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4279108 
Journal Article 
Theoretical Study on C-13 Nuclear Magnetic Resonance Spectra of Several Coumarin Derivatives 
Jia Fei-yun; Su Feng-fa; Ran Ming; Zhang Bo 
2018 
Yes 
Guangpuxue yu Guangpu Fenxi / Spectroscopy and Spectral Analysis
ISSN: 1000-0593 
38 
1 
320-325 
WOS:000423649200058 
The structure of the six kinds of coumarin derivatives has been optimized at the level of B3LYP/6-311G (d, p), under which the stability has been verified by means of Vibration analysis. Moreover, NMR Spectra of the coumarin derivatives compounds have been studied at the level of B3LYP/6-311G (d, p) by GI-AO method. The results showed that the structure of the six compounds, a larger conjugated system, had good planarity. Different Substituents and different positions of substituents all have different influences on NMR of the several coumarin derivatives. In general, after the hydrogen atom on the benzene ring is substituted by other groups, the delta value of the alpha-C atom next to the substituent changes obviously, the delta value of the Ortho carbon atoms have great change too, but the delta value of the meta carbon atom have almost no change. The effect of electronegativity of substituents on alpha-C atoms presents obvious regularity, while the influence of conjugate effect on carbon atoms of benzene ring is more complex. Finally, in order to show the correlation between theoretical calculation and experimental values, we showed the correlation diagram of the chemical shift values of the six kinds of derivatives, and carried on the linear regression. Results showed that the correlation between the chemical shift theory and the experimental value of the six kinds of the Coumarin derivatives was very good. 
NMR; Theoretical study; Coumarin derivatives; Chemical shift