MeO 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

CH3O- + Hydrogen cation = Methyl Alcohol

By formula: CH3O- + H+ = CH4O

Quantity Value Units Method Reference Comment
Δr382. ± 2.kcal/molAVGN/AAverage of 6 values; Individual data points
Quantity Value Units Method Reference Comment
Δr376.02 ± 0.62kcal/molH-TSNee, Osterwalder, et al., 2006gas phase; B
Δr376.04 ± 0.55kcal/molH-TSOsborn, Leahy, et al., 1998gas phase; B
Δr374.0 ± 2.0kcal/molIMREBartmess, Scott, et al., 1979gas phase; The acidity is 1.2 kcal/mol stronger than that from the D-EA cycle, due to the multi-compound fit for the acidity scale.; value altered from reference due to change in acidity scale; B
Δr374.6 ± 2.1kcal/molH-TSHaas and Harrison, 1993gas phase; Both metastable and 50 eV collision energy.; B
Δr375.10 ± 0.60kcal/molTDEqMeot-ner and Sieck, 1986gas phase; Experimental entropy: 21.5 eu, 0.6 less than H2O; B

CH3O- + Methyl Alcohol = (CH3O- • Methyl Alcohol)

By formula: CH3O- + CH4O = (CH3O- • CH4O)

Quantity Value Units Method Reference Comment
Δr29.3 ± 1.0kcal/molTDAsPaul and Kebarle, 1990gas phase; B,M
Δr28.80 ± 0.30kcal/molTDAsMeot-ner and Sieck, 1986gas phase; B,M
Δr29.4 ± 2.5kcal/molTDAsCaldwell, Rozeboom, et al., 1984gas phase; Reanchored to average data from Paul and Kebarle, 1990 and Meot-ner and Sieck, 1986.; value altered from reference due to change in acidity scale; B
Δr19.0 ± 2.0kcal/molN/AMoylan, Dodd, et al., 1985gas phase; B
Quantity Value Units Method Reference Comment
Δr31.8cal/mol*KPHPMSPaul and Kebarle, 1990gas phase; M
Δr26.7cal/mol*KPHPMSMeot-Ner(Mautner), 1986gas phase; n; M
Quantity Value Units Method Reference Comment
Δr20.30kcal/molIMREMustanir, Matsuoka, et al., 2006gas phase; B
Δr19.8 ± 1.0kcal/molTDAsPaul and Kebarle, 1990gas phase; B
Δr20.80 ± 0.50kcal/molTDAsMeot-ner and Sieck, 1986gas phase; B
Δr20.3 ± 1.6kcal/molTDAsCaldwell, Rozeboom, et al., 1984gas phase; Reanchored to average data from Paul and Kebarle, 1990 and Meot-ner and Sieck, 1986.; value altered from reference due to change in acidity scale; B

Free energy of reaction

ΔrG° (kcal/mol) T (K) Method Reference Comment
19.1296.FAMacKay and Bohme, 1978gas phase; From thermochemical cycle,switching reaction(CH3O-)H2O; Meot-Ner(Mautner), 1986; M

CH3O- + Water = (CH3O- • Water)

By formula: CH3O- + H2O = (CH3O- • H2O)

Bond type: Hydrogen bond (negative ion to hydride)

Quantity Value Units Method Reference Comment
Δr25.3 ± 2.2kcal/molCIDTDeTuri and Ervin, 1999gas phase; B
Δr23.9kcal/molPHPMSMeot-Ner(Mautner), 1986gas phase; n; M,B,M
Quantity Value Units Method Reference Comment
Δr22.9cal/mol*KPHPMSMeot-ner and Sieck, 1986gas phase; M
Δr22.9cal/mol*KPHPMSMeot-Ner(Mautner), 1986gas phase; n; M
Quantity Value Units Method Reference Comment
Δr17.00 ± 0.30kcal/molTDAsMeot-ner and Sieck, 1986gas phase; B

Free energy of reaction

ΔrG° (kcal/mol) T (K) Method Reference Comment
15.4296.FAMacKay and Bohme, 1978gas phase; From thermochemical cycle,switching reaction(OH-)H2O, DG>; Meot-Ner(Mautner), 1986; M

