Long-range relativistic heavy atom effect on H-1 NMR chemical shifts of selenium- and tellurium-containing compounds

摘要

Previously unknown manifestation of heavy atom effect on the NMR chemical shifts of beta- and gamma-protons initiated by the relativistic effects of the tellurium and selenium atoms has been investigated in the representative series of selenium- and tellurium-containing compounds. To approve the four-component density functional approach to be the appropriate tool for the investigation of the heavy atom on light atom effect (HALA), the benchmark calculations of the proton chemical shifts have been performed at the CCSD level using comprehensively chosen locally dense basis set with taking into account solvent, vibrational, and relativistic corrections. A good agreement with the experimental data was achieved. The magnitudes of the relativistic HALA corrections to beta- and gamma-proton chemical shifts were found to vary in a wide range, namely from -3.08 ppm for the gamma-proton of methyltelluraldehyde to 14.51 ppm for beta-proton in benzotelluraldehyde.