A G2(+) level investigation of the gas-phase non-identity S<sub>N</sub>2 reactions of halides with halodimethylamine

Ren, Yi; Zhu, Hua‐Jie

doi:10.1016/j.jasms.2003.11.017

Cited by 27 publications

(49 citation statements)

References 25 publications

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“…[16,[19][20][21][22][23][24][25] Therefore, the G2(+) theory was also used in the present study. The Gaussian 98 program packages [26] with standard Pople-type basis sets were used in all calculations.…”

Section: Methodsmentioning

confidence: 99%

G2(+) Investigation on the α‐Effect in the S_N2 Reactions at Saturated Carbon

Ren

Yamataka

2006

Chemistry A European J

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As a continuing theoretical study on the alpha-effect in the S(N)2 reactions at saturated carbon centers, 28 gas-phase reactions have been examined computationally by using the high-level G2(+) method. The reactions include: Nu(-)+CH(3)X-->CH(3)Nu+X(-) (X=F and Cl; Nu(-)=HO(-), HS(-), CH(3)O(-), Cl(-), Br(-), HOO(-), HSO(-), FO(-), ClO(-), BrO(-), NH(2)O(-), and HC(==O)OO(-)). It was found that all alpha-nucleophiles examined exhibit downward deviations from the correlation line between the overall barriers and proton affinities for normal nucleophiles, indicating the existence of the alpha-effect in the gas phase. The transition states (TS) for the alpha-nucleophiles are characterized by less advanced C--X bond cleavages than the normal nucleophiles, leading to smaller deformation energies and overall barriers. The size of the alpha-effect is related to the electron density on the alpha-atom, and increases when the position of alpha-atom is changed from left to right and from bottom to top in the periodic table. The reaction with CH(3)F exhibits a larger alpha-effect than that with CH(3)Cl, which can be explained by a later TS and a more positively charged methyl group at the TS for CH(3)F, [NuCH(3)F](- not equal). Thus, a higher electron density on the alpha-atom and a more positive methyl moiety at the TS result in a larger alpha-effect.

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Section: Methodsmentioning

confidence: 99%

G2(+) Investigation on the α‐Effect in the S_N2 Reactions at Saturated Carbon

Ren

Yamataka

2006

Chemistry A European J

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“…Their prediction was validated by the selected ion flow tube experiments on the gas phase S N 2@N reactions of NH 2 Cl with HO − , RO − (R = Me, Et, Pr, PhCH 2 , CF 3 CH 2 ), F − , HS − , and Cl − . Some identity and nonidentity S N 2@N reactions were studied by Ren et al, and two possible mechanisms, the inversion and the configuration retention, were compared, indicating that the activation barrier is basically controlled by the GB value of the nucleophile, and the retention pathway is energetically unfavorable. More recently, Feng and coworkers performed ab initio molecular dynamics simulations on the S N 2@N reactions of OH − with NH 2 F and NH 2 Cl .…”

Section: Introductionmentioning

confidence: 97%

The α-effect exhibited in gas-phase S_N2@N and S_N2@C reactions

et al. 2013

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In order to explore the existence of α-effect in gas-phase S(N)2@N reactions, and to compare its similarity and difference with its counterpart in S(N)2@C reactions, we have carried out a theoretical study on the reactivity of six α-oxy-Nus (FO(-), ClO(-), BrO(-), HOO(-), HSO(-), H2NO(-)) in the S(N)2 reactions toward NR2Cl (R = H, Me) and RCl (R = Me, i-Pr) using the G2(+)M theory. An enhanced reactivity induced by the α-atom is found in all examined systems. The magnitude of the α-effect in the reactions of NR2Cl (R = H, Me) is generally smaller than that in the corresponding S(N)2 reaction, but their variation trend with the identity of α-atom is very similar. The origin of the α-effect of the S(N)2@N reactions is discussed in terms of activation strain analysis and thermodynamic analysis, indicating that the α-effect in the S(N)2@N reactions largely arises from transition state stabilization, and the "hyper-reactivity" of these α-Nus is also accompanied by an enhanced thermodynamic stability of products from the n(N) → σ*(O-Y) negative hyperconjugation. Meanwhile, it is found that the reactivity of oxy-Nus in the S(N)2 reactions toward NMe2Cl is lower than toward i-PrCl, which is different from previous experiments, that is, the S(N)2 reactions of NH2Cl is more facile than MeCl.

