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Four‐Component Relativistic DFT Calculations of 13 C Chemical Shifts of Halogenated Natural Substances
Author(s) -
Casella Girolamo,
Bagno Alessandro,
Komorovsky Stanislav,
Repisky Michal,
Saielli Giacomo
Publication year - 2015
Publication title -
chemistry – a european journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.687
H-Index - 242
eISSN - 1521-3765
pISSN - 0947-6539
DOI - 10.1002/chem.201502252
Subject(s) - component (thermodynamics) , chemistry , natural (archaeology) , computational chemistry , physics , thermodynamics , archaeology , history
We have calculated the 13 C NMR chemical shifts of a large ensemble of halogenated organic molecules (81 molecules for a total of 250 experimental 13 C NMR data at four different levels of theory), ranging from small rigid organic compounds, used to benchmark the performance of various levels of theory, to natural substances of marine origin with conformational degrees of freedom. Carbon atoms bonded to heavy halogen atoms, particularly bromine and iodine, are known to be rather challenging when it comes to the prediction of their chemical shifts by quantum methods, due to relativistic effects. In this paper, we have applied the state‐of‐the‐art four‐component relativistic density functional theory for the prediction of such NMR properties and compared the performance with two‐component and nonrelativistic methods. Our results highlight the necessity to include relativistic corrections within a four‐component description for the most accurate prediction of the NMR properties of halogenated organic substances.