Borane, trimethyl-
- Formula: C3H9B
- Molecular weight: 55.915
- IUPAC Standard InChIKey: WXRGABKACDFXMG-UHFFFAOYSA-N
- CAS Registry Number: 593-90-8
- Chemical structure:
This structure is also available as a 2d Mol file - Other names: Trimethylborane; Trimethylboron; (CH3)3B
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Gas phase ion energetics data
Go To: Top, Ion clustering data, Mass spectrum (electron ionization), References, Notes
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
LLK - Sharon G. Lias, Rhoda D. Levin, and Sherif A. Kafafi
RDSH - Henry M. Rosenstock, Keith Draxl, Bruce W. Steiner, and John T. Herron
Ionization energy determinations
IE (eV) | Method | Reference | Comment |
---|---|---|---|
10.4 | PI | Holliday, Reade, et al., 1971 | LLK |
8.8 ± 0.2 | EI | Law and Margrave, 1956 | RDSH |
10.69 | PE | Berger, Kroner, et al., 1976 | Vertical value; LLK |
10.68 | PE | Barker, Lappert, et al., 1975 | Vertical value; LLK |
10.69 | PE | Fuss and Bock, 1974 | Vertical value; LLK |
Appearance energy determinations
Ion | AE (eV) | Other Products | Method | Reference | Comment |
---|---|---|---|---|---|
B+ | 23.1 ± 0.3 | ? | EI | Law and Margrave, 1956 | RDSH |
CH3+ | 15.1 ± 0.3 | ? | EI | Law and Margrave, 1956 | RDSH |
CH3B+ | 17.0 ± 0.5 | ? | EI | Law and Margrave, 1956 | RDSH |
C2H6B+ | 10.3 ± 0.2 | CH3 | EI | Law and Margrave, 1956 | RDSH |
De-protonation reactions
C3H8B- + =
By formula: C3H8B- + H+ = C3H9B
Quantity | Value | Units | Method | Reference | Comment |
---|---|---|---|---|---|
ΔrH° | 366.2 ± 6.1 | kcal/mol | G+TS | Murphy and Beauchamp, 1976 | gas phase; Between AsH3,PH3; value altered from reference due to change in acidity scale; B |
Quantity | Value | Units | Method | Reference | Comment |
ΔrG° | 358.9 ± 6.0 | kcal/mol | IMRB | Murphy and Beauchamp, 1976 | gas phase; Between AsH3,PH3; value altered from reference due to change in acidity scale; B |
Ion clustering data
Go To: Top, Gas phase ion energetics data, Mass spectrum (electron ionization), References, Notes
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
Note: Please consider using the reaction search for this species. This page allows searching of all reactions involving this species. Searches may be limited to ion clustering reactions. A general reaction search form is also available.
Clustering reactions
By formula: F- + C3H9B = (F- • C3H9B)
Quantity | Value | Units | Method | Reference | Comment |
---|---|---|---|---|---|
ΔrH° | 58.50 | kcal/mol | IMRB | Murphy and Beauchamp, 1977 | gas phase; MeSiF3>Me3B>SF4; B |
ΔrH° | 47.2 ± 2.0 | kcal/mol | IMRE | Larson and McMahon, 1985 | gas phase; These relative affinities are ca. 10 kcal/mol weaker than threshold values (see Wenthold and Squires, 1995) for donors greater than ca. 27 kcal/mol in free energy. This discrepancy has not yet been resolved, though the stronger value appears preferable.; B,M |
Quantity | Value | Units | Method | Reference | Comment |
ΔrS° | 25. | cal/mol*K | N/A | Larson and McMahon, 1985 | gas phase; switching reaction,Thermochemical ladder(F-)H2O, Entropy change calculated or estimated; Arshadi, Yamdagni, et al., 1970; M |
Quantity | Value | Units | Method | Reference | Comment |
ΔrG° | 39.7 ± 2.0 | kcal/mol | IMRE | Larson and McMahon, 1985 | gas phase; These relative affinities are ca. 10 kcal/mol weaker than threshold values (see Wenthold and Squires, 1995) for donors greater than ca. 27 kcal/mol in free energy. This discrepancy has not yet been resolved, though the stronger value appears preferable.; B,M |
Mass spectrum (electron ionization)
Go To: Top, Gas phase ion energetics data, Ion clustering data, References, Notes
Data compilation copyright by the U.S. Secretary of Commerce on behalf of the U.S.A. All rights reserved.