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“…[1–3] The S N 2 reactions at nitrogen (N) center play significant roles in both organic synthesis and carcinogenesis, and therefore, they have attracted much attention of researchers. [4–24]…”

Section: Introductionmentioning

confidence: 99%

“…Subsequently, Yang et al[15] studied the potential energy profiles for the gas‐phase nonidentity S N 2 reactions at N center at the MPW1K/6‐31+G(d,p) level, and the correlations of the central barriers and overall barriers with the reaction exothermicity were revealed. Furthermore, the relationship between the periodic table and the intrinsic barrier,[16] the ion pairs as nucleophiles,[17, 18] the methyl substitution,[19] the electron transfer,[20, 21] the intramolecular nucleophilic substitution,[22] and the solvent effects[23, 24] for the S N 2 reactions at N center were also deeply investigated.…”

Section: Introductionmentioning

confidence: 99%

Assessment of ab initio MP2 and density functionals for characterizing the potential energy profiles of the S_N2 reactions at N center

Yu¹

2012

J Comput Chem

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The potential energy profiles of five selected bimolecular nucleophilic substitution (S(N) 2) reactions at nitrogen (N) center have been reinvestigated with the CCSD(T), G3[MP2,CCSD(T)], MP2, and some density functional methods. The basis sets of 6-31+G(d,p) and 6-311+G(3d,2p) are used for the MP2 and density functional calculations. Taking the relative energies at the CCSD(T)/CBS level of theory as benchmarks, we recommend the MP2, B97-K, B2K-PLYP, BMK, ωB97X-D, M06-2X, M05-2X, CAM-B3LYP, M08-SO, and ωB97X methods to generally characterize the potential energy profiles for the S(N)2 reactions at N center. Furthermore, these recommended methods with the relatively small 6-31+G(d,p) basis set may also be used to perform direct classical trajectory simulations to uncover the dynamic behaviors of the S(N)2 reactions at N center.

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A G2(+) level investigation of the gas-phase non-identity S_N2 reactions of halides with halodimethylamine

Cited by 27 publications

References 25 publications

G2(+) Investigation on the α‐Effect in the S_N2 Reactions at Saturated Carbon

G2(+) Investigation on the α‐Effect in the S_N2 Reactions at Saturated Carbon

The α-effect exhibited in gas-phase S_N2@N and S_N2@C reactions

Assessment of ab initio MP2 and density functionals for characterizing the potential energy profiles of the S_N2 reactions at N center

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A G2(+) level investigation of the gas-phase non-identity SN2 reactions of halides with halodimethylamine

Cited by 27 publications

References 25 publications

G2(+) Investigation on the α‐Effect in the SN2 Reactions at Saturated Carbon

G2(+) Investigation on the α‐Effect in the SN2 Reactions at Saturated Carbon

The α-effect exhibited in gas-phase SN2@N and SN2@C reactions

Assessment of ab initio MP2 and density functionals for characterizing the potential energy profiles of the SN2 reactions at N center

Contact Info

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Resources

About

A G2(+) level investigation of the gas-phase non-identity S_N2 reactions of halides with halodimethylamine

G2(+) Investigation on the α‐Effect in the S_N2 Reactions at Saturated Carbon

G2(+) Investigation on the α‐Effect in the S_N2 Reactions at Saturated Carbon

The α-effect exhibited in gas-phase S_N2@N and S_N2@C reactions

Assessment of ab initio MP2 and density functionals for characterizing the potential energy profiles of the S_N2 reactions at N center