Internal bond rotation in substituted methyl radicals, H2B-CH2, H3C-CH2, H2N-CH2, and HO-CH2: Hardness profiles

Tadafumi Uchimaru, Asit K. Chandra, Shun Ichi Kawahara, Kazunari Matsumura, Seiji Tsuzuki, Masuhiro Mikami

Research output: Contribution to journalArticle

17 Citations (Scopus)

Abstract

The energy profiles for the internal bond rotation of substituted methyl radicals, X-CH2 (X = BH2, CH3, NH2, and OH) were examined with B3LYP/6-31G(d) calculations. Energy evaluation of each point along the rotational coordinate was also carried out with single-point calculation at the computational levels of B3LYP/ 6-311+G(2df,p) and QCISD(T)/6-311+G(2df,p). The computed rotational energy profiles, as well as the calculated values for the geometrical parameters, the vibrational frequencies, and the ionization potential, were in reasonable agreement with previously reported experimental and theoretical results. Except for H3C-CH2 radical, the profiles of chemical potential and hardness along the rotational coordinates present striking contrast to those expected from the corollary of the principle of maximum hardness. Thus, there seems to be no rigorous reason for hardness to be minimum in the transition state region, in general.

Original languageEnglish
Pages (from-to)1343-1353
Number of pages11
JournalJournal of Physical Chemistry A
Volume105
Issue number8
Publication statusPublished - 2001 Mar 1
Externally publishedYes

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hardness
Hardness
profiles
Ionization potential
Chemical potential
Vibrational spectra
ionization potentials
energy
evaluation
methyl radical

ASJC Scopus subject areas

  • Physical and Theoretical Chemistry

Cite this

Internal bond rotation in substituted methyl radicals, H2B-CH2, H3C-CH2, H2N-CH2, and HO-CH2 : Hardness profiles. / Uchimaru, Tadafumi; Chandra, Asit K.; Kawahara, Shun Ichi; Matsumura, Kazunari; Tsuzuki, Seiji; Mikami, Masuhiro.

In: Journal of Physical Chemistry A, Vol. 105, No. 8, 01.03.2001, p. 1343-1353.

Research output: Contribution to journalArticle

Uchimaru, T, Chandra, AK, Kawahara, SI, Matsumura, K, Tsuzuki, S & Mikami, M 2001, 'Internal bond rotation in substituted methyl radicals, H2B-CH2, H3C-CH2, H2N-CH2, and HO-CH2: Hardness profiles', Journal of Physical Chemistry A, vol. 105, no. 8, pp. 1343-1353.
Uchimaru, Tadafumi ; Chandra, Asit K. ; Kawahara, Shun Ichi ; Matsumura, Kazunari ; Tsuzuki, Seiji ; Mikami, Masuhiro. / Internal bond rotation in substituted methyl radicals, H2B-CH2, H3C-CH2, H2N-CH2, and HO-CH2 : Hardness profiles. In: Journal of Physical Chemistry A. 2001 ; Vol. 105, No. 8. pp. 1343-1353.
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abstract = "The energy profiles for the internal bond rotation of substituted methyl radicals, X-CH2 (X = BH2, CH3, NH2, and OH) were examined with B3LYP/6-31G(d) calculations. Energy evaluation of each point along the rotational coordinate was also carried out with single-point calculation at the computational levels of B3LYP/ 6-311+G(2df,p) and QCISD(T)/6-311+G(2df,p). The computed rotational energy profiles, as well as the calculated values for the geometrical parameters, the vibrational frequencies, and the ionization potential, were in reasonable agreement with previously reported experimental and theoretical results. Except for H3C-CH2 radical, the profiles of chemical potential and hardness along the rotational coordinates present striking contrast to those expected from the corollary of the principle of maximum hardness. Thus, there seems to be no rigorous reason for hardness to be minimum in the transition state region, in general.",
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AU - Uchimaru, Tadafumi

AU - Chandra, Asit K.

AU - Kawahara, Shun Ichi

AU - Matsumura, Kazunari

AU - Tsuzuki, Seiji

AU - Mikami, Masuhiro

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AB - The energy profiles for the internal bond rotation of substituted methyl radicals, X-CH2 (X = BH2, CH3, NH2, and OH) were examined with B3LYP/6-31G(d) calculations. Energy evaluation of each point along the rotational coordinate was also carried out with single-point calculation at the computational levels of B3LYP/ 6-311+G(2df,p) and QCISD(T)/6-311+G(2df,p). The computed rotational energy profiles, as well as the calculated values for the geometrical parameters, the vibrational frequencies, and the ionization potential, were in reasonable agreement with previously reported experimental and theoretical results. Except for H3C-CH2 radical, the profiles of chemical potential and hardness along the rotational coordinates present striking contrast to those expected from the corollary of the principle of maximum hardness. Thus, there seems to be no rigorous reason for hardness to be minimum in the transition state region, in general.

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