A GIPAW versus GIAO-ZORA-SO study of 13C and 15N CPMAS NMR chemical shifts of aromatic and heterocyclic bromo derivatives

Theoretical simulation of NMR parameters in compounds bearing heavy atoms generally requires the application of relativistic corrections. We report herein the theoretical characterization of C-13 and N-15 CPMAS NMR of known bromo-derivative crystals by using both the GIPAW and the combined GIAO-ZORA-SO approximation methods. Several statistical analyses were performed to compare both approaches, with non-relativistic GIPAW method being more useful to predict the C-13 and N-15 chemical shifts. The problem of applying GIPAW to crystal structures showing static or dynamic crystalline disorder of the special class resulting in half-protons will be discussed in detail.