(CH3O- • 4294967295Formaldehyde) + Formaldehyde = CH3O-

By formula: (CH3O- • 4294967295CH2O) + CH2O = CH3O-

Quantity Value Units Method Reference Comment
Δr39.90 ± 0.51kcal/molN/ANee, Osterwalder, et al., 2006gas phase; B
Δr40.8 ± 1.1kcal/molTherOsborn, Leahy, et al., 1998gas phase; B
Δr41.8 ± 2.2kcal/molTherBartmess, Scott, et al., 1979gas phase; The acidity is 1.2 kcal/mol stronger than that from the D-EA cycle, due to the multi-compound fit for the acidity scale.; value altered from reference due to change in acidity scale; B

(CH3O- • 2Water) + Water = (CH3O- • 3Water)

By formula: (CH3O- • 2H2O) + H2O = (CH3O- • 3H2O)

Bond type: Hydrogen bond (negative ion to hydride)

Quantity Value Units Method Reference Comment
Δr14.8kcal/molPHPMSMeot-Ner(Mautner), 1986gas phase; n; M
Quantity Value Units Method Reference Comment
Δr24.4cal/mol*KPHPMSMeot-Ner(Mautner), 1986gas phase; n; M

Free energy of reaction

ΔrG° (kcal/mol) T (K) Method Reference Comment
7.9296.FAMacKay and Bohme, 1978gas phase; From thermochemical cycle,switching reaction(OH-)3H2O; Meot-Ner(Mautner), 1986; M

(CH3O- • Water) + Water = (CH3O- • 2Water)

By formula: (CH3O- • H2O) + H2O = (CH3O- • 2H2O)

Bond type: Hydrogen bond (negative ion to hydride)

Quantity Value Units Method Reference Comment
Δr19.2kcal/molPHPMSMeot-Ner(Mautner), 1986gas phase; n; M
Quantity Value Units Method Reference Comment
Δr25.3cal/mol*KPHPMSMeot-Ner(Mautner), 1986gas phase; n; M

Free energy of reaction

ΔrG° (kcal/mol) T (K) Method Reference Comment
8.2296.FAMacKay and Bohme, 1978gas phase; From thermochemical cycle,switching reaction(OH-)2H2O; Meot-Ner(Mautner), 1986; M

CH3O- + Methanol-D4 = C2H4D7O2-

By formula: CH3O- + CD4O = C2H4D7O2-

Quantity Value Units Method Reference Comment
Δr28.3 ± 1.0kcal/molIMREChabinyc and Brauman, 2000gas phase; Original dG=19.4 at 350K; dS based on symmetry alone.; B
Quantity Value Units Method Reference Comment
Δr20.7 ± 1.0kcal/molIMREChabinyc and Brauman, 2000gas phase; Original dG=19.4 at 350K; dS based on symmetry alone.; B

(CH3O- • Water • Methyl Alcohol) + Water = (CH3O- • 2Water • Methyl Alcohol)

By formula: (CH3O- • H2O • CH4O) + H2O = (CH3O- • 2H2O • CH4O)

Bond type: Hydrogen bond (negative ion to hydride)

Quantity Value Units Method Reference Comment
Δr15.2kcal/molPHPMSMeot-Ner(Mautner), 1986gas phase; n; M
Quantity Value Units Method Reference Comment
Δr27.7cal/mol*KPHPMSMeot-Ner(Mautner), 1986gas phase; n; M

(CH3O- • 2Methyl Alcohol) + Water = (CH3O- • Water • 2Methyl Alcohol)

By formula: (CH3O- • 2CH4O) + H2O = (CH3O- • H2O • 2CH4O)

Bond type: Hydrogen bond (negative ion to hydride)

Quantity Value Units Method Reference Comment
Δr13.8kcal/molPHPMSMeot-Ner(Mautner), 1986gas phase; n; M
Quantity Value Units Method Reference Comment
Δr25.0cal/mol*KPHPMSMeot-Ner(Mautner), 1986gas phase; n; M

(CH3O- • Methyl Alcohol) + Water = (CH3O- • Water • Methyl Alcohol)

By formula: (CH3O- • CH4O) + H2O = (CH3O- • H2O • CH4O)

Bond type: Hydrogen bond (negative ion to hydride)

Quantity Value Units Method Reference Comment
Δr17.8kcal/molPHPMSMeot-Ner(Mautner), 1986gas phase; n; M
Quantity Value Units Method Reference Comment
Δr25.9cal/mol*KPHPMSMeot-Ner(Mautner), 1986gas phase; n; M

