Synthesis of alkylidyne tungsten complexes with hydrotris(pyrazol-1-yl)borate ligands

Jeffery, John C.; Gordon, F.; Stone, A.; Williams, Geoffrey K.

doi:10.1016/s0277-5387(00)81591-0

Cited by 20 publications

(9 citation statements)

References 21 publications

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“…A dative bond from a heteroatom substituent is an alternate source of electron density. The thiomethoxy carbene complex [Tp(CO) 2 WC(SMe)H][OTf] possesses a sulfur−metal dative bond, and the o -anisyl carbene complex [Tp(CO) 2 WC(2-C 6 H 4 OMe)H][BF 4 ] is thought to be stabilized by an oxygen−metal dative bond . In our system, an agostic bond is favored over an oxygen−metal dative bond for stabilizing the unsaturated metal center.…”

Section: Resultsmentioning

confidence: 95%

Sequential Chemical Transformations of a Tungsten Carbyne Ligand: Protonation, Alkyne Insertion, Vinylcarbene Formation, and Metallacyclopropene/Metallafuran Isomerization

et al. 2003

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Proton addition and phenylacetylene insertion convert carbyne complexes of the type Tp′(CO) 2 WtC-OAr (Ar ) Ph, p-C 6 H 4 Me, p-C 6 H 4 OMe; Tp′ ) hydridotris(3,5-dimethylpyrazolyl)borate) into tungsten η 3 -vinylcarbene complexes of the form [Tp′(CO) was characterized by IR, 1 H NMR, and 13 C NMR spectroscopy. Addition of base to the cationic vinylcarbene complex 6 forms the metallafuran complex 9) as the major product. Although the net reaction corresponds to loss of C 6 H 5 + , mechanistically it is attractive to postulate addition of OHto the electron-deficient C γ site followed by proton removal by base coupled with loss of OPhto generate the metallafuran stoichiometry. Isolation of an intermediate metallacyclopropene complex (10), possessing an aldehyde substituent on the three-membered ring, which isomerizes to the thermodynamically favored metallafuran complex, is consistent with this mechanism. The vinylcarbyne complex Tp′(CO) 2 WtC-CPhdCH(OTol) (11b) was also recovered from the reaction mixture of complex 6b and base. Addition of 0.10 equiv of H[BF 4 ] to metallacyclopropene complex 10 resulted in complete conversion of 10 to the metallafuran complex 9 at room temperature. Addition of acid to metallacyclopropene complex 10 at low temperature allowed 1 H NMR characterization of the η 3 -vinylcarbene intermediate [Tp′-(CO) 2 W(η 3 -(C R ,C β ,C γ )dCPh-CHdCH(OH))][BF 4 ] (17). Upon addition of Li[Et 3 BH] to 6, double hydride addition and loss of aryloxide occurred at C γ of the aryloxy-substituted vinylcarbene complex 6 to form the previously reported η 2 -vinyl complex Tp′(CO) 2 W(η 2 -(C R ,C β )CPhdCH-CH 3 ) (8). These experiments illustrate reaction routes available to C 3 ligand skeletons derived from carbyne-alkyne coupling. The oxygen of the aryloxy substituent on the original carbyne carbon plays an integral role in this reaction sequence.

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Section: Resultsmentioning

confidence: 95%

Sequential Chemical Transformations of a Tungsten Carbyne Ligand: Protonation, Alkyne Insertion, Vinylcarbene Formation, and Metallacyclopropene/Metallafuran Isomerization

et al. 2003

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“… The complexes 2a−c can also be prepared from KTp Ph and anhydrous cobalt salts in dichloromethane. Trofimenko et al have determined the crystal structure of a redtetrahydrofuran adduct of [(Tp Ph )CoNCS] ( 2c ) 7a…”

Section: Resultsmentioning

confidence: 99%

“…Membrane filters (regenerated cellulose, 1.0 μm, Schleicher & Schuell) were used to filter off small particles. KTp Ph , the halogeno complexes [(Tp Ph )ZnX] (X = Cl, Br, I, SCN), and [(Tp Ph )Co(SCN)THF] were obtained according to literature procedures . Sodium acetylacetonate was prepared by adding sodium methylate to acetylacetone in methanol/THF (1:1).…”

