Carbon-13 Nuclear Magnetic Resonance Spectroscopy. V. Studies on Carbon-13 Magnetic Resonance Spectra in Aromatic and Heteroaromatic Systems. (1). Mono- and Disubstituted Benzene Derivatives

Abstract

Numerous carbon-13 chemical shifts of monosubstituted, meta- and para-disubstituted benzene derivatives as well as symmetrically and unsymmetrically substituted toluene and chlorobenzene homologs were measured to test the reliability of the simple sum rule from monosubstituted benzene derivatives. The chemical shifts of meta- and para-disubstituted benzene derivatives were examined with respect to the substituent constants σi and σπ.