(CH3O- • 3Water) + Water = (CH3O- • 4Water)

By formula: (CH3O- • 3H2O) + H2O = (CH3O- • 4H2O)

Bond type: Hydrogen bond (negative ion to hydride)

Quantity Value Units Method Reference Comment
Δr11.0kcal/molPHPMSMeot-Ner(Mautner), 1986gas phase; n; M
Quantity Value Units Method Reference Comment
Δr20.0cal/mol*KPHPMSMeot-Ner(Mautner), 1986gas phase; n; M

CH3O- + Fluoroform = C2H4F3O-

By formula: CH3O- + CHF3 = C2H4F3O-

Quantity Value Units Method Reference Comment
Δr23.5 ± 1.0kcal/molIMREChabinyc and Brauman, 1998gas phase; B
Quantity Value Units Method Reference Comment
Δr16.6 ± 1.0kcal/molIMREChabinyc and Brauman, 1998gas phase; B

(CH3O- • Water) + Methyl Alcohol = (CH3O- • Methyl Alcohol • Water)

By formula: (CH3O- • H2O) + CH4O = (CH3O- • CH4O • H2O)

Free energy of reaction

ΔrG° (kcal/mol) T (K) Method Reference Comment
13.7296.FAMacKay and Bohme, 1978gas phase; From thermochemical cycle,switching reaction(CH3O-)2H2O; Meot-Ner(Mautner), 1986; M

CH3O- + Boron trifluoride = (CH3O- • Boron trifluoride)

By formula: CH3O- + BF3 = (CH3O- • BF3)

Quantity Value Units Method Reference Comment
Δr>22.0 ± 2.0kcal/molIMRBBlair, Isolani, et al., 1973gas phase; MeOH..MeO- + BF3 ->. Computations indicate dHaff ca. 80 kcal/mol; B

(CH3O- • 2Methyl Alcohol) + Methyl Alcohol = (CH3O- • 3Methyl Alcohol)

By formula: (CH3O- • 2CH4O) + CH4O = (CH3O- • 3CH4O)

Quantity Value Units Method Reference Comment
Δr15.0kcal/molPHPMSMeot-Ner(Mautner), 1986gas phase; n; M
Quantity Value Units Method Reference Comment
Δr26.3cal/mol*KPHPMSMeot-Ner(Mautner), 1986gas phase; n; M

(CH3O- • 3Methyl Alcohol) + Methyl Alcohol = (CH3O- • 4Methyl Alcohol)

By formula: (CH3O- • 3CH4O) + CH4O = (CH3O- • 4CH4O)

Quantity Value Units Method Reference Comment
Δr11.4kcal/molPHPMSMeot-Ner(Mautner), 1986gas phase; n; M
Quantity Value Units Method Reference Comment
Δr22.4cal/mol*KPHPMSMeot-Ner(Mautner), 1986gas phase; n; M

(CH3O- • Methyl Alcohol) + Methyl Alcohol = (CH3O- • 2Methyl Alcohol)

By formula: (CH3O- • CH4O) + CH4O = (CH3O- • 2CH4O)

Quantity Value Units Method Reference Comment
Δr21.4kcal/molPHPMSMeot-Ner(Mautner), 1986gas phase; n; M
Quantity Value Units Method Reference Comment
Δr27.8cal/mol*KPHPMSMeot-Ner(Mautner), 1986gas phase; n; M

CH3O- + Trifluorophenylsilane = C7H8F3OSi-

By formula: CH3O- + C6H5F3Si = C7H8F3OSi-

Quantity Value Units Method Reference Comment
Δr76.6 ± 5.9kcal/molCIDTKrouse, Lardin, et al., 2003gas phase; B

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 compiled by: John E. Bartmess

Electron affinity of neutral species

EAneutral (eV) Method Reference Comment
1.5690 ± 0.0019LPESNee, Osterwalder, et al., 2006 
1.5720 ± 0.0040LPESRamond, Davico, et al., 2000 
1.5680 ± 0.0050LPESOsborn, Leahy, et al., 1998 
1.685 ± 0.094D-EABartmess, Scott, et al., 1979The acidity is 1.2 kcal/mol stronger than that from the D-EA cycle, due to the multi-compound fit for the acidity scale.; value altered from reference due to change in acidity scale
1.570 ± 0.022LPESEngleking, Ellison, et al., 1978Confirmed by high level calculations: Hiraoka, Shimizu, et al., 1995
1.591 ± 0.040PDJanousek, Zimmerman, et al., 1978 
<1.591 ± 0.039PDReed and Brauman, 1975 
2.59998EIAETsuda and Hamill, 1964From MeOMe
0.3816SIPage and Goode, 1969The Magnetron method, lacking mass analysis, is not considered reliable.

