A multi-standard approach for GIAO (13)C NMR calculations.
The influence of the reference standard employed in the calculation of (13)C NMR chemical shifts was investigated over a large variety of known organic compounds, using different quantum chemistry methods and basis sets. After detailed analysis of the collected data, we found that methanol and benzene are excellent reference standards for computing NMR shifts of sp(3)- and sp-sp(2)-hybridized carbon atoms, respectively. This multi-standard approach (MSTD) performs better than TMS in terms of accuracy and precision and also displays much lower dependence on the level of theory employed. The use of mPW1PW91/6-31G(d)//mPW1PW91/6-31G(d) level is recommended for accurate (13)C NMR chemical shift prediction at low computational cost.
Sarotti
Ariel M
AM
Instituto de Química Rosario (CONICET), Facultad de Ciencias Bioquímicas y Farmacéuticas, Universidad Nacional de Rosario, Suipacha 531, Rosario (2000), Argentina. sarotti@iquir-conicet.gov.ar
Pellegrinet
Silvina C
SC
D002247:Carbon Isotopes; D003198:Computer Simulation; D009682:Magnetic Resonance Spectroscopy / Q000592:standards*; D015394:Molecular Structure; D009930:Organic Chemicals / Q000737:chemistry*; D011789:Quantum Theory; D012015:Reference Standards
D002247:Carbon Isotopes; D009930:Organic Chemicals