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Bulletin of the Korean Chemical Society (BKCS)

ISSN 0253-2964(Print)
ISSN 1229-5949(Online)
Volume 4, Number 1
BKCSDE 4(1)
January 20, 1983 

 
Title
The New Substituent Constants in the Excited States (Ⅱ)
Author
Sang Chul Shim, Joon Won Park, Heui-Suk Ham, Jin-Soon Chung
Keywords
Abstract
In order to standardize the σ*, ρ* is taken as unity for the benzoic acids by analogy with the fact that ρ of benzoic acids in the ground state is taken as unity. The pKa* of many benzoic acid derivatives are determined by UV spectroscopy and fluorescence spectral analysis whenever possible. The σ* constants are derived from the Hammett equation utilizing these pKa* values and the pKa* of the benozic acid derivatives showed better correlationship with σ* than σ, σ+ and σ- as expected. From these σ* values, ρ* of the phenol derivatives was calculated to be 1.28. The new standardized σ* values are calculated from the pKa* values of phenols since more accurate and abundant data are available for phenols than the benzoic acid derivatives.
Page
45 - 47
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