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Relationships between electronic substituent parameters
Author(s) -
Sæthre Leif J.,
Thomas T. Darrah
Publication year - 1991
Publication title -
journal of physical organic chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.325
H-Index - 66
eISSN - 1099-1395
pISSN - 0894-3230
DOI - 10.1002/poc.610041007
Subject(s) - substituent , chemistry , polarizability , delocalized electron , electron delocalization , parameterized complexity , computational chemistry , electronic effect , series (stratigraphy) , state (computer science) , electronic structure , stereochemistry , organic chemistry , molecule , steric effects , mathematics , algorithm , paleontology , biology
Core‐electron energies for sulphur in a series of 2‐substituted thiophenes have been used to investigate the relationship between electronic substituent parameters as developed by Taft and Topsom and by Charton. Initial‐ and final‐state energies are analysed in terms of familiar substituent effects, such as field, delocalization and polarizability. The results show that the data correlate equally well with both sets of parameters and that there are many common features between the two methods. Both agree that resonance delocalization contributes significantly to the initial state, but has virtually no effect on the final state. In connection with this investigation we have also correlated the parameters for 31 substituents that are parameterized in the two approaches. The results of this more general study indicate some real differences between these and suggest that neither of the parameterizations incorporates all the electronic effects.