ISSN:
1434-193X
Keywords:
Resonance
;
Hindered resonance
;
Steric hindrance
;
Conformation analysis
;
Chemistry
;
General Chemistry
Source:
Wiley InterScience Backfile Collection 1832-2000
Topics:
Chemistry and Pharmacology
Notes:
Substituent effects of the tert-butyl group in isomeric tert-butylbenzoic acids have been investigated on the basis of enthalpies of formation, gas-phase acidities, acidities in methanol and in dimethyl sulfoxide, and the IR spectra in tetrachloromethane. In contrast to 2-methylbenzoic acid, 2-tert-butylbenzoic acid must adopt a non-planar conformation, as is confirmed by its IR spectrum. Enhanced acidity in the gas phase has been found for all isomers and attributed to a pole-induced dipole interaction in the anion (polarizability effect); in the ortho isomer the steric inhibition of resonance is only responsible for a minor part of the observed effect. In solution, the electrostatic interaction is attenuated, but remains strong in the case of the ortho isomer.
Additional Material:
5 Ill.
Type of Medium:
Electronic Resource
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