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Effects of neutral and charged substituents on the infrared carbonyl stretching frequencies in phenyl and alkyl benzoates in DMSO.
- Source :
- Journal of Physical Organic Chemistry; Mar2017, Vol. 30 Issue 3, pn/a-N.PAG, 8p
- Publication Year :
- 2017
-
Abstract
- The carbonyl infrared stretching frequencies for 57 meta-, para- and ortho-substituted phenyl benzoates, C<subscript>6</subscript>H<subscript>5</subscript>CO<subscript>2</subscript>C<subscript>6</subscript>H<subscript>4</subscript>-X and alkylbenzoates, C<subscript>6</subscript>H<subscript>5</subscript>CO<subscript>2</subscript>R, containing besides neutral substituents the charged substituents in phenoxy and alkoxy part in dimethyl sulfoxide (DMSO) have been recorded. The carbonyl stretching frequencies, ν<subscript>CO</subscript>, for meta- and para-substituted phenyl esters of benzoic acids in the case of neutral substituents were found to correlate well with the substituent constants, σ°. The ν<subscript>CO</subscript> values for ortho derivatives correlated with the inductive substituent constants, σ<subscript>I</subscript>, only. The values of constants for charged substituents, σ°<subscript>±</subscript>, calculated on the basis of the ν<subscript>CO</subscript> and the <superscript>13</superscript>C NMR chemical shifts, δ<subscript>CO</subscript>, in DMSO agree well with the σ°<subscript>±</subscript> values for the corresponding ion pairs reported by Hoefnagel and Wepster and those determined from the log k values of the alkaline in 4.4 M NaCl solution at 50 °C. Thus, the values of substituent constants for ion pairs of charged substituents estimated on the basis of aqueous data could be successfully used in non-aqueous solution (DMSO) simultaneously with neutral substituents in case the charged substituents were not completely ionized and are in ion pair form. Copyright © 2016 John Wiley & Sons, Ltd. [ABSTRACT FROM AUTHOR]
Details
- Language :
- English
- ISSN :
- 08943230
- Volume :
- 30
- Issue :
- 3
- Database :
- Complementary Index
- Journal :
- Journal of Physical Organic Chemistry
- Publication Type :
- Academic Journal
- Accession number :
- 121269133
- Full Text :
- https://doi.org/10.1002/poc.3608