Intermolecular [2 + 2 + 2] Cycloaddition Reactions of Alkynes and Alkenes Mediated by Cobalt

X-ray Crystal Structures of Two Isomeric (η5-Cyclopentadienyl)(η4-1,3-cyclohexadiene)cobalt Complexes

David W. Macomber, Akhilkumar G. Verma, Robin D. Rogers

Research output: Contribution to journalArticle

33 Citations (Scopus)

Abstract

Treatment of bicyclic alkenes (norbornylene, endo-dicyclopentadiene) with alkynes (diphenylacetylene, dimethyl acetylenedicarboxylate) in the presence of CpCo(CO)2produced CpCo(η4-1,3-cyclohexadiene) complexes (1, 2, 6, 7, 10, 11) in good yields. Oxidation of complexes 1, 2, 6, 7, 10, and 11 using CuCl2·2H2O afforded the free diene ligands 4, 8, and 13. Further oxidation of 4 and 8 using ceric ammonium nitrate produced the aromatic derivatives 5 and 9. The isomeric complexes 1 and 2, which were obtained from endo-dicyclopentadiene and diphenylacetylene, were characterized by two-dimensional NMR spectroscopic techniques as well as X-ray crystallography. Complex 1 isomerized to 2 at 154 °C in a first-order process with an observed rate constant of (1.5 ± 0.1) × 10-5 s-1. Treatment of norbornylene with diphenylacetylene in the presence of (η5-C5H4CH3)Co(CO)2produced two isomeric (η5-C5H4CH3)Co(η4-1,3-cyclohexadiene) complexes (14, 15). A 1:1 mixture of 1 and 14 isomerized intramolecularly to 2 and 15 in xylene-d10 at 155 °C. Both 1 and 2 are triclinic, P1̅; 1 has unit cell parameters a = 10.943 (2) Å, b = 11.439 (1) Å, c = 14.954 (6) Å, α = 71.94 (3)°, β = 87.00 (3)°, γ = 62.27 (1)°, and D(calcd) = 1.30 g cm-3for Z = 2. These values for 2 are a = 10.752 (1) Å, b = 12.640 (3) Å, c = 13.754 (3) Å, α = 69.89 (3)°, β= 66.83 (1)°, γ = 68.38 (1)°, and D(calcd) = 1.31 g cm-3for Z = 2. Both were refined via least-squares, 1 to a conventional R value of 0.041 based on 4605 independent observed reflections ([Fo≥ 5σ(Fo)] and 2 to 0.041 utilizing 3530 reflections. Each cobalt atom is η5-coordinated to the cyclopentadienyl ligand (Co-Cp(av) = 2.09 (2) Å for 1 and 2.08 (3) Å for 2) and η4-bonded to the 1,3-cyclohexadiene ligand. The two exterior Co-C distances average 2.08 (3) Å in 1 and 2.07 (2) Å in 2, whereas the two interior Co-C values average 1.97 (1) and 1.984 (8) Å, respectively.

Original languageEnglish (US)
Pages (from-to)1241-1253
Number of pages13
JournalOrganometallics
Volume7
Issue number6
DOIs
StatePublished - Jan 1 1988

Fingerprint

dicyclopentadiene
Alkynes
Cycloaddition
cycloaddition
Alkenes
alkynes
Cobalt
alkenes
cobalt
Crystal structure
Ligands
X rays
ligands
crystal structure
ammonium nitrates
Oxidation
Xylenes
oxidation
x rays
X ray crystallography

