ISSN:
0030-4921
Keywords:
Chemistry
;
Analytical Chemistry and Spectroscopy
Source:
Wiley InterScience Backfile Collection 1832-2000
Topics:
Chemistry and Pharmacology
Notes:
A series of para- and meta-substituted acetophenones were prepared which were highly labeled with 18O at the carbonyl function. The natural abundance 13C NMR spectra of the compounds were recorded and the 18O-isotope-induced shifts of the carbonyl carbon were measured in order to determine possible substituent group electronic effects on the 18O-isotope shift. The isotope shifts were found to be correlated with a number of properties which demonstrate the molecular basis of the isotope shift. Good correlations were obtained for the isotope shift as a function of σp+, the carbonyl stretching frequency, the carbonyl group bond order, the n→π**transition of the carbonyl group and the chemical shift of the ipso carbon. In contrast, no correlation was observed between the magnitude of the 18O-induced isotope shift and the 13C chemical shift of the carbonyl carbon. These properties are discussed in connection with the theoretical basis of the isotope shift.
Additional Material:
1 Ill.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1002/omr.1270210108
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