Dinuclear coordination of a novel four-electron reduced μ-η13-allene ligand with β-agostic C-H⋯Ta interaction

Direct addition of allene to (C5Me 5)2Ta2

Jui-Hsien Huang, Ting Yu Lee, Dale C. Swenson, Louis Messerle

Research output: Contribution to journalArticle

3 Citations (Scopus)

Abstract

The organoditantalum complexes (η-C5Me5) 2Ta2(μ-X)4 (X = Cl, Br) react with 1-5 equiv. of allene under mild conditions to afford the fluxional allene adducts (C5Me5)2Ta2(μ-η1, η3-C3H4)(μ-X)X3 as shown by spectroscopic and spectrometric data. Low-temperature-limit proton NMR data at -95°C for (C5Me5)2Ta2(μ- η13-C3H4)(μ-Cl)Cl 3 show a large chemical shift range for the inequivalent allene hydrogens, with a high-field value for one hydrogen at δ -0.36, and inequivalent Cp* groups. The low-temperature-limit 13C NMR resonances for the allene ligand are found at δ 204.4 (central C), δ 70.3 (CH2, 1JCH = 154 Hz), and the substantially upfield value of δ 42.9. The latter resonance has remarkably different coupling constants (1JCH = 173, 154 Hz). The allene coordinates in a novel alkylidene-diyl fashion in the solid-state, as shown by X-ray diffractometry on (C5Me5) 2Ta2(μ-η13-C 3H4)(μ-Cl)Cl3 at 200 K. One tantalum is doubly-bonded to the central allenic carbon (Ta1C22 distance, 2.011(7) Å) and interacts with an allene hydrogen in a probable β-agostic manner (Ta1-H21A distance of 2.25(10) Å). The second tantalum is coordinated to the allene in a hybrid of η3-allylic and sigma bonding, with Ta2-C distances to the allene methylenes of 2.206(8) and 2.276(9) Å and a Ta2-C22 bond distance to the central allenic carbon of 2.253(7) Å. The allene hydrogens are oriented above and below the C-C-C plane, consistent with appreciable σ-bonding between the Ta(2) and the allene methylenes. The bent allene ligand has a C-C-C angle of 106.0(6)°and can be viewed as reduced by four electrons, with concomitant oxidation of the two d2 tantalum centers of the organoditantalum(III) reactant. The long Ta⋯Ta nonbonded distance of 3.3052(8) Å is consistent with two d0 tantalum centers in an organoditantalum(V) product.

Original languageEnglish
Pages (from-to)559-567
Number of pages9
JournalPolyhedron
Volume25
Issue number2
DOIs
Publication statusPublished - 2006 Jan 23

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Tantalum
tantalum
Ligands
Hydrogen
ligands
Electrons
hydrogen
electrons
Nuclear magnetic resonance
interactions
Carbon
alkylidene
Chemical shift
nuclear magnetic resonance
X ray diffraction analysis
carbon
Protons
adducts
chemical equilibrium
Oxidation

All Science Journal Classification (ASJC) codes

  • Physical and Theoretical Chemistry
  • Inorganic Chemistry
  • Materials Chemistry

Cite this

@article{0451c49ed1034575bd072ec993a10a1c,
title = "Dinuclear coordination of a novel four-electron reduced μ-η1,η3-allene ligand with β-agostic C-H⋯Ta interaction: Direct addition of allene to (C5Me 5)2Ta2",
abstract = "The organoditantalum complexes (η-C5Me5) 2Ta2(μ-X)4 (X = Cl, Br) react with 1-5 equiv. of allene under mild conditions to afford the fluxional allene adducts (C5Me5)2Ta2(μ-η1, η3-C3H4)(μ-X)X3 as shown by spectroscopic and spectrometric data. Low-temperature-limit proton NMR data at -95°C for (C5Me5)2Ta2(μ- η1,η3-C3H4)(μ-Cl)Cl 3 show a large chemical shift range for the inequivalent allene hydrogens, with a high-field value for one hydrogen at δ -0.36, and inequivalent Cp* groups. The low-temperature-limit 13C NMR resonances for the allene ligand are found at δ 204.4 (central C), δ 70.3 (CH2, 1JCH = 154 Hz), and the substantially upfield value of δ 42.9. The latter resonance has remarkably different coupling constants (1JCH = 173, 154 Hz). The allene coordinates in a novel alkylidene-diyl fashion in the solid-state, as shown by X-ray diffractometry on (C5Me5) 2Ta2(μ-η1,η3-C 3H4)(μ-Cl)Cl3 at 200 K. One tantalum is doubly-bonded to the central allenic carbon (Ta1C22 distance, 2.011(7) {\AA}) and interacts with an allene hydrogen in a probable β-agostic manner (Ta1-H21A distance of 2.25(10) {\AA}). The second tantalum is coordinated to the allene in a hybrid of η3-allylic and sigma bonding, with Ta2-C distances to the allene methylenes of 2.206(8) and 2.276(9) {\AA} and a Ta2-C22 bond distance to the central allenic carbon of 2.253(7) {\AA}. The allene hydrogens are oriented above and below the C-C-C plane, consistent with appreciable σ-bonding between the Ta(2) and the allene methylenes. The bent allene ligand has a C-C-C angle of 106.0(6)°and can be viewed as reduced by four electrons, with concomitant oxidation of the two d2 tantalum centers of the organoditantalum(III) reactant. The long Ta⋯Ta nonbonded distance of 3.3052(8) {\AA} is consistent with two d0 tantalum centers in an organoditantalum(V) product.",
author = "Jui-Hsien Huang and Lee, {Ting Yu} and Swenson, {Dale C.} and Louis Messerle",
year = "2006",
month = "1",
day = "23",
doi = "10.1016/j.poly.2005.08.008",
language = "English",
volume = "25",
pages = "559--567",
journal = "Polyhedron",
issn = "0277-5387",
publisher = "Elsevier Limited",
number = "2",

}

Dinuclear coordination of a novel four-electron reduced μ-η13-allene ligand with β-agostic C-H⋯Ta interaction : Direct addition of allene to (C5Me 5)2Ta2. / Huang, Jui-Hsien; Lee, Ting Yu; Swenson, Dale C.; Messerle, Louis.

