Prediction of ³¹P nuclear magnetic resonance chemical shifts for phosphines

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• 作者：Jianbo Tong ; Shuling Liu ; Shengwan Zhang ; Shengshi Z. Li
• 关键词：Quantitative structure-spectroscopy relationships (QSSR) ; ³¹P NMR chemical shifts of phosphorus ; Phosphines ; Atomic ionicity index (INI) ; Stereoscopic effect parameters
• 刊名：Spectrochimica Acta Part A ; Molecular and Biomolecular Spectroscopy
• 出版年：2007
• 期刊代码：99_13861425
• 类别：ch
• 出版时间：July 2007
• 卷：67
• 期：3-4
• 页码：837-846
• 文件大小：192 K

摘要

Quantitative relationships of the ³¹P NMR chemical shifts of the phosphorus atoms in 291 phosphines with the atomic ionicity index (INI) and stereoscopic effect parameters (_α, _β, _γ) were primarily investigated in this paper for modeling some fundamental quantitative structure-spectroscopy relationships (QSSR). The results indicated that the ³¹P NMR chemical shifts of phosphines can be described as the quantitative equation by multiple linear regression (MLR): δ_p (ppm) = −174.0197 − 2.6724 INI + 40.4755_α + 15.1141_β − 3.1858_γ, correlation coefficient R = 0.9479, root mean square error (rms) = 13.9, and cross-validated predictive correlation coefficient was found by using the leave-one-out procedure to be Q² = 0.8919. Furthermore, through way of random sampling, the estimative stability and the predictive power of the proposed MLR model were examined by constructing data set randomly into both the internal training set and external test set of 261 and 30 compounds, respectively, and then the chemical shifts were estimated and predicted with the training correlation coefficient R = 0.9467 and rms = 13.4 and the external predicting correlation coefficient Q_ext = 0.9598 and rms = 10.8. A partial least square model was developed that produced R = 0.9466, Q = 0.9407 and Q_ext = 0.9599, respectively. Those good results provided a new, simple, accurate and efficient methodology for calculating ³¹P NMR chemical shifts of phosphines.