ESTIMATION AND PREDICTION OF
13C NMR CHEMICAL SHIFTS OF CARBON ATOMS IN BOTH ALCOHOLS AND THIOLS
J. Tong, Y. Chen, S. Liu, X. Xu, F. Cheng
Shaanxi University of Science and Technology, PR China
Jianbotong@yahoo.com.cn
Keywords: quantitative structure-spectrum relationship (QSSR), 13C NMR chemical shifts of alcohols and thiols, atomic ionicity index (INI), polarizability effect index (PEI), stereoscopic effect parameters (Оµ)
Abstract
Quantitative structure-spectrum relationship calculations of 13C NMR chemical shifts of both 302 carbon atoms in 56 alcohols and 62 carbon atoms in 15 thiols are described using several parameters: the atomic ionicity index (INI), the polarizability effect index (PEI), and stereoscopic effect parameters (ε) of the compounds. The 13C NMR chemical shifts for these compounds of both alcohols and thiols can be estimated through the multiple linear regression (MLR). A MLR model was built with variable screening by the stepwise multiple regression and examined by validation on its stability. The correlation coefficient of the established model as well as the leave-one-out cross-validation was 0.9724 and 0.9716 respectively. The results obviously indicate that INI and e are linearly related with 13C NMR chemical shifts, which provides a new method for calculating 13C NMR chemical shifts in the compounds of both alcohols and thiols.
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