In: Polyhedron, Vol. 25, No. 2, 23.01.2006, p. 559-567.

Research output: Contribution to journalArticle

TY - JOUR

T1 - Dinuclear coordination of a novel four-electron reduced μ-η1,η3-allene ligand with β-agostic C-H⋯Ta interaction

T2 - Direct addition of allene to (C5Me 5)2Ta2

AU - Huang, Jui-Hsien

AU - Lee, Ting Yu

AU - Swenson, Dale C.

AU - Messerle, Louis

PY - 2006/1/23

Y1 - 2006/1/23

N2 - The organoditantalum complexes (η-C5Me5) 2Ta2(μ-X)4 (X = Cl, Br) react with 1-5 equiv. of allene under mild conditions to afford the fluxional allene adducts (C5Me5)2Ta2(μ-η1, η3-C3H4)(μ-X)X3 as shown by spectroscopic and spectrometric data. Low-temperature-limit proton NMR data at -95°C for (C5Me5)2Ta2(μ- η1,η3-C3H4)(μ-Cl)Cl 3 show a large chemical shift range for the inequivalent allene hydrogens, with a high-field value for one hydrogen at δ -0.36, and inequivalent Cp* groups. The low-temperature-limit 13C NMR resonances for the allene ligand are found at δ 204.4 (central C), δ 70.3 (CH2, 1JCH = 154 Hz), and the substantially upfield value of δ 42.9. The latter resonance has remarkably different coupling constants (1JCH = 173, 154 Hz). The allene coordinates in a novel alkylidene-diyl fashion in the solid-state, as shown by X-ray diffractometry on (C5Me5) 2Ta2(μ-η1,η3-C 3H4)(μ-Cl)Cl3 at 200 K. One tantalum is doubly-bonded to the central allenic carbon (Ta1C22 distance, 2.011(7) Å) and interacts with an allene hydrogen in a probable β-agostic manner (Ta1-H21A distance of 2.25(10) Å). The second tantalum is coordinated to the allene in a hybrid of η3-allylic and sigma bonding, with Ta2-C distances to the allene methylenes of 2.206(8) and 2.276(9) Å and a Ta2-C22 bond distance to the central allenic carbon of 2.253(7) Å. The allene hydrogens are oriented above and below the C-C-C plane, consistent with appreciable σ-bonding between the Ta(2) and the allene methylenes. The bent allene ligand has a C-C-C angle of 106.0(6)°and can be viewed as reduced by four electrons, with concomitant oxidation of the two d2 tantalum centers of the organoditantalum(III) reactant. The long Ta⋯Ta nonbonded distance of 3.3052(8) Å is consistent with two d0 tantalum centers in an organoditantalum(V) product.

AB - The organoditantalum complexes (η-C5Me5) 2Ta2(μ-X)4 (X = Cl, Br) react with 1-5 equiv. of allene under mild conditions to afford the fluxional allene adducts (C5Me5)2Ta2(μ-η1, η3-C3H4)(μ-X)X3 as shown by spectroscopic and spectrometric data. Low-temperature-limit proton NMR data at -95°C for (C5Me5)2Ta2(μ- η1,η3-C3H4)(μ-Cl)Cl 3 show a large chemical shift range for the inequivalent allene hydrogens, with a high-field value for one hydrogen at δ -0.36, and inequivalent Cp* groups. The low-temperature-limit 13C NMR resonances for the allene ligand are found at δ 204.4 (central C), δ 70.3 (CH2, 1JCH = 154 Hz), and the substantially upfield value of δ 42.9. The latter resonance has remarkably different coupling constants (1JCH = 173, 154 Hz). The allene coordinates in a novel alkylidene-diyl fashion in the solid-state, as shown by X-ray diffractometry on (C5Me5) 2Ta2(μ-η1,η3-C 3H4)(μ-Cl)Cl3 at 200 K. One tantalum is doubly-bonded to the central allenic carbon (Ta1C22 distance, 2.011(7) Å) and interacts with an allene hydrogen in a probable β-agostic manner (Ta1-H21A distance of 2.25(10) Å). The second tantalum is coordinated to the allene in a hybrid of η3-allylic and sigma bonding, with Ta2-C distances to the allene methylenes of 2.206(8) and 2.276(9) Å and a Ta2-C22 bond distance to the central allenic carbon of 2.253(7) Å. The allene hydrogens are oriented above and below the C-C-C plane, consistent with appreciable σ-bonding between the Ta(2) and the allene methylenes. The bent allene ligand has a C-C-C angle of 106.0(6)°and can be viewed as reduced by four electrons, with concomitant oxidation of the two d2 tantalum centers of the organoditantalum(III) reactant. The long Ta⋯Ta nonbonded distance of 3.3052(8) Å is consistent with two d0 tantalum centers in an organoditantalum(V) product.

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