Theoretical studies on the gas-phase nucleophilic substitution reactions of benzyl chlorides with phenoxides and thiophenoxides

1998 ◽  
Vol 11 (2) ◽  
pp. 115-124 ◽  
Author(s):  
Wang Ki Kim ◽  
Wang Sun Ryu ◽  
In-Suk Han ◽  
Chang Kon Kim ◽  
Ikchoon Lee
Keyword(s):  
Nucleophilic Substitution ◽  
Gas Phase ◽  
Theoretical Studies ◽  
Substitution Reactions ◽  
Nucleophilic Substitution Reactions ◽  
Benzyl Chlorides

STUDIES ON NUCLEOPHILIC SUBSTITUTION REACTIONS AT CARBON (SN2(C)) AND SILICON (SN2(Si)) IN TERMS OF AB INITIO, POTENTIAL, ACTING ON AN ELECTRON IN A MOLECULE AND MOLECULAR FACE THEORY

2009 ◽  
Vol 08 (supp01) ◽  
pp. 983-1001 ◽  
Author(s):  
YAN-LI DING ◽  
LI-DONG GONG ◽  
DONG-XIA ZHAO ◽  
MING-BO ZHANG ◽  
ZHONG-ZHI YANG
Keyword(s):  
Ab Initio ◽  
Nucleophilic Substitution ◽  
Gas Phase ◽  
Chemical Bond ◽  
Energy Transition ◽  
High Energy ◽  
Ab Initio Method ◽  
Substitution Reactions ◽  
Nucleophilic Substitution Reactions ◽  
High Energy Transition

The gas-phase identity bimolecular nucleophilic substitution reactions, Cl- + CH3 Cl → ClCH3 + Cl- and Cl- + SiH3Cl → ClSiH3 + Cl- , are investigated in terms of the ab initio method, potential acting on an electron in a molecule (PAEM) and molecular face (MF) theory. The computations have been performed at the CCSD(T)/aug-cc-pVTZ//MP2/6-311+G(3df,3pd) and CISD/aug-cc-pVDZ level. Based on the ab initio calculation, according to the PAEM theory, the strength of a chemical bond during forming or rupturing may be characterized by the D pb , which is a new physical quantity relating to the barrier height of the PAEM along a chemical bond. According to the MF theory, the interesting pictures of electron transfer and interpolarization effect between the reactants are clearly demonstrated to provide visualized spatial changing features of the MF for the title reactions along the IRC routes. The reason why [ Cl⋯CH3⋯Cl]- is a high-energy transition state is also analyzed in comparison with the stable low-energy intermediate [ Cl⋯SiH3⋯Cl]- .

Isotope effects in nucleophilic substitution reactions. IV. The effect of changing a substituent at the α carbon on the structure of SN2 transition states

1982 ◽  
Vol 60 (19) ◽  
pp. 2500-2520 ◽  
Author(s):  
Kenneth Charles Westaway ◽  
Zbigniew Waszczylo
Keyword(s):  
Nucleophilic Substitution ◽  
Isotope Effects ◽  
Transition States ◽  
Activation Parameters ◽  
Kinetic Studies ◽  
Kinetic Isotope Effects ◽  
Substitution Reactions ◽  
Nucleophilic Substitution Reactions ◽  
Kinetic Isotope ◽  
Benzyl Chlorides

Kinetic studies, secondary α-deuterium kinetic isotope effects, primary chlorine kinetic isotope effects (1), Hammett ρ values determined by changing the substituent in the nucleophile, and activation parameters have been used to determine the detailed (relative) structures of the transition states for the SN2 reactions between para-substituted benzyl chlorides and thiophenoxide ion. A rationale for the U-shaped Hammett ρ plots observed when para-substituted benzyl compounds react with negatively charged nucleophiles is also presented.

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