cyclopentadienide anion


Reaction thermochemistry data

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Data compilation copyright by the U.S. Secretary of Commerce on behalf of the U.S.A. All rights reserved.

Data compiled as indicated in comments:
B - John E. Bartmess
M - Michael M. Meot-Ner (Mautner) and Sharon G. Lias

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Individual Reactions

cyclopentadienide anion + Hydrogen cation = 1,3-Cyclopentadiene

By formula: C5H5- + H+ = C5H6

Quantity Value Units Method Reference Comment
Δr353.9 ± 2.2kcal/molG+TSBartmess, Scott, et al., 1979gas phase; value altered from reference due to change in acidity scale; B
Δr354.9 ± 2.9kcal/molG+TSCumming and Kebarle, 1978gas phase; B
Δr357.2 ± 2.0kcal/molD-EAEngelking and Lineberger, 1977gas phase; B
Quantity Value Units Method Reference Comment
Δr347.7 ± 2.0kcal/molIMREBartmess, Scott, et al., 1979gas phase; value altered from reference due to change in acidity scale; B
Δr348.7 ± 2.0kcal/molIMRECumming and Kebarle, 1978gas phase; B

cyclopentadienide anion + 1,3-Cyclopentadiene = (cyclopentadienide anion • 1,3-Cyclopentadiene)

By formula: C5H5- + C5H6 = (C5H5- • C5H6)

Quantity Value Units Method Reference Comment
Δr<8.60kcal/molIMRBMeot-ner, 1988gas phase; B,M
Quantity Value Units Method Reference Comment
Δr20.cal/mol*KN/AMeot-ner, 1988gas phase; Entropy change calculated or estimated, DG<, ΔrH<; M
Quantity Value Units Method Reference Comment
Δr<2.6 ± 1.0kcal/molIMRBMeot-ner, 1988gas phase; B

Free energy of reaction

ΔrG° (kcal/mol) T (K) Method Reference Comment
3.6250.PHPMSMeot-ner, 1988gas phase; Entropy change calculated or estimated, DG<, ΔrH<; M

(cyclopentadienide anion • 2C2D3N) + C2D3N = (cyclopentadienide anion • 3C2D3N)

By formula: (C5H5- • 2C2D3N) + C2D3N = (C5H5- • 3C2D3N)

Quantity Value Units Method Reference Comment
Δr10.2kcal/molPHPMSMeot-ner, 1988gas phase; Entropy change calculated or estimated, ΔrH<, CD3CN; M
Quantity Value Units Method Reference Comment
Δr22.cal/mol*KN/AMeot-ner, 1988gas phase; Entropy change calculated or estimated, ΔrH<, CD3CN; M

Free energy of reaction

ΔrG° (kcal/mol) T (K) Method Reference Comment
5.1232.PHPMSMeot-ner, 1988gas phase; Entropy change calculated or estimated, ΔrH<, CD3CN; M

cyclopentadienide anion + Water = (cyclopentadienide anion • Water)

By formula: C5H5- + H2O = (C5H5- • H2O)

Quantity Value Units Method Reference Comment
Δr11.0 ± 1.0kcal/molTDAsMeot-ner, 1988gas phase; B,M
Quantity Value Units Method Reference Comment
Δr16.1cal/mol*KPHPMSMeot-ner, 1988gas phase; M
Quantity Value Units Method Reference Comment
Δr6.2 ± 1.0kcal/molTDAsMeot-ner, 1988gas phase; B

cyclopentadienide anion + Benzyl alcohol = (cyclopentadienide anion • Benzyl alcohol)

By formula: C5H5- + C7H8O = (C5H5- • C7H8O)

Quantity Value Units Method Reference Comment
Δr19.2 ± 1.0kcal/molTDAsMeot-ner, 1988gas phase; B,M
Quantity Value Units Method Reference Comment
Δr29.8cal/mol*KPHPMSMeot-ner, 1988gas phase; M
Quantity Value Units Method Reference Comment
Δr10.3 ± 1.0kcal/molTDAsMeot-ner, 1988gas phase; B

cyclopentadienide anion + Ethanol, 2,2,2-trifluoro- = (cyclopentadienide anion • Ethanol, 2,2,2-trifluoro-)

By formula: C5H5- + C2H3F3O = (C5H5- • C2H3F3O)

Quantity Value Units Method Reference Comment
Δr20.6 ± 1.0kcal/molTDAsMeot-ner, 1988gas phase; B,M
Quantity Value Units Method Reference Comment
Δr24.3cal/mol*KPHPMSMeot-ner, 1988gas phase; M
Quantity Value Units Method Reference Comment
Δr13.3 ± 1.0kcal/molTDAsMeot-ner, 1988gas phase; B

cyclopentadienide anion + Acetone = (cyclopentadienide anion • Acetone)

By formula: C5H5- + C3H6O = (C5H5- • C3H6O)

Quantity Value Units Method Reference Comment
Δr13.5 ± 1.0kcal/molTDAsMeot-ner, 1988gas phase; B,M
Quantity Value Units Method Reference Comment
Δr21.8cal/mol*KPHPMSMeot-ner, 1988gas phase; M
Quantity Value Units Method Reference Comment
Δr7.0 ± 1.0kcal/molTDAsMeot-ner, 1988gas phase; B

cyclopentadienide anion + 2-Propanol, 2-methyl- = (cyclopentadienide anion • 2-Propanol, 2-methyl-)

