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Title: Performance of B3PW91, PBE1PBE and OPBE Functionals in Comparison to B3LYP for 13C NMR Chemical Shift Calculations
Authors: Phạm, Vũ Nhật
Nguyen, Thanh Si
Keywords: ¹³C Chemical Shift
Scaling Factor
Issue Date: 2017
Series/Report no.: Journal of Science and Technology Ubon Ratchathani University;.- p.20-30
Abstract: The performance of density functionals B3PW91, PBE1PBE and OPBE are evaluated in comparison to the B3LYP for the ¹³C NMR chemical shift calculations of 20 small molecules. We combine these functionals with several basis sets including 6-311++G(d,p), 6-311++G(2d,2p), 6-311++G(3df,3pd) and cc-PVTZ to analyze the effect on predicting ¹³C NMR chemical shifts. Our computed results show that the use of a simple expression 𝛿𝑠𝑐𝑎𝑙=0.9528𝛿𝑐𝑎𝑙𝑐−0.5986, where 𝛿𝑐𝑎𝑙𝑐 and 𝛿𝑠𝑐𝑎𝑙 are the calculated and the linearly scaled values of the ¹³C chemical shifts, respectively, significantly improves the mean absolute deviations for a set of 75 chemical shifts considered. In addition the B3PW91 is superior to the other three density functionals and the GIAO B3PW91/6-311++G(2d,2p) is sufficient to determine accurate ¹³C chemical shifts. The ¹³C NMR chemical shifts of a larger system, i.e. Taxol molecule, are also computed and compared with experimental values.
Appears in Collections:Tạp chí quốc tế

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