scheme 1). Li...

show abstract

“…There is ample precedent for CH bond activation by W(II) in this manner. [19][20][21][22] (silox) 3 The reduction of 15 with 2 equiv of Na/Hg in the presence of 3 equiv of PMe 3 in diethyl ether generated the purple W(IV) (silox) 2 WCl 2 (PMe 3 ) (16) complex in 72% yield, as shown in eq 4. The structure of diamagnetic 16 is assumed to be analogous to its Mo congener (12) and its spectral parameters are listed in Table 1.…”

Section: Synthesis Of (Silox) 2 Mocl 2 (Pme 3 ) (12)mentioning

confidence: 99%

Four-Coordinate Mo(II) as (silox)₂Mo(PMe₃)₂and Its W(IV) Congener (silox)₂HW(η²-CH₂PMe₂)(PMe₃) (silox =^tBu₃SiO)

Kuiper¹,

Wolczanski²,

Lobkovsky³

et al. 2008

Inorg. Chem.

Self Cite

View full text Add to dashboard Cite

The reduction of [( t Bu3SiO)2MoCl]2 (2 2) provided the cyclometalated derivative, (silox)2HMoMo(κ-O,C-OSi t Bu2CMe2CH2)(silox) (3), and alkylation of 2 2 with MeMgBr afforded [( t Bu3SiO)2MoCH3]2 (4 2). The hydrogenation of 4 2 was ineffective, but the reduction of 2 2 under H2 generated [( t Bu3SiO)2MoH]2 (5 2), and the addition of 2-butyne to 3 gave [(silox)2Mo]2(μ:η2η2-C2Me2) (6), thereby implicating the existence of [(silox)2Mo]2 (1 2). The addition of (silox)H to Mo(NMe2)4 led to (silox)2Mo(NMe2)2 (7), but further elaboration of the core proved ineffective. The silanolysis of MoCl5 afforded (silox)2MoCl4 (8) and (silox)3MoCl3 (9) as a mixture from which pure 8 could be isolated, and the addition of THF or PMe3 resulted in derivatives of 9 as (silox)2Cl3MoL (L = THF, 10; PMe3, 11). Reductions of 11 and (silox)2WCl4 (15) in the presence of excess PMe3 provided (silox)2Cl2MPMe3 (M = Mo, 12; W, 16) or (silox)2HW(η2-CH2PMe2)PMe3 (14). While “(silox)2W(PMe3)2” was unstable with respect to W(IV) as 14, a reduction of 12 led to the stable Mo(II) diphosphine, (silox)2Mo(PMe3)2 (17). X-ray crystal structures of 10 (pseudo-O h ), 12 (square pyramidal), and 14 and 17 (distorted T d ) are reported. Calculations address the diamagnetism of 12 and 16, and the distortion of 17 and its stability to cyclometalation in contrast to 14.

show abstract

PC Bond Cleavage of (silox)₃NbPMe₃ (silox = ^tBu₃SiO) under Dihydrogen Leads to (silox)₃NbCH₂, (silox)₃NbPH or (silox)₃NbP(H)Nb(silox)₃, and CH₄

Cited by 51 publications

References 37 publications

Phosphinidene-bridged binuclear complexes

Phosphinidene-bridged binuclear complexes

A Transient V^III–Alkylidene Complex: Oxidation Chemistry Including the Activation of N₂ to Afford a Highly Porous Honeycomb‐Like Framework

Four-Coordinate Mo(II) as (silox)₂Mo(PMe₃)₂and Its W(IV) Congener (silox)₂HW(η²-CH₂PMe₂)(PMe₃) (silox =^tBu₃SiO)

Contact Info

Product

Resources

About

PC Bond Cleavage of (silox)3NbPMe3 (silox = tBu3SiO) under Dihydrogen Leads to (silox)3NbCH2, (silox)3NbPH or (silox)3NbP(H)Nb(silox)3, and CH4

Cited by 51 publications

References 37 publications

Phosphinidene-bridged binuclear complexes

Phosphinidene-bridged binuclear complexes

A Transient VIII–Alkylidene Complex: Oxidation Chemistry Including the Activation of N2 to Afford a Highly Porous Honeycomb‐Like Framework

Four-Coordinate Mo(II) as (silox)2Mo(PMe3)2and Its W(IV) Congener (silox)2HW(η2-CH2PMe2)(PMe3) (silox =tBu3SiO)

Contact Info

Product

Resources

About

PC Bond Cleavage of (silox)₃NbPMe₃ (silox = ^tBu₃SiO) under Dihydrogen Leads to (silox)₃NbCH₂, (silox)₃NbPH or (silox)₃NbP(H)Nb(silox)₃, and CH₄

A Transient V^III–Alkylidene Complex: Oxidation Chemistry Including the Activation of N₂ to Afford a Highly Porous Honeycomb‐Like Framework

Four-Coordinate Mo(II) as (silox)₂Mo(PMe₃)₂and Its W(IV) Congener (silox)₂HW(η²-CH₂PMe₂)(PMe₃) (silox =^tBu₃SiO)