Nuclear charge distribution effects on NMR J-couplings

What is it about?

The calculation of NMR J-couplings is so accurate now that one may want to know how large are the effects of nuclear charge distribution on nuclei. Both spectroscopic molecular properties, i.e. J-couplings and magnetic shieldings are local, meaning that they depend on the electronic distribution on the nuclear site. Then, relativistic effects are important and also the nuclear charge distribution. The effect is larger than 10 % in heavy atoms when relativity is included.

Featured Image

Why is it important?

This is a systematic analysis of nuclear charge distribution, NChD, effects on NMR spectroscopic parameters. The effect of the distribution of dipole moments within the nuclei is not included. The effect of NChD is quite important so that it should be included when one wants to get reliable results. We show how large are they and how to include them in calculations. We also show for the first time the effect of considering NChD effects of vicinal nuclei on shielded nuclei or J-coupled.