Protonation reactions

CH3O- + Hydrogen cation = Methyl Alcohol

By formula: CH3O- + H+ = CH4O

Quantity Value Units Method Reference Comment
Δr382. ± 2.kcal/molAVGN/AAverage of 6 values; Individual data points
Quantity Value Units Method Reference Comment
Δr376.02 ± 0.62kcal/molH-TSNee, Osterwalder, et al., 2006gas phase
Δr376.04 ± 0.55kcal/molH-TSOsborn, Leahy, et al., 1998gas phase
Δr374.0 ± 2.0kcal/molIMREBartmess, Scott, et al., 1979gas phase; The acidity is 1.2 kcal/mol stronger than that from the D-EA cycle, due to the multi-compound fit for the acidity scale.; value altered from reference due to change in acidity scale
Δr374.6 ± 2.1kcal/molH-TSHaas and Harrison, 1993gas phase; Both metastable and 50 eV collision energy.
Δr375.10 ± 0.60kcal/molTDEqMeot-ner and Sieck, 1986gas phase; Experimental entropy: 21.5 eu, 0.6 less than H2O

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.

Nee, Osterwalder, et al., 2006
Nee, M.J.; Osterwalder, A.; Zhou, J.; Neumark, D.M., Slow electron velocity-map imaging photoelectron spectra of the methoxide anion, J. Chem. Phys., 2006, 125, 1, 014306, https://doi.org/10.1063/1.2212411 . [all data]

Osborn, Leahy, et al., 1998
Osborn, D.L.; Leahy, D.J.; Kim, E.H.; deBeer, E.; Neumark, D.M., Photoelectron spectroscopy of CH3O- and CD3O-, Chem. Phys. Lett., 1998, 292, 4-6, 651-655, https://doi.org/10.1016/S0009-2614(98)00717-9 . [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]

Haas and Harrison, 1993
Haas, M.J.; Harrison, A.G., The Fragmentation of Proton-Bound Cluster Ions and the Gas-Phase Acidities of Alcohols, Int. J. Mass Spectrom. Ion Proc., 1993, 124, 2, 115, https://doi.org/10.1016/0168-1176(93)80003-W . [all data]

Meot-ner and Sieck, 1986
Meot-ner, M.; Sieck, L.W., Relative acidities of water and methanol, and the stabilities of the dimer adducts, J. Phys. Chem., 1986, 90, 6687. [all data]

Paul and Kebarle, 1990
Paul, G.J.C.; Kebarle, P., Thermodynamics of the Association Reactions OH- - H2O = HOHOH- and CH3O- - CH3OH = CH3OHOCH3- in the Gas Phase, J. Phys. Chem., 1990, 94, 12, 5184, https://doi.org/10.1021/j100375a076 . [all data]

Caldwell, Rozeboom, et al., 1984
Caldwell, G.; Rozeboom, M.D.; Kiplinger, J.P.; Bartmess, J.E., Anion-alcohol hydrogen bond strengths in the gas phase, J. Am. Chem. Soc., 1984, 106, 4660. [all data]

Moylan, Dodd, et al., 1985
Moylan, C.R.; Dodd, J.A.; Brauman, J.I., Electron photodetachment spectroscopy of Sslvated anions. A probe of structure and energetics, Chem. Phys. Lett., 1985, 118, 38. [all data]

Meot-Ner(Mautner), 1986
Meot-Ner(Mautner), M., Comparative Stabilities of Cationic and Anionic Hydrogen-Bonded Networks. Mixed Clusters of Water-Methanol, J. Am. Chem. Soc., 1986, 108, 20, 6189, https://doi.org/10.1021/ja00280a014 . [all data]