Section: Methodsmentioning

confidence: 99%

Cobalt as a Probe for Zinc in Metalloenzyme Model Compounds? A Comparison of Spectroscopic Features and Coordination Geometry of Four- and Five-Coordinate Complexes. Crystal and Molecular Structures of [Co(η³-Tp^Ph)(η²-Tp^Ph)], [(η³-Tp^Ph)Zn(anthranilate)], and [(η³-Tp^Ph)M(η²-acac)] (Tp^Ph= Hydrotris(3-phenylpyrazol-1-yl)borate, acac = Pentane-2,4-dionate, and M = Zn, Co)

et al. 1997

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The reaction of cobalt(II) perchlorate with 1 equiv each of potassium hydroxide and potassium hydrotris(3-phenylpyrazolyl)borate (KTp(Ph)) leads to the formation of the blood-red bis(ligand) complex [Co(eta(3)-Tp(Ph))(eta(2)-Tp(Ph))]. This compound crystallizes in the monoclinic space group P2(1)/n, with a = 10.690(5) Å, b = 34.243(15) Å, c = 12.923(4) Å, beta = 96.17(3) degrees, Z = 4, V = 4703(3) Å(3), and R = 0.040. The molecular structure contains a square CoN(5) pyramid with an agostic BH.Co interaction of 2.17(2) Å. One Tp(Ph) ligand acts tridentate; the other, bidentate. The reaction of KTp(Ph) with zinc and cobalt halides yields a series of heteroleptic halogeno complexes [(Tp(Ph))MX]. The zinc species are all tetrahedral, while in the case of cobalt(II) the UV-vis spectra indicate an equilibrium of tetra- and pentacoordinated species depending on the anion size and the donor properties of the solvent. Metathesis reactions with carboxylates yield mononuclear complexes [(Tp(Ph))M(O(2)CR)]; M = Zn(II), Co(II); RCO(2)(-) = acetate, benzoate, 4-fluorobenzoate, and 4-nitrobenzoate. The infrared bands nu(as)(CO(2)) and nu(sym)(CO(2)) indicate monodentate carboxylate ligands in the zinc complexes in the solid state and in solution. The cobalt complexes [(Tp(Ph))Co(carboxylate)] are dark blue in dichloromethane and in the solid state when grown from dichloromethane solution. Tetrahydrofuran solutions and crystals grown from tetrahydrofuran are pink, purple, or reddish violet. The 2-aminobenzoate (anthranilate) complexes [(Th(Ph))M(anthranilate)], M = Zn(II), Co(II), have been prepared. [(eta(3)-Tp(Ph))Zn(anthranilate)] crystallizes in the monoclinic space group P2(1)/n, with a = 13.205(4) Å, b = 15.643(3) Å, c = 15.116(3) Å, beta = 98.86(2) degrees, Z = 4, V = 3085(1) Å(3), and R = 0.034. Anthranilate acts as a chelating oxygen ligand with Zn-O distances of 1.932(2) and 2.460(2) Å. The amino group is not involved in metal coordination. The reaction of the chloro complexes [(Tp(Ph))MCl] with sodium or potassium acetylacetonate leads to isotypic zinc and cobalt complexes [(eta(3)-Tp(Ph))M(eta(2)-acac)]. Both crystallize in the monoclinic space group P2(1)/c, with Z = 4, the zinc compound with a = 16.334(3) Å, b = 11.545(2) Å, c = 15.816(3) Å, beta = 94.77(1) degrees, V = 2972(1) Å(3), and R = 0.039 and the cobalt compound with a = 16.358(7) Å, b = 11.519(2) Å, c = 15.847(6) Å, beta = 95.30(3) degrees, V = 2973(2) Å(3), and R = 0.035. The structures are best described as slightly distorted trigonal bipyramids with the two axial positions occupied by one of the acetylacetonate O and one of the tripodal N donor atoms. Ligand profiles of Tp(Ph) and related ligands have been calculated to visualize the angular encumbrance of the ligands.