Cite this

@article{00fe0ed9dcb34cf989f5313b72ad53b6,
title = "Intermolecular [2 + 2 + 2] Cycloaddition Reactions of Alkynes and Alkenes Mediated by Cobalt: X-ray Crystal Structures of Two Isomeric (η5-Cyclopentadienyl)(η4-1,3-cyclohexadiene)cobalt Complexes",
abstract = "Treatment of bicyclic alkenes (norbornylene, endo-dicyclopentadiene) with alkynes (diphenylacetylene, dimethyl acetylenedicarboxylate) in the presence of CpCo(CO)2produced CpCo(η4-1,3-cyclohexadiene) complexes (1, 2, 6, 7, 10, 11) in good yields. Oxidation of complexes 1, 2, 6, 7, 10, and 11 using CuCl2·2H2O afforded the free diene ligands 4, 8, and 13. Further oxidation of 4 and 8 using ceric ammonium nitrate produced the aromatic derivatives 5 and 9. The isomeric complexes 1 and 2, which were obtained from endo-dicyclopentadiene and diphenylacetylene, were characterized by two-dimensional NMR spectroscopic techniques as well as X-ray crystallography. Complex 1 isomerized to 2 at 154 °C in a first-order process with an observed rate constant of (1.5 ± 0.1) × 10-5 s-1. Treatment of norbornylene with diphenylacetylene in the presence of (η5-C5H4CH3)Co(CO)2produced two isomeric (η5-C5H4CH3)Co(η4-1,3-cyclohexadiene) complexes (14, 15). A 1:1 mixture of 1 and 14 isomerized intramolecularly to 2 and 15 in xylene-d10 at 155 °C. Both 1 and 2 are triclinic, P1̅; 1 has unit cell parameters a = 10.943 (2) {\AA}, b = 11.439 (1) {\AA}, c = 14.954 (6) {\AA}, α = 71.94 (3)°, β = 87.00 (3)°, γ = 62.27 (1)°, and D(calcd) = 1.30 g cm-3for Z = 2. These values for 2 are a = 10.752 (1) {\AA}, b = 12.640 (3) {\AA}, c = 13.754 (3) {\AA}, α = 69.89 (3)°, β= 66.83 (1)°, γ = 68.38 (1)°, and D(calcd) = 1.31 g cm-3for Z = 2. Both were refined via least-squares, 1 to a conventional R value of 0.041 based on 4605 independent observed reflections ([Fo≥ 5σ(Fo)] and 2 to 0.041 utilizing 3530 reflections. Each cobalt atom is η5-coordinated to the cyclopentadienyl ligand (Co-Cp(av) = 2.09 (2) {\AA} for 1 and 2.08 (3) {\AA} for 2) and η4-bonded to the 1,3-cyclohexadiene ligand. The two exterior Co-C distances average 2.08 (3) {\AA} in 1 and 2.07 (2) {\AA} in 2, whereas the two interior Co-C values average 1.97 (1) and 1.984 (8) {\AA}, respectively.",
author = "Macomber, {David W.} and Verma, {Akhilkumar G.} and Rogers, {Robin D.}",
year = "1988",
month = "1",
day = "1",
doi = "10.1021/om00096a002",
language = "English (US)",
volume = "7",
pages = "1241--1253",
journal = "Organometallics",
issn = "0276-7333",
publisher = "American Chemical Society",
number = "6",

}

TY - JOUR

T1 - Intermolecular [2 + 2 + 2] Cycloaddition Reactions of Alkynes and Alkenes Mediated by Cobalt

T2 - X-ray Crystal Structures of Two Isomeric (η5-Cyclopentadienyl)(η4-1,3-cyclohexadiene)cobalt Complexes

AU - Macomber, David W.

AU - Verma, Akhilkumar G.

AU - Rogers, Robin D.

