C-H bond dissociation energy of malononitrile

Daniel J. Goebbert; Luis Velarde; Dmitry Khuseynov; Andrei Sanov

doi:10.1021/jz900379t

C-H bond dissociation energy of malononitrile

Daniel J. Goebbert, Luis Velarde, Dmitry Khuseynov, Andrei Sanov

Research output: Contribution to journal › Article › peer-review

34 Scopus citations

Abstract

The C-H bond dissociation energies of closed-shell molecules decrease with increasing stability of the resulting radicals. From the electron affinity of the dicyanomethyl radical, •CH(CN)₂, EA[•CH(CN) ₂]=2.88± 0.01 eV, measured by photoelectron imaging of the CH(CN)₂ ^- anion, and the acidity/electron affinity thermodynamic cycle, we obtained the C-H bond dissociation enthalpy of malononitrile, CH₂(CN)₂, DH₂₉₈[H-CH(CN) ₂]=87 ± 2 kcal/mol. This result is compared to the corresponding value for acetonitrile, DH₂₉₈(H-CH2CN)=93 ± 2 kcal/mol, determined from a similar measurement of EA(•CH₂CN) = 1.53 ( 0.01 eV. The relative weakness of the C-H bonds in malononitrile and acetonitrile, compared to most closed-shell neutral organic molecules, is attributed to π-resonance stabilization of the unpaired electrons in •CH(CN)₂ and •CH₂CN.

Original language	English (US)
Pages (from-to)	792-795
Number of pages	4
Journal	Journal of Physical Chemistry Letters
Volume	1
Issue number	4
DOIs	https://doi.org/10.1021/jz900379t
State	Published - Feb 18 2010

Keywords

Kinetics
Spectroscopy

ASJC Scopus subject areas

General Materials Science
Physical and Theoretical Chemistry

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10.1021/jz900379t

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@article{de75bb1d52e84920b83c1d978c431bc7,

title = "C-H bond dissociation energy of malononitrile",

abstract = "The C-H bond dissociation energies of closed-shell molecules decrease with increasing stability of the resulting radicals. From the electron affinity of the dicyanomethyl radical, •CH(CN)2, EA[•CH(CN) 2]=2.88± 0.01 eV, measured by photoelectron imaging of the CH(CN)2 - anion, and the acidity/electron affinity thermodynamic cycle, we obtained the C-H bond dissociation enthalpy of malononitrile, CH2(CN)2, DH298[H-CH(CN) 2]=87 ± 2 kcal/mol. This result is compared to the corresponding value for acetonitrile, DH298(H-CH2CN)=93 ± 2 kcal/mol, determined from a similar measurement of EA(•CH2CN) = 1.53 ( 0.01 eV. The relative weakness of the C-H bonds in malononitrile and acetonitrile, compared to most closed-shell neutral organic molecules, is attributed to π-resonance stabilization of the unpaired electrons in •CH(CN)2 and •CH2CN.",

keywords = "Kinetics, Spectroscopy",

author = "Goebbert, {Daniel J.} and Luis Velarde and Dmitry Khuseynov and Andrei Sanov",

year = "2010",

month = feb,

day = "18",

doi = "10.1021/jz900379t",

language = "English (US)",

volume = "1",

pages = "792--795",

journal = "Journal of Physical Chemistry Letters",

issn = "1948-7185",

publisher = "American Chemical Society",

number = "4",

}

TY - JOUR

T1 - C-H bond dissociation energy of malononitrile

AU - Goebbert, Daniel J.

AU - Velarde, Luis

AU - Khuseynov, Dmitry

AU - Sanov, Andrei

PY - 2010/2/18

Y1 - 2010/2/18

N2 - The C-H bond dissociation energies of closed-shell molecules decrease with increasing stability of the resulting radicals. From the electron affinity of the dicyanomethyl radical, •CH(CN)2, EA[•CH(CN) 2]=2.88± 0.01 eV, measured by photoelectron imaging of the CH(CN)2 - anion, and the acidity/electron affinity thermodynamic cycle, we obtained the C-H bond dissociation enthalpy of malononitrile, CH2(CN)2, DH298[H-CH(CN) 2]=87 ± 2 kcal/mol. This result is compared to the corresponding value for acetonitrile, DH298(H-CH2CN)=93 ± 2 kcal/mol, determined from a similar measurement of EA(•CH2CN) = 1.53 ( 0.01 eV. The relative weakness of the C-H bonds in malononitrile and acetonitrile, compared to most closed-shell neutral organic molecules, is attributed to π-resonance stabilization of the unpaired electrons in •CH(CN)2 and •CH2CN.

AB - The C-H bond dissociation energies of closed-shell molecules decrease with increasing stability of the resulting radicals. From the electron affinity of the dicyanomethyl radical, •CH(CN)2, EA[•CH(CN) 2]=2.88± 0.01 eV, measured by photoelectron imaging of the CH(CN)2 - anion, and the acidity/electron affinity thermodynamic cycle, we obtained the C-H bond dissociation enthalpy of malononitrile, CH2(CN)2, DH298[H-CH(CN) 2]=87 ± 2 kcal/mol. This result is compared to the corresponding value for acetonitrile, DH298(H-CH2CN)=93 ± 2 kcal/mol, determined from a similar measurement of EA(•CH2CN) = 1.53 ( 0.01 eV. The relative weakness of the C-H bonds in malononitrile and acetonitrile, compared to most closed-shell neutral organic molecules, is attributed to π-resonance stabilization of the unpaired electrons in •CH(CN)2 and •CH2CN.

KW - Kinetics

KW - Spectroscopy

UR - http://www.scopus.com/inward/record.url?scp=77749291759&partnerID=8YFLogxK

UR - http://www.scopus.com/inward/citedby.url?scp=77749291759&partnerID=8YFLogxK

U2 - 10.1021/jz900379t

DO - 10.1021/jz900379t

M3 - Article

AN - SCOPUS:77749291759

SN - 1948-7185

VL - 1

SP - 792

EP - 795

JO - Journal of Physical Chemistry Letters

JF - Journal of Physical Chemistry Letters

IS - 4

ER -

C-H bond dissociation energy of malononitrile

Abstract

Keywords

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