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Comparison of different theory models and basis sets in the calculation of 13 C NMR chemical shifts of natural products
Author(s) -
Cimino Paola,
GomezPaloma Luigi,
Duca Dario,
Riccio Raffaele,
Bifulco Giuseppe
Publication year - 2004
Publication title -
magnetic resonance in chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.483
H-Index - 72
eISSN - 1097-458X
pISSN - 0749-1581
DOI - 10.1002/mrc.1410
Subject(s) - chemistry , basis (linear algebra) , chemical shift , computational chemistry , carbon 13 nmr , organic chemistry , geometry , mathematics
Abstract The influence of the calculation method in mimicking experimental 13 C NMR chemical shifts of 15 low‐polarity natural products singularly containing 10–20 carbon atoms was investigated by employing different quantum chemistry approaches and basis sets, both in the preliminary geometry optimizations and in the following single‐point 13 C GIAO calculations of the NMR chemical shifts. The geometries of the involved species were optimized at the PM3, HF, B3LYP and mPW1PW91 levels whereas the 13 C NMR parameters were determined at the HF, B3LYP and mPW1PW91 levels. Different combinations of basis sets were also tested. The consistency and efficiency of the considered combinations of geometry optimizations and GIAO 13 C NMR calculations were thoroughly checked by the analysis of statistical parameters concerning computed and experimental 13 C NMR chemical shift values. Copyright © 2004 John Wiley & Sons, Ltd.