PY - 1988/1/1

Y1 - 1988/1/1

N2 - Treatment of bicyclic alkenes (norbornylene, endo-dicyclopentadiene) with alkynes (diphenylacetylene, dimethyl acetylenedicarboxylate) in the presence of CpCo(CO)2produced CpCo(η4-1,3-cyclohexadiene) complexes (1, 2, 6, 7, 10, 11) in good yields. Oxidation of complexes 1, 2, 6, 7, 10, and 11 using CuCl2·2H2O afforded the free diene ligands 4, 8, and 13. Further oxidation of 4 and 8 using ceric ammonium nitrate produced the aromatic derivatives 5 and 9. The isomeric complexes 1 and 2, which were obtained from endo-dicyclopentadiene and diphenylacetylene, were characterized by two-dimensional NMR spectroscopic techniques as well as X-ray crystallography. Complex 1 isomerized to 2 at 154 °C in a first-order process with an observed rate constant of (1.5 ± 0.1) × 10-5 s-1. Treatment of norbornylene with diphenylacetylene in the presence of (η5-C5H4CH3)Co(CO)2produced two isomeric (η5-C5H4CH3)Co(η4-1,3-cyclohexadiene) complexes (14, 15). A 1:1 mixture of 1 and 14 isomerized intramolecularly to 2 and 15 in xylene-d10 at 155 °C. Both 1 and 2 are triclinic, P1̅; 1 has unit cell parameters a = 10.943 (2) Å, b = 11.439 (1) Å, c = 14.954 (6) Å, α = 71.94 (3)°, β = 87.00 (3)°, γ = 62.27 (1)°, and D(calcd) = 1.30 g cm-3for Z = 2. These values for 2 are a = 10.752 (1) Å, b = 12.640 (3) Å, c = 13.754 (3) Å, α = 69.89 (3)°, β= 66.83 (1)°, γ = 68.38 (1)°, and D(calcd) = 1.31 g cm-3for Z = 2. Both were refined via least-squares, 1 to a conventional R value of 0.041 based on 4605 independent observed reflections ([Fo≥ 5σ(Fo)] and 2 to 0.041 utilizing 3530 reflections. Each cobalt atom is η5-coordinated to the cyclopentadienyl ligand (Co-Cp(av) = 2.09 (2) Å for 1 and 2.08 (3) Å for 2) and η4-bonded to the 1,3-cyclohexadiene ligand. The two exterior Co-C distances average 2.08 (3) Å in 1 and 2.07 (2) Å in 2, whereas the two interior Co-C values average 1.97 (1) and 1.984 (8) Å, respectively.

AB - Treatment of bicyclic alkenes (norbornylene, endo-dicyclopentadiene) with alkynes (diphenylacetylene, dimethyl acetylenedicarboxylate) in the presence of CpCo(CO)2produced CpCo(η4-1,3-cyclohexadiene) complexes (1, 2, 6, 7, 10, 11) in good yields. Oxidation of complexes 1, 2, 6, 7, 10, and 11 using CuCl2·2H2O afforded the free diene ligands 4, 8, and 13. Further oxidation of 4 and 8 using ceric ammonium nitrate produced the aromatic derivatives 5 and 9. The isomeric complexes 1 and 2, which were obtained from endo-dicyclopentadiene and diphenylacetylene, were characterized by two-dimensional NMR spectroscopic techniques as well as X-ray crystallography. Complex 1 isomerized to 2 at 154 °C in a first-order process with an observed rate constant of (1.5 ± 0.1) × 10-5 s-1. Treatment of norbornylene with diphenylacetylene in the presence of (η5-C5H4CH3)Co(CO)2produced two isomeric (η5-C5H4CH3)Co(η4-1,3-cyclohexadiene) complexes (14, 15). A 1:1 mixture of 1 and 14 isomerized intramolecularly to 2 and 15 in xylene-d10 at 155 °C. Both 1 and 2 are triclinic, P1̅; 1 has unit cell parameters a = 10.943 (2) Å, b = 11.439 (1) Å, c = 14.954 (6) Å, α = 71.94 (3)°, β = 87.00 (3)°, γ = 62.27 (1)°, and D(calcd) = 1.30 g cm-3for Z = 2. These values for 2 are a = 10.752 (1) Å, b = 12.640 (3) Å, c = 13.754 (3) Å, α = 69.89 (3)°, β= 66.83 (1)°, γ = 68.38 (1)°, and D(calcd) = 1.31 g cm-3for Z = 2. Both were refined via least-squares, 1 to a conventional R value of 0.041 based on 4605 independent observed reflections ([Fo≥ 5σ(Fo)] and 2 to 0.041 utilizing 3530 reflections. Each cobalt atom is η5-coordinated to the cyclopentadienyl ligand (Co-Cp(av) = 2.09 (2) Å for 1 and 2.08 (3) Å for 2) and η4-bonded to the 1,3-cyclohexadiene ligand. The two exterior Co-C distances average 2.08 (3) Å in 1 and 2.07 (2) Å in 2, whereas the two interior Co-C values average 1.97 (1) and 1.984 (8) Å, respectively.

UR - http://www.scopus.com/inward/record.url?scp=0038662179&partnerID=8YFLogxK

UR - http://www.scopus.com/inward/citedby.url?scp=0038662179&partnerID=8YFLogxK

U2 - 10.1021/om00096a002

DO - 10.1021/om00096a002

M3 - Article

VL - 7

SP - 1241

EP - 1253

JO - Organometallics

JF - Organometallics

SN - 0276-7333

IS - 6

ER -