Ab initio MO study of benzylic cations. Part 3. Protonated benzoyl derivatives

Nakata, Kohei; Fujio, Mizue; Mishima, Masaaki; Tsuno, Yuho; Nishimoto, Kichisuke

doi:10.1002/(sici)1099-1395(199812)11:12<857::aid-poc81>3.0.co;2-1

Cited by 10 publications

(2 citation statements)

References 40 publications

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“…This implies that the resultant ρ and resonance demand ( r + ) values are sufficiently accurate to provide quantitative informations with respect to the natures of ionic species or transition states. It was theoretically confirmed that the characteristic r + value indicates the degree of resonance interaction between the cationic center and the aromatic moiety in a given system . In addition, Eqn itself has been found to be reproduced theoretically .…”

Section: Introductionmentioning

confidence: 61%

Theoretical study of substituent effects on the gas‐phase stabilities of phenoxide anions

Nakata

Fujio

Nishimoto

et al. 2012

J of Physical Organic Chem

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Relative gas-phase stabilities of 25 kinds of ring-substituted phenoxide anions were determined theoretically using proton transfer reactions. The energies and geometries of phenoxide anions and their corresponding phenols, which are involved in the reactions, were calculated at the B3LYP/6-311+G(2d,p) level of theory. The comparison of the obtained substituent effects with those of benzylic anions revealed that the stabilities of phenoxide anions were governed by the inductive effect and two additive effects of ring substituents in a manner similar to that of benzylic anions. Statistical analyses elucidated that the behavior of the substituent effects of phenoxide anions as well as benzylic anions can be described quantitatively by three terms using an extended Yukawa-Tsuno equation:. Through examinations of the structural changes and charge distributions in the anions, these additional effects were identified as the resonance and saturation effects, which stabilize anions by the para + R groups and the electron-releasing groups, respectively. a-Substituents of benzylic anions. d Ring substituents included in the analyses. The 'meta' substituents consist of meta EWGs of m-NO 2 , m-CN, m-CHO, m-CF 3 , m-COMe, m-Cl, m-F, and H. e Correlation coefficients. f Residual standard deviations. g Numbers of substituents included in the analyses. h Cyclopentadienyl K. NAKATA ET AL. wileyonlinelibrary.com/journal/poc

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Section: Introductionmentioning

confidence: 61%

Theoretical study of substituent effects on the gas‐phase stabilities of phenoxide anions

Nakata

Fujio

Nishimoto

et al. 2012

J of Physical Organic Chem

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“…Eqn was applied to an enormous number of cationic systems, where resultant ρ and r + values were sufficiently accurate to provide quantitative information regarding the natures of cationic species. It has been confirmed that the characteristic “resonance demand” parameter ( r + value) indicates the degree of through‐resonance in a given system . In addition, Eqn itself has been reproduced by computational methods .…”

Section: Introductionmentioning

confidence: 65%

Computational study of substituent effects on the gas‐phase stabilities of N‐phenylguanidinium ions

Nakata

Siehl

Maas

et al. 2016

J of Physical Organic Chem

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Relative gas-phase stabilities of ring-substituted N-phenylguanidinium ions were determined at the B3LYP/6-311+G(2d,p) level of theory, and the substituent effects were analyzed by the Yukawa-Tsuno equation. The total stabilization energies (TSEs) of the ring-substituted cations were determined by the chloride-transfer reaction. The substituent-effect analysis showed a considerable amount of contamination from the chloride salts in the TSEs. The cation stabilization energies (CSEs) were then determined by an isodesmic reaction where the neutral species are substituted benzenes. The substituent-effect analysis gave r + = À0.04, which indicates a very small through-resonance. The dihedral angle φ between the guanidinium and benzene ring moieties was found to be orthogonal in the fully optimized cation. The r + value decreased with the decrease in φ, to give r + = À0.15 in the planar cation. The degree of the through-resonance decreased as the cation approached the planar structure. A detailed investigation with NBO analyses indicated through-resonance mechanisms concerned by the π-σ* interaction between the benzene π-electron system and the adjacent bonds as well as the direct interaction between the benzene π-electron system and the distant p-orbital at the β-position. The former becomes dominant as the structure of the cation approaches an orthogonal conformation (φ = 90°), while the latter becomes dominant as the structure approaches the planar conformation (φ = 0°). The r + value changed with the dihedral angle φ, reflecting the sum of these interactions. The mechanisms of stabilization and delocalization caused by the substituents attached to the guanidinium ion unit are discussed.

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Theoretical Study of Substituent Effects on the Gas‐Phase Acidities of Benzoic and Phenylacetic Acids

Nakata¹,

Fujio²,

Nishimoto³

et al. 2013

ChemPlusChem

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The relative gas‐phase acidities of 25 ring‐substituted benzoic and phenylacetic acids were theoretically determined with proton‐transfer reactions. The energies and geometries of the acids and their corresponding anions, which were involved in the reactions, were calculated at the B3LYP/6‐311+G(2d,p) level of theory. The obtained substituent effects were compared with each other and those of phenols. The acidities of the benzoic and phenylacetic acids were governed by three kinds of electronic effects (inductive, resonance, and saturation effects), which confirmed that the acidities were reflected in the nature of the benzoate and phenylacetate anions, respectively. Substituent effect analyses with an extended Yukawa–Tsuno equation, ${ - {\rm{\Delta }}E_X = \rho \left( {\sigma ^0 + r^ - {\rm{\Delta }}\bar \sigma _{\rm{R}}^ - + s{\rm{\Delta }}\bar \sigma _{\rm{S}} } \right)}$, gave excellent linear correlations for both anionic systems. The degrees of through‐resonance and saturation effects in the phenylacetate anion, as reflected by the resultant r− and s values, were unexpectedly larger than those in the benzoate anion, which were mainly attributed to hyperconjugation and through‐space interactions between the anionic moiety and the benzene π‐electron system, respectively. The acidities of the benzoic acids (or stabilities of the benzoate anions) constituted a better system than the acidities of phenylacetic acids (or stabilities of the phenylacetate anions) for a standard of the normal substituent constants (σ0) for anions in the gas phase, in contrast to solution‐phase results.

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Ab initio MO study of benzylic cations. Part 3. Protonated benzoyl derivatives

Cited by 10 publications

References 40 publications

Theoretical study of substituent effects on the gas‐phase stabilities of phenoxide anions

Theoretical study of substituent effects on the gas‐phase stabilities of phenoxide anions

Computational study of substituent effects on the gas‐phase stabilities of N‐phenylguanidinium ions

Theoretical Study of Substituent Effects on the Gas‐Phase Acidities of Benzoic and Phenylacetic Acids

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