Methylene, difluoro-

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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 by: John E. Bartmess

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Individual Reactions

(CF3- • 4294967295Methylene, difluoro-) + Methylene, difluoro- = CF3-

By formula: (CF3- • 4294967295CF2) + CF2 = CF3-

Quantity Value Units Method Reference Comment
Δr49.8 ± 2.4kcal/molN/ADeyerl, Alconcel, et al., 2001gas phase; Adiabatic EA, from vibrational structure of spectrum
Δr50.9 ± 2.9kcal/molN/ABartmess, Scott, et al., 1979gas phase; Paulino and Squires, 1991 suggests that this acidity may be too weak by ca. 5 kcal/mol. However, G2 calcn(JEB) give ΔHacid=379.9, ΔGacid=372.0; value altered from reference due to change in acidity scale
Δr55.9 ± 2.7kcal/molCIDTPaulino and Squires, 1991gas phase; Neutral heat is based on a fluoroform acidity that may be too weak by up to 5 kcal/mol

(CAS Reg. No. 53959-80-1 • 4294967295Methylene, difluoro-) + Methylene, difluoro- = CAS Reg. No. 53959-80-1

By formula: (CAS Reg. No. 53959-80-1 • 4294967295CF2) + CF2 = CAS Reg. No. 53959-80-1

Quantity Value Units Method Reference Comment
Δr<8.00kcal/molCIDTPaulino and Squires, 1991, 2gas phase; Probably CF2..Cl-, non-covalent.

Gas phase ion energetics 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 evaluated as indicated in comments:
HL - Edward P. Hunter and Sharon G. Lias
L - Sharon G. Lias

Data compiled as indicated in comments:
LL - Sharon G. Lias and Joel F. Liebman
LLK - Sharon G. Lias, Rhoda D. Levin, and Sherif A. Kafafi
RDSH - Henry M. Rosenstock, Keith Draxl, Bruce W. Steiner, and John T. Herron
B - John E. Bartmess

View reactions leading to CF2+ (ion structure unspecified)

Quantity Value Units Method Reference Comment
IE (evaluated)11.44 ± 0.03eVN/AN/AL
Quantity Value Units Method Reference Comment
Proton affinity (review)183.kcal/molN/AHunter and Lias, 1998HL
Quantity Value Units Method Reference Comment
Gas basicity175.1kcal/molN/AHunter and Lias, 1998HL

Electron affinity determinations

EA (eV) Method Reference Comment
0.180 ± 0.020LPESSchwartz, Davico, et al., 1999Neutral carbene triplet 54±3 kcal/mol above singlet; B
0.1790 ± 0.0050LPESMurray, Leopold, et al., 1988Singlet-triplet splitting in neutral > 50 kcal/mol; B
0.07 ± 0.15D-EABorn, Ingemann, et al., 1994B
<1.30 ± 0.80EIAEHarland and Thynne, 1972From C2F4. G3MP2B3 calculations indicate an EA of ca. 0.4 eV.; B
>0.20047EIAEThynne and MacNeil, 1970From C2F4. G3MP2B3 calculations indicate an EA of ca. 0.4 eV.; B
2.64955SIPage and Goode, 1969The Magnetron method, lacking mass analysis, is not considered reliable.; B

Ionization energy determinations

IE (eV) Method Reference Comment
11.445 ± 0.025PIBuckley, Johnson, et al., 1995LL
15.2EIGoto, Nakamura, et al., 1994LL
11.5 ± 0.4EITarnovsky and Becker, 1993LL
11.4 ± 0.3EIHildenbrand, 1975LLK
11.5 ± 0.1EIHildenbrand, 1975LLK
11.42 ± 0.01PEDyke, Golob, et al., 1974LLK
9.74DERReinke, Kraessig, et al., 1973LLK
11.54 ± 0.10EIHildenbrand, 1973LLK
11.7 ± 0.2EIEhlert, 1969RDSH
11.8 ± 0.3EIZmbov, Uy, et al., 1968RDSH
11.9 ± 0.1EIPottie, 1965RDSH
11.7 ± 0.1EIFisher, Homer, et al., 1965RDSH

Appearance energy determinations

Ion AE (eV) Other Products MethodReferenceComment
CF+18.5FEIGoto, Nakamura, et al., 1994LL
CF+14.6 ± 0.4FEITarnovsky, Kurunczi, et al., 1993LL
F+31.4 ± 1.0CF+EITarnovsky, Kurunczi, et al., 1993LL

References

Go To: Top, Reaction thermochemistry data, Gas phase ion energetics data, Notes

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

Deyerl, Alconcel, et al., 2001
Deyerl, H.J.; Alconcel, L.S.; Continetti, R.E., Photodetachment imaging studies of the electron affinity of CF3, J. Phys. Chem. A, 2001, 105, 3, 552-557, https://doi.org/10.1021/jp003137k . [all data]

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]

Paulino and Squires, 1991
Paulino, J.A.; Squires, R.R., Carbene Thermochemistry from Collision-Induced Dissociation Threshold Energy Measurements - The Heats of Formation of X1A1 CF2 and X1A1 CCl2, J. Am. Chem. Soc., 1991, 113, 15, 5573, https://doi.org/10.1021/ja00015a009 . [all data]

Paulino and Squires, 1991, 2
Paulino, J.A.; Squires, R.R., Carbene Anion Complexes - Unusual Structural and Thermochemical Features of alpha-Halocarbanions in the Gas Phase, J. Am. Chem. Soc., 1991, 113, 5, 1845, https://doi.org/10.1021/ja00005a067 . [all data]

