Intrinsic Long Range Deuterium Isotope Effects on 13C NMR Chemical Shifts as a Conformational Probe of Benzene Derivatives
نویسندگان
چکیده
13C NMR spectra of molecules containing one or two benzene rings linked with CH=CH2, CH=CH (transor cis-), C C and CH=N groups revealed the existence of long range deuterium isotope effects on 13C chemical shifts. It was found that deuterium isotope effects over six bonds (6D) are related to the conformation of investigated molecules. Molecular torsional angles were calculated by ab initio HF/6–31G* and AM1 semi-empirical calculations. Very good linear correlations were established between experimentally observed 6 and theoretical torsional angles obtained from ab initio and semi-empirical calculations.
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