ISSN:
0030-4921
Keywords:
Chemistry
;
Analytical Chemistry and Spectroscopy
Source:
Wiley InterScience Backfile Collection 1832-2000
Topics:
Chemistry and Pharmacology
Notes:
C-13 and F-19 NMR spectra of seventeen para-substituted fluorobenzenes were measured and the chemical shifts as well as coupling constants with respect to substituents were analysed. The chemical shifts of the fluorine, the C1 and the C2 atoms were found to depend on the total electron densities. In the case of the C3 atom, the chemical shifts seem to depend on π-electron densities rather than the total electron densities. The present calculations also indicate that the chemical shift of the C4 atom depends mainly on σ-electron densities due to the inductive effects of substituents. The strongest factor influencing the coupling constant, nJ(C—F), is also considered to be the π-electron densities on the carbon atoms. In the case of the direct couplings, 1J(C—F), the π-bond orders are important.
Additional Material:
4 Ill.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1002/mrc.1270040605
Permalink