By formula: C5H5- + C4H10O = (C5H5- • C4H10O)

Quantity Value Units Method Reference Comment
Δr17.0 ± 1.0kcal/molTDAsMeot-ner, 1988gas phase; B,M
Quantity Value Units Method Reference Comment
Δr32.0cal/mol*KPHPMSMeot-ner, 1988gas phase; M
Quantity Value Units Method Reference Comment
Δr7.4 ± 1.0kcal/molTDAsMeot-ner, 1988gas phase; B

(cyclopentadienide anion • C2D3N) + C2D3N = (cyclopentadienide anion • 2C2D3N)

By formula: (C5H5- • C2D3N) + C2D3N = (C5H5- • 2C2D3N)

Quantity Value Units Method Reference Comment
Δr13.1kcal/molPHPMSMeot-ner, 1988gas phase; CD3CN; M
Quantity Value Units Method Reference Comment
Δr22.8cal/mol*KPHPMSMeot-ner, 1988gas phase; CD3CN; M

cyclopentadienide anion + Methyl Alcohol = (cyclopentadienide anion • Methyl Alcohol)

By formula: C5H5- + CH4O = (C5H5- • CH4O)

Quantity Value Units Method Reference Comment
Δr13.2 ± 1.0kcal/molTDAsMeot-ner, 1988gas phase; B
Quantity Value Units Method Reference Comment
Δr6.9 ± 1.0kcal/molTDAsMeot-ner, 1988gas phase; B

cyclopentadienide anion + Acetonitrile = (cyclopentadienide anion • Acetonitrile)

By formula: C5H5- + C2H3N = (C5H5- • C2H3N)

Quantity Value Units Method Reference Comment
Δr15.5 ± 1.0kcal/molTDAsMeot-ner, 1988gas phase; B
Quantity Value Units Method Reference Comment
Δr8.7 ± 1.0kcal/molTDAsMeot-ner, 1988gas phase; B

(cyclopentadienide anion • Water) + Water = (cyclopentadienide anion • 2Water)

By formula: (C5H5- • H2O) + H2O = (C5H5- • 2H2O)

Quantity Value Units Method Reference Comment
Δr10.0kcal/molPHPMSMeot-ner, 1988gas phase; M
Quantity Value Units Method Reference Comment
Δr17.4cal/mol*KPHPMSMeot-ner, 1988gas phase; M

(cyclopentadienide anion • Acetone) + Acetone = (cyclopentadienide anion • 2Acetone)

By formula: (C5H5- • C3H6O) + C3H6O = (C5H5- • 2C3H6O)

Quantity Value Units Method Reference Comment
Δr9.8kcal/molPHPMSMeot-ner, 1988gas phase; M
Quantity Value Units Method Reference Comment
Δr16.4cal/mol*KPHPMSMeot-ner, 1988gas phase; M

cyclopentadienide anion + C2D3N = (cyclopentadienide anion • C2D3N)

By formula: C5H5- + C2D3N = (C5H5- • C2D3N)

Quantity Value Units Method Reference Comment
Δr15.5kcal/molPHPMSMeot-ner, 1988gas phase; M
Quantity Value Units Method Reference Comment
Δr22.8cal/mol*KPHPMSMeot-ner, 1988gas phase; M

cyclopentadienide anion + CCoO = C6H5CoO-

By formula: C5H5- + CCoO = C6H5CoO-

Quantity Value Units Method Reference Comment
Δr10.20 ± 0.80kcal/molN/ASunderlin and Squires, 1999gas phase; B

cyclopentadienide anion + cobalt = C5H5Co-

By formula: C5H5- + Co = C5H5Co-

Quantity Value Units Method Reference Comment
Δr7.00 ± 0.60kcal/molN/ASunderlin and Squires, 1999gas phase; B

References

Go To: Top, Reaction thermochemistry data, Notes

Data compilation copyright by the U.S. Secretary of Commerce on behalf of the U.S.A. All rights reserved.

Bartmess, Scott, et al., 1979
Bartmess, J.E.; Scott, J.A.; McIver, R.T., Jr., The gas phase acidity scale from methanol to phenol, J. Am. Chem. Soc., 1979, 101, 6047. [all data]

Cumming and Kebarle, 1978
Cumming, J.B.; Kebarle, P., Summary of gas phase measurements involving acids AH. Entropy changes in proton transfer reactions involving negative ions. Bond dissociation energies D(A-H) and electron affinities EA(A), Can. J. Chem., 1978, 56, 1. [all data]

Engelking and Lineberger, 1977
Engelking, P.C.; Lineberger, W.C., Laser photoelectron spectrometry of C5H5-: A determination of the electron affinity and Jahn-Teller coupling in cyclopentadienyl, J. Chem. Phys., 1977, 67, 1412. [all data]

Meot-ner, 1988
Meot-ner, M., The Ionic Hydrogen Bond and Solvation. 7. Interaction Energies of Carbanions with Solvent Molecules, J. Am. Chem. Soc., 1988, 110, 12, 3858, https://doi.org/10.1021/ja00220a022 . [all data]

Sunderlin and Squires, 1999
Sunderlin, L.S.; Squires, R.R., Bond strengths in cyclopentadienyl metal carbonyl anions, Int. J. Mass Spectrom., 1999, 183, 149-161, https://doi.org/10.1016/S1387-3806(98)14230-6 . [all data]


Notes

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