Data compiled by: NIST Mass Spectrometry Data Center, William E. Wallace, director
Spectrum
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Additional Data
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Due to licensing restrictions, this spectrum cannot be downloaded.
Owner | NIST Mass Spectrometry Data Center Collection (C) 2014 copyright by the U.S. Secretary of Commerce on behalf of the United States of America. All rights reserved. |
---|---|
Origin | CCC 0004 |
NIST MS number | 108 |
References
Go To: Top, Gas phase ion energetics data, Ion clustering data, Mass spectrum (electron ionization), Notes
Data compilation copyright by the U.S. Secretary of Commerce on behalf of the U.S.A. All rights reserved.
Holliday, Reade, et al., 1971
Holliday, A.K.; Reade, W.; Johnstone, R.A.W.; Neville, A.F.,
Photo-electron spectrum of trivinylboron,
Chem. Commun., 1971, 51. [all data]
Law and Margrave, 1956
Law, R.W.; Margrave, J.L.,
Mass spectrometer appearance potentials for positive ion fragments from BF3, B(CH3)3, B(C2H5)3, B(OCH3)3, and HB(OCH3)2,
J. Chem. Phys., 1956, 25, 1086. [all data]
Berger, Kroner, et al., 1976
Berger, H.-O.; Kroner, J.; Noth, H.,
Die borhalogen-bindung in Methylhalogenboranen: Photoelektronenspektren und ab initio-Rechnungen,
Chem. Ber., 1976, 109, 2266. [all data]
Barker, Lappert, et al., 1975
Barker, G.K.; Lappert, M.F.; Pedley, J.B.; Sharp, G.J.; Westwood, N.P.C.,
Bonding studies of boron and the group 3-5 elements. Part XV. He(I) photoelectron spectra of monomeric group 3 tri-halide, trimethyl, and mixed halogenomethyl species,
J. Chem. Soc. Dalton Trans., 1975, 1765. [all data]
Fuss and Bock, 1974
Fuss, W.; Bock, H.,
Photoelectron spectra and molecular properties. XXXVI. (H3C)3B, (H3C)2BF, (H3C)2BN(CH3)2, and (H3C)2CC(CH3)2: The use of ionization potentials in assigning UV spectra,
J. Chem. Phys., 1974, 61, 1613. [all data]
Murphy and Beauchamp, 1976
Murphy, M.K.; Beauchamp, J.L.,
Acid-base properties and gas-phase ion chemistry of (CH3)3B,
J. Am. Chem. Soc., 1976, 98, 1433. [all data]
Murphy and Beauchamp, 1977
Murphy, M.K.; Beauchamp, J.L.,
Fluorine and Alkyl Substituent Effects on Gas-Phase Lewis Acidities of Boranes by ICR Spectroscopy,
Inorg. Chem., 1977, 16, 2437. [all data]
Larson and McMahon, 1985
Larson, J.W.; McMahon, T.B.,
Fluoride and chloride affinities of the main group oxides, fluorides, oxofluorides, and alkyls. Quantitative scales of lewis acidities from ICR halide exchange equilibria,
J. Am. Chem. Soc., 1985, 107, 766. [all data]
Wenthold and Squires, 1995
Wenthold, P.G.; Squires, R.R.,
Bond dissociation energies of F2(-) and HF2(-). A gas-phase experimental and G2 theoretical study,
J. Phys. Chem., 1995, 99, 7, 2002, https://doi.org/10.1021/j100007a034
. [all data]
Arshadi, Yamdagni, et al., 1970
Arshadi, M.; Yamdagni, R.; Kebarle, P.,
Hydration of Halide Negative Ions in the Gas Phase. II. Comparison of Hydration Energies for the Alkali Positive and Halide Negative Ions,
J. Phys. Chem., 1970, 74, 7, 1475, https://doi.org/10.1021/j100702a014
. [all data]
Notes
Go To: Top, Gas phase ion energetics data, Ion clustering data, Mass spectrum (electron ionization), References
- Symbols used in this document:
AE Appearance energy ΔrG° Free energy of reaction at standard conditions ΔrH° Enthalpy of reaction at standard conditions ΔrS° Entropy of reaction at standard conditions - Data from NIST Standard Reference Database 69: NIST Chemistry WebBook
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