Mustanir, Matsuoka, et al., 2006
Mustanir; Matsuoka, M.; Mishima, M.; Koch, H., Stability of complexes of phenylacetylides and benzyl alkoxides with methanol in the gas phase. Acid-base correlation in the ionic hydrogen-bond strength, Bull. Chem. Soc. Japan, 2006, 79, 7, 1118-1125, https://doi.org/10.1246/bcsj.79.1118 . [all data]

MacKay and Bohme, 1978
MacKay, G.I.; Bohme, D.K., Proton-Transfer Reactions in Nitromethane at 297K, Int. J. Mass Spectrom. Ion Phys., 1978, 26, 4, 327, https://doi.org/10.1016/0020-7381(78)80052-7 . [all data]

DeTuri and Ervin, 1999
DeTuri, V.F.; Ervin, K.M., Competitive threshold collision-induced dissociation: Gas-phase acidities and bond dissociation energies for a series of alcohols, J. Phys. Chem. A, 1999, 103, 35, 6911-6920, https://doi.org/10.1021/jp991459m . [all data]

Chabinyc and Brauman, 2000
Chabinyc, M.L.; Brauman, J.I., Unusual ionic hydrogen bonds: Complexes of acetylides and fluoroform, J. Am. Chem. Soc., 2000, 122, 36, 8739-8745, https://doi.org/10.1021/ja000806z . [all data]

Chabinyc and Brauman, 1998
Chabinyc, M.L.; Brauman, J.I., Acidity, basicity, and the stability of hydrogen bonds: Complexes of RO-+HCF3, J. Am. Chem. Soc., 1998, 120, 42, 10863-10870, https://doi.org/10.1021/ja9817592 . [all data]

Blair, Isolani, et al., 1973
Blair, L.K.; Isolani, P.C.; Riveros, J.M., Formation, reactivity, and relative stability of clustered alkoxide ions by ICR spectroscopy, J. Am. Chem. Soc., 1973, 95, 1057. [all data]

Krouse, Lardin, et al., 2003
Krouse, I.H.; Lardin, H.A.; Wenthold, P.G., Gas-phase ion chemistry and ion thermochemistry of phenyltrifluorosilane, Int. J. Mass Spectrom., 2003, 227, 3, 303-314, https://doi.org/10.1016/S1387-3806(03)00080-0 . [all data]

Ramond, Davico, et al., 2000
Ramond, T.M.; Davico, G.E.; Schwartz, R.L.; Lineberger, W.C., Vibronic structure of alkoxy radicals via photoelectron spectroscopy, J. Chem. Phys., 2000, 112, 3, 1158-1169, https://doi.org/10.1063/1.480767 . [all data]

Engleking, Ellison, et al., 1978
Engleking, P.C.; Ellison, G.B.; Lineberger, W.C., Laser photodetachment electron spectrometry of methoxide, deuteromethoxide, and thiomethoxide: Electron affinities and vibrational structure of CH3O, and CH3S, J. Chem. Phys., 1978, 69, 1826. [all data]

Hiraoka, Shimizu, et al., 1995
Hiraoka, K.; Shimizu, A.; Minamitsu, A.; Nasu, M.; Fujimaki, S.; Yamabe, S., The small binding energies of the negative cluster ions: SF5-(SF6)1, SF6-(SF6)1 and F-(SF6)n (n=1 and 2), in the gas phase, Chem. Phys. Lett., 1995, 241, 5-6, 623, https://doi.org/10.1016/0009-2614(95)00676-U . [all data]

Janousek, Zimmerman, et al., 1978
Janousek, B.K.; Zimmerman, A.H.; Reed, K.J.; Brauman, J.I., Electron detachment from aliphatic molecular anions. Gas phase electron affinites of methoxyl, tert-butoxyl, and neopentoxyl radicals, J. Am. Chem. Soc., 1978, 100, 6142. [all data]

Reed and Brauman, 1975
Reed, K.J.; Brauman, J.I., Electron affinities of alkoxy radicals and the bond dissociation energies in aliphatic alcohols, J. Am. Chem. Soc., 1975, 97, 1625. [all data]

Tsuda and Hamill, 1964
Tsuda, S.; Hamill, W.H., Ionization Efficiency Measurements by the Retarding Potential Difference Method, Adv. Mass Spectrom., 1964, 3, 249. [all data]

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


Notes

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