SO Effects on Nuclear Shieldings of Neighbor Atoms

We will now attempt to extract qualitative models for the chemical interpretation of NMR chemical shifts from the admittedly sometimes quite complicated theoretical formalisms outlined above. And we will provide examples of explicit quantum chemical calculations that corroborate the proposed models. The most widely studied field, in which much insight has been obtained recently, are SO effects of atoms neighboring some heavy-atom SO center . A significantly revised view of heavy -atom effects on chemical shifts has arisen from the theoretical studies. 

The reduced coupling constants follow the expected damped 

For example, the observation of hormal or inverse halogen dependence (NHD vs IHD [78]) of NMR chemical shifts throughout the periodic table may be understood to a large extent from this rule. Halogen-substituted main group compounds experience particularly large SO effects, provided that the NMR atom is in its maximum formal oxidation state (e.g. B , Al , Ga , In, Tl , 

SO corrections were computed within the atomic meanfield approximation, using the approach in [68,69] (other parameters as in [79]). 

PBr2l2 [81b], An enormous of ca.-8000 ppm on the Pb shift in the unknown Pbl4 has been predicted by ZORA-DFT calculations [80]. 

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