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“…Notably, the same shift (ca. 50 cm −1 ) to higher values is observed for the ν(CO) absorption bands of [Tp′(CO) 2 WC(PMe 2 Ph)][PF 6 ] (2022 and 1934 cm −1 in acetonitrile) versus those of [Tp′(CO) 2 WC(C 6 H 4 -4-Me)] (1974 and 1888 cm −1 in n-hexane) 26 as that found for the Ge compounds described above.…”

Section: ■ Introductionmentioning

confidence: 94%

Coordination Chemistry of [E(Idipp)]²⁺Ligands (E = Ge, Sn): Metal Germylidyne [Cp(CO)₂W≡Ge(Idipp)]⁺and Metallotetrylene [Cp(CO)₃W–E(Idipp)]⁺Cations

et al. 2017

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The synthesis and full characterization of the NHC-stabilized tungstenochlorostannylene [Cp*(CO)3W–SnCl(Idipp)] (1Sn), the NHC-stabilized chlorogermylidyne complex [Cp*(CO)2WGeCl(Idipp)] (2), the tungsten germylidyne complex salt [Cp*(CO)2WGe(Idipp)][B(C6H3-3,5-(CF3)2)4] (3), and the cationic metallostannylene [Cp*(CO)3W–Sn(Idipp)][Al(OC(CF3)3)4] (4Sn) are reported (Idipp = 2,3-dihydro-1,3-bis(2,6-diisopropylphenyl)-1H-imidazol-2-ylidene, Cp* = η 5-C5Me5). Metathetical exchange of SnCl2(Idipp) with Li[Cp*W(CO)3] afforded selectively 1Sn. Photolytic decarbonylation of the Ge analogue [Cp*(CO)3W–GeCl(Idipp)] (1Ge) afforded the NHC-stabilized chlorogermylidyne complex (2), featuring a trigonal-planar coordinated germanium center and a W–Ge double bond (W–Ge 2.3496(5) Å). Chloride abstraction from 2 with Na[B(C6H3-3,5-(CF3)2)4] yielded the germylidyne complex salt 3, which contains an almost linear W–Ge–C1 linkage (angle at Ge = 168.7(1)°) and a W–Ge triple bond (2.2813(4) Å). Chloride elimination from 1Ge afforded the tungstenogermylene salt [Cp*(CO)3W–Ge(Idipp)][B(C6H3-3,5-(CF3)2)4] (4Ge), which in contrast to 1Ge could not be decarbonylated to form 3 despite the less strongly bound carbonyl ligands. The tin compounds 1Sn and 4Sn did not afford products bearing multiple W–Sn bonds. Treatment of 4Ge with Me2NCCNMe2 yielded unexpectedly the neutral germyl complex 5 containing a pendant 1-germabicyclo-[3,2,0]-hepta-2,5-diene ligand instead of the anticipated [2 + 1]-cycloaddition product at the Ge-center.

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Synthesis of alkylidyne tungsten complexes with hydrotris(pyrazol-1-yl)borate ligands

Cited by 20 publications

References 21 publications

Sequential Chemical Transformations of a Tungsten Carbyne Ligand: Protonation, Alkyne Insertion, Vinylcarbene Formation, and Metallacyclopropene/Metallafuran Isomerization

Sequential Chemical Transformations of a Tungsten Carbyne Ligand: Protonation, Alkyne Insertion, Vinylcarbene Formation, and Metallacyclopropene/Metallafuran Isomerization

Coordination Chemistry of [E(Idipp)]²⁺Ligands (E = Ge, Sn): Metal Germylidyne [Cp(CO)₂W≡Ge(Idipp)]⁺and Metallotetrylene [Cp(CO)₃W–E(Idipp)]⁺Cations

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Synthesis of alkylidyne tungsten complexes with hydrotris(pyrazol-1-yl)borate ligands

Cited by 20 publications

References 21 publications

Sequential Chemical Transformations of a Tungsten Carbyne Ligand: Protonation, Alkyne Insertion, Vinylcarbene Formation, and Metallacyclopropene/Metallafuran Isomerization

Sequential Chemical Transformations of a Tungsten Carbyne Ligand: Protonation, Alkyne Insertion, Vinylcarbene Formation, and Metallacyclopropene/Metallafuran Isomerization

Coordination Chemistry of [E(Idipp)]2+Ligands (E = Ge, Sn): Metal Germylidyne [Cp*(CO)2W≡Ge(Idipp)]+and Metallotetrylene [Cp*(CO)3W–E(Idipp)]+Cations

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Coordination Chemistry of [E(Idipp)]²⁺Ligands (E = Ge, Sn): Metal Germylidyne [Cp(CO)₂W≡Ge(Idipp)]⁺and Metallotetrylene [Cp(CO)₃W–E(Idipp)]⁺Cations