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A simple, self‐consistent electrostatic model for quantitative prediction of the activation energies of four‐center reactions. II. *
Author(s) -
Haugen G. R.,
Benson S. W.
Publication year - 1970
Publication title -
international journal of chemical kinetics
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.341
H-Index - 68
eISSN - 1097-4601
pISSN - 0538-8066
DOI - 10.1002/kin.550020308
Subject(s) - chemistry , polarizability , mole , hydrogen bond , molecule , hydrogen atom , dipole , atom (system on chip) , crystallography , computational chemistry , group (periodic table) , organic chemistry , computer science , embedded system
A simple electrostatic model of point dipoles is used which permits direct calculation of the activation energies for the addition of the molecules H 2 O, H 2 S, H 3 N, and H 3 P to olefins. These calculated values agree with the known experimental data to within ±2 kcal/mole on the average. It was found that the best fit could be obtained with a polar transition state that corresponded to a reduction in bond order from 1 to ½ for the bond‐breaking coordinates and an increase in bond order from 0 to 0.18 for the bond‐forming coordinates. The replacement of a hydrogen atom of the species H 2 O, H 2 S, H 3 N, or H 3 P by a polarizable methyl group is expected to stabilize the charge on the central atoms. The following stabilization energies for the pairs H 2 OCH 3 OH, H 2 SCH 3 SH, H 3 NCH 3 NH 2 , H 3 PCH 3 PH 2 were calculated: −4.8 kcal/mole, −0.7 kcal/mole, −1.9 kcal/mole, −0.8 kcal/mole, respectively.