Isolation and structural characterization of unsolvated lithium aryls

Karin Ruhlandt, Jeffrey J. Ellison, Rudolf J. Wehmschulte, Frank Pauer, Philip P. Power

Research output: Contribution to journalArticle

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Abstract

The synthesis and characterization of three examples of unsolvated lithium aryls are described. The compounds {Li(Trip)}4 (1, Trip = 2,4,6-i-Pr3C6H2), {Li(2,6-Mes2C6H3)}2 (2, Mes = 2,4,6-Me3C6H2), {Li(n-Bu)}2(LiMes*)2 (3), and {Li(n-Bu)}2(LiMes*)2·Mes*Br (3·Mes*Br, Mes* = 2,4,6-t-Bu3C6H2) were synthesized by a metal-halogen exchange reaction between n-butyllithium and the appropriate aryl bromide (1 and 3) or iodide (2). The X-ray crystal structures of 1 and 3 show that they are tetrametallic lithium species involving almost planar arrays of four lithium atoms. The bonding involves both σ- and π-interactions to the aryl ligands. In contrast, the structure of 2 is dimeric with the two aryl groups linked by two μ2-bridging lithiums which are primarily σ-bonded to ipso carbons. Weaker interactions were also observed between the ortho mesityl substituents and the lithiums. The structure of 3·Mes*Br shows that the halide starting material Mes*Br can be included in the isolated crystals. This is a consequence of the fact that the metal-halogen exchange reaction used in their synthesis is sluggish. The main reasons for this probably are the use of hydrocarbon rather than ether solvent and the large size of the aryl ligands. The compounds were characterized by 1H, 13C, and 7Li NMR spectroscopy and X-ray crystallography and represent the first examples of structurally characterized simple, nonsolvated, σ-bonded lithium aryls. Crystal data with Mo Kα (λ = 0.71069 Å) at 130 K: 1, a = b = 13.098(2) Å, c = 16.791(8) Å, V = 2881(2) Å3, Z = 2, space group I4̄, 597 (I > 2σ(I)) data, R = 0.089; 2, a = 30.190(7) Å, b = 13.423(2) Å, c = 19.048(4) Å, V = 7719(3) Å3, Z = 8 (two independent molecules), space group Pnna, 3419 (I > 2σ(I)) data, R = 0.097; 3, a = 22.721 (11) Å, b = 10.072(5) Å, c = 19.327(8) Å, V = 4423(3) Å3, Z = 4, space group Pna21, 1811 (I > 2.5σ(I)) data, R = 0.082; 3·Mes*Br, a = 11.385(2) Å, b = 15.261(3) Å, c = 17.458(5) Å, β = 91.16(2)°, V = 3032.4(12) Å3, Z = 2, space group C2/m, 1821 (I > 3σ(I)) data, R = 0.104.

Original languageEnglish (US)
Pages (from-to)11353-11357
Number of pages5
JournalJournal of the American Chemical Society
Volume115
Issue number24
StatePublished - 1993
Externally publishedYes

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Lithium
Halogens
Metals
Ligands
Crystals
X ray crystallography
X Ray Crystallography
Iodides
Hydrocarbons
Bromides
Ether
Nuclear magnetic resonance spectroscopy
Ethers
Ion exchange
Magnetic Resonance Spectroscopy
Carbon
Crystal structure
X-Rays
X rays
Atoms

ASJC Scopus subject areas

  • Chemistry(all)

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Ruhlandt, K., Ellison, J. J., Wehmschulte, R. J., Pauer, F., & Power, P. P. (1993). Isolation and structural characterization of unsolvated lithium aryls. Journal of the American Chemical Society, 115(24), 11353-11357.

Isolation and structural characterization of unsolvated lithium aryls. / Ruhlandt, Karin; Ellison, Jeffrey J.; Wehmschulte, Rudolf J.; Pauer, Frank; Power, Philip P.

In: Journal of the American Chemical Society, Vol. 115, No. 24, 1993, p. 11353-11357.