Hunter and Lias, 1998
Hunter, E.P.; Lias, S.G., Evaluated Gas Phase Basicities and Proton Affinities of Molecules: An Update, J. Phys. Chem. Ref. Data, 1998, 27, 3, 413-656, https://doi.org/10.1063/1.556018 . [all data]

Schwartz, Davico, et al., 1999
Schwartz, R.L.; Davico, G.E.; Ramond, T.M.; Lineberger, W.C., Singlet-triplet splittings in CX2 (X = F, Cl, Br, I) dihalocarbenes via negative ion photoelectron spectroscopy, J. Phys. Chem. A, 1999, 103, 41, 8213-8221, https://doi.org/10.1021/jp992214c . [all data]

Murray, Leopold, et al., 1988
Murray, K.K.; Leopold, D.G.; Miller, T.M.; Lineberger, W.C., Photoelectron Spectroscopy of the Halocarbene Anions HCF-, HCCl-, HCBr-, HCI-, CF2-, and CCl2-, J. Chem. Phys., 1988, 89, 9, 5442, https://doi.org/10.1063/1.455596 . [all data]

Born, Ingemann, et al., 1994
Born, M.; Ingemann, S.; Nibbering, N.M.M., Heats of formation of mono-halogen-substituted carbenes. Stability and reactivity of CHX(center dot-) (X=F, Cl, Pr, and I) radical anions, J. Am. Chem. Soc., 1994, 116, 16, 7210, https://doi.org/10.1021/ja00095a025 . [all data]

Harland and Thynne, 1972
Harland, P.W.; Thynne, J.C.J., Ionisation of perfluorocyclobutane by electron impact, Int. J. Mass Spectrom. Ion Phys., 1972, 10, 11. [all data]

Thynne and MacNeil, 1970
Thynne, J.C.J.; MacNeil, K.A.G., Ionisation of Tetrafluoroethylene by Electron Impact, Int. J. Mass Spectrom. Ion Phys., 1970, 5, 3-4, 329, https://doi.org/10.1016/0020-7381(70)80026-2 . [all data]

Page and Goode, 1969
Page, F.M.; Goode, G.C., Negative Ions and the Magnetron., Wiley, NY, 1969. [all data]

Buckley, Johnson, et al., 1995
Buckley, T.J.; Johnson, R.D.; Huie, R.E.; Zhang, Z.; Kuo, S.C.; Klemm, R.B., Ionization energies, appearance energies, and thermochemistry of CF2O and FCO, J. Phys. Chem., 1995, 99, 4879. [all data]

Goto, Nakamura, et al., 1994
Goto, M.; Nakamura, K.; Toyoda, H.; Sugai, H., Cross section measurements for electron-impact dissociation of CHF3 into neutral and ionic fragments, Jpn. J. Appl. Phys. Part 1, 1994, 33, 3602. [all data]

Tarnovsky and Becker, 1993
Tarnovsky, V.; Becker, K., Absolute partial cross sections for the parent ionization of the CFx (x = 1-3) free radicals by electron impact, J. Chem. Phys., 1993, 98, 7868. [all data]

Hildenbrand, 1975
Hildenbrand, D.L., Vertical ionization potential of the CF2 radical, Chem. Phys. Lett., 1975, 32, 30. [all data]

Dyke, Golob, et al., 1974
Dyke, J.M.; Golob, L.; Jonathan, N.; Morris, A.; Okuda, M., Vacuum ultraviolet photoelectron spectroscopy of transient species. Part 4. Difluoromethylene and ozone, J. Chem. Soc. Faraday Trans. 2, 1974, 70, 1828. [all data]

Reinke, Kraessig, et al., 1973
Reinke, D.; Kraessig, R.; Baumgartel, H., Photoreactions of small organic molecules, Z. Naturforsch. A:, 1973, 28, 1021. [all data]

Hildenbrand, 1973
Hildenbrand, D.L., Mass spectrometric studies of some gaseous sulfur fluorides, J. Phys. Chem., 1973, 77, 897. [all data]

Ehlert, 1969
Ehlert, T.C., Bonding in C1 and C2 fluorides, J. Phys. Chem., 1969, 73, 949. [all data]

Zmbov, Uy, et al., 1968
Zmbov, K.F.; Uy, M.; Margrave, J.L., Mass spectrometric study of the high-temperature equilibrium C2F4 = 2CF2 and the heat of formation of the CF2 radical, J. Am. Chem. Soc., 1968, 90, 5090. [all data]

Pottie, 1965
Pottie, R.F., Ionization potential and heat of formation of the difluoromethylene radical, J. Chem. Phys., 1965, 42, 2607. [all data]

Fisher, Homer, et al., 1965
Fisher, I.P.; Homer, J.B.; Lossing, F.P., Free radicals by mass spectrometry. XXXIII. Ionization potentials of CF2, CF3CF2, CF3CH2, n-C3F7, and i-C3F7 radicals, J. Am. Chem. Soc., 1965, 87, 957. [all data]

Tarnovsky, Kurunczi, et al., 1993
Tarnovsky, V.; Kurunczi, P.; Rogozhnikov, D.; Becker, K., Absolute cross sections for the dissociative electron impact ionization of the CFx (x=1-3) free radicals, Int. J. Mass Spectrom. Ion Processes, 1993, 128, 181. [all data]


Notes

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