- Tytuł:
-
Benzen i metan jako wzorce przesunięcia chemicznego 1 H I 13 C NMR w obliczeniach teoretycznych
Benzene and methane as a and 13 H I 13 C NMR chemical shift references in theoretical calculations - Autorzy:
-
Rzepiela, Kacper
Gajda, Tomasz
Buczek, Aneta
Broda, Małgorzta A.
Kupka, Teobalt - Powiązania:
- https://bibliotekanauki.pl/articles/172062.pdf
- Data publikacji:
- 2020
- Wydawca:
- Polskie Towarzystwo Chemiczne
- Tematy:
-
tensor ekranowania magnetycznego
wzorce przesunięcia chemicznego
benzen
metan
cytozyna
izopren
nuclear magnetic shielding tensor
chemical shift references
benzene
methane
cytosine
isoprene - Opis:
- NMR spectroscopy belongs to the most versatile techniques used in chemical laboratory for testing the presence of various compounds and elucidation of their structure. In case of more complex natural products chemical intuition and experience applied to analysis of experimental spectra is often supported by theoretical modeling of NMR spectra. However, theoretical predictions should be reliable and the errors associated with the approximations inherent to the existing methods minimized. In this respect, systematic errors, present in calculation of isotropic nuclear magnetic shieldings of the studied molecule need to be minimized. Conversion of nuclear shieldings of the studied molecule to the corresponding chemical shifts is performed by using a calculated reference molecule. This way systematic errors partly cancel and the remaining inaccuracies are efficiently decreased by using a properly selected theoretical reference molecule. In this work we demonstrate the impact of calculation method (selected density functional) and basis set on the predicted isotropic nuclear magnetic shieldings of free benzene and methane in vacuum and in popular solvents using a simple PCM approach. We propose the use of B3LYP, OPBE density functionals and recently designed xOPBE one in combination with Pople’s and Dunning’s basis sets, as well as with the modified STO-3G one. The new, STO(1M)-3G basis set was designed by Leszczyński and co-workers for efficient prediction of 13C NMR parameters in large organic molecules. Two molecules were selected to demonstrate the performance of GIAO B3LYP, OPBE and xOPBE for prediction of 1H and 13C NMR chemical shifts in vacuum and solution in comparison with available experimental data.
- Źródło:
-
Wiadomości Chemiczne; 2020, 74, 9-10; 609-627
0043-5104
2300-0295 - Pojawia się w:
- Wiadomości Chemiczne
- Dostawca treści:
- Biblioteka Nauki
Artykuł