Research output: Contribution to journalArticle

Ruhlandt, K, Ellison, JJ, Wehmschulte, RJ, Pauer, F & Power, PP 1993, 'Isolation and structural characterization of unsolvated lithium aryls', Journal of the American Chemical Society, vol. 115, no. 24, pp. 11353-11357.
Ruhlandt, Karin ; Ellison, Jeffrey J. ; Wehmschulte, Rudolf J. ; Pauer, Frank ; Power, Philip P. / Isolation and structural characterization of unsolvated lithium aryls. In: Journal of the American Chemical Society. 1993 ; Vol. 115, No. 24. pp. 11353-11357.
@article{0017122917f34210a77dda2a807a6f70,
title = "Isolation and structural characterization of unsolvated lithium aryls",
abstract = "The synthesis and characterization of three examples of unsolvated lithium aryls are described. The compounds {Li(Trip)}4 (1, Trip = 2,4,6-i-Pr3C6H2), {Li(2,6-Mes2C6H3)}2 (2, Mes = 2,4,6-Me3C6H2), {Li(n-Bu)}2(LiMes*)2 (3), and {Li(n-Bu)}2(LiMes*)2·Mes*Br (3·Mes*Br, Mes* = 2,4,6-t-Bu3C6H2) were synthesized by a metal-halogen exchange reaction between n-butyllithium and the appropriate aryl bromide (1 and 3) or iodide (2). The X-ray crystal structures of 1 and 3 show that they are tetrametallic lithium species involving almost planar arrays of four lithium atoms. The bonding involves both σ- and π-interactions to the aryl ligands. In contrast, the structure of 2 is dimeric with the two aryl groups linked by two μ2-bridging lithiums which are primarily σ-bonded to ipso carbons. Weaker interactions were also observed between the ortho mesityl substituents and the lithiums. The structure of 3·Mes*Br shows that the halide starting material Mes*Br can be included in the isolated crystals. This is a consequence of the fact that the metal-halogen exchange reaction used in their synthesis is sluggish. The main reasons for this probably are the use of hydrocarbon rather than ether solvent and the large size of the aryl ligands. The compounds were characterized by 1H, 13C, and 7Li NMR spectroscopy and X-ray crystallography and represent the first examples of structurally characterized simple, nonsolvated, σ-bonded lithium aryls. Crystal data with Mo Kα (λ = 0.71069 {\AA}) at 130 K: 1, a = b = 13.098(2) {\AA}, c = 16.791(8) {\AA}, V = 2881(2) {\AA}3, Z = 2, space group I4̄, 597 (I > 2σ(I)) data, R = 0.089; 2, a = 30.190(7) {\AA}, b = 13.423(2) {\AA}, c = 19.048(4) {\AA}, V = 7719(3) {\AA}3, Z = 8 (two independent molecules), space group Pnna, 3419 (I > 2σ(I)) data, R = 0.097; 3, a = 22.721 (11) {\AA}, b = 10.072(5) {\AA}, c = 19.327(8) {\AA}, V = 4423(3) {\AA}3, Z = 4, space group Pna21, 1811 (I > 2.5σ(I)) data, R = 0.082; 3·Mes*Br, a = 11.385(2) {\AA}, b = 15.261(3) {\AA}, c = 17.458(5) {\AA}, β = 91.16(2)°, V = 3032.4(12) {\AA}3, Z = 2, space group C2/m, 1821 (I > 3σ(I)) data, R = 0.104.",
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TY - JOUR

T1 - Isolation and structural characterization of unsolvated lithium aryls

AU - Ruhlandt, Karin

AU - Ellison, Jeffrey J.

AU - Wehmschulte, Rudolf J.

AU - Pauer, Frank

AU - Power, Philip P.

PY - 1993

Y1 - 1993

N2 - The synthesis and characterization of three examples of unsolvated lithium aryls are described. The compounds {Li(Trip)}4 (1, Trip = 2,4,6-i-Pr3C6H2), {Li(2,6-Mes2C6H3)}2 (2, Mes = 2,4,6-Me3C6H2), {Li(n-Bu)}2(LiMes*)2 (3), and {Li(n-Bu)}2(LiMes*)2·Mes*Br (3·Mes*Br, Mes* = 2,4,6-t-Bu3C6H2) were synthesized by a metal-halogen exchange reaction between n-butyllithium and the appropriate aryl bromide (1 and 3) or iodide (2). The X-ray crystal structures of 1 and 3 show that they are tetrametallic lithium species involving almost planar arrays of four lithium atoms. The bonding involves both σ- and π-interactions to the aryl ligands. In contrast, the structure of 2 is dimeric with the two aryl groups linked by two μ2-bridging lithiums which are primarily σ-bonded to ipso carbons. Weaker interactions were also observed between the ortho mesityl substituents and the lithiums. The structure of 3·Mes*Br shows that the halide starting material Mes*Br can be included in the isolated crystals. This is a consequence of the fact that the metal-halogen exchange reaction used in their synthesis is sluggish. The main reasons for this probably are the use of hydrocarbon rather than ether solvent and the large size of the aryl ligands. The compounds were characterized by 1H, 13C, and 7Li NMR spectroscopy and X-ray crystallography and represent the first examples of structurally characterized simple, nonsolvated, σ-bonded lithium aryls. Crystal data with Mo Kα (λ = 0.71069 Å) at 130 K: 1, a = b = 13.098(2) Å, c = 16.791(8) Å, V = 2881(2) Å3, Z = 2, space group I4̄, 597 (I > 2σ(I)) data, R = 0.089; 2, a = 30.190(7) Å, b = 13.423(2) Å, c = 19.048(4) Å, V = 7719(3) Å3, Z = 8 (two independent molecules), space group Pnna, 3419 (I > 2σ(I)) data, R = 0.097; 3, a = 22.721 (11) Å, b = 10.072(5) Å, c = 19.327(8) Å, V = 4423(3) Å3, Z = 4, space group Pna21, 1811 (I > 2.5σ(I)) data, R = 0.082; 3·Mes*Br, a = 11.385(2) Å, b = 15.261(3) Å, c = 17.458(5) Å, β = 91.16(2)°, V = 3032.4(12) Å3, Z = 2, space group C2/m, 1821 (I > 3σ(I)) data, R = 0.104.

AB - The synthesis and characterization of three examples of unsolvated lithium aryls are described. The compounds {Li(Trip)}4 (1, Trip = 2,4,6-i-Pr3C6H2), {Li(2,6-Mes2C6H3)}2 (2, Mes = 2,4,6-Me3C6H2), {Li(n-Bu)}2(LiMes*)2 (3), and {Li(n-Bu)}2(LiMes*)2·Mes*Br (3·Mes*Br, Mes* = 2,4,6-t-Bu3C6H2) were synthesized by a metal-halogen exchange reaction between n-butyllithium and the appropriate aryl bromide (1 and 3) or iodide (2). The X-ray crystal structures of 1 and 3 show that they are tetrametallic lithium species involving almost planar arrays of four lithium atoms. The bonding involves both σ- and π-interactions to the aryl ligands. In contrast, the structure of 2 is dimeric with the two aryl groups linked by two μ2-bridging lithiums which are primarily σ-bonded to ipso carbons. Weaker interactions were also observed between the ortho mesityl substituents and the lithiums. The structure of 3·Mes*Br shows that the halide starting material Mes*Br can be included in the isolated crystals. This is a consequence of the fact that the metal-halogen exchange reaction used in their synthesis is sluggish. The main reasons for this probably are the use of hydrocarbon rather than ether solvent and the large size of the aryl ligands. The compounds were characterized by 1H, 13C, and 7Li NMR spectroscopy and X-ray crystallography and represent the first examples of structurally characterized simple, nonsolvated, σ-bonded lithium aryls. Crystal data with Mo Kα (λ = 0.71069 Å) at 130 K: 1, a = b = 13.098(2) Å, c = 16.791(8) Å, V = 2881(2) Å3, Z = 2, space group I4̄, 597 (I > 2σ(I)) data, R = 0.089; 2, a = 30.190(7) Å, b = 13.423(2) Å, c = 19.048(4) Å, V = 7719(3) Å3, Z = 8 (two independent molecules), space group Pnna, 3419 (I > 2σ(I)) data, R = 0.097; 3, a = 22.721 (11) Å, b = 10.072(5) Å, c = 19.327(8) Å, V = 4423(3) Å3, Z = 4, space group Pna21, 1811 (I > 2.5σ(I)) data, R = 0.082; 3·Mes*Br, a = 11.385(2) Å, b = 15.261(3) Å, c = 17.458(5) Å, β = 91.16(2)°, V = 3032.4(12) Å3, Z = 2, space group C2/m, 1821 (I > 3σ(I)) data, R = 0.104.

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