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提出以原子电性距离矢量 (VAED)描述各种碱基分子中不同等价碳原子的化学环境 ,结合γ效应校正与碳原子类型 ,建立核磁共振碳谱 ( 1 3CNMR)化学位移 (CS)的五参数线性模型 .用于碱基分子中 4类不同碳 (其中主要是仲叔季碳 )的等价碳原子化学位移的估计 ,复相关系数R和均方根误差RMS[ppm]分别为仲叔季碳 :1 )对C2n =1 2 ,R =0 .9998,R2 =0 .9997,F =2 732 .2 4 98,EV =0 .9994,RMS =0 .1 80 4 ,SD =0 .1 8842 )对C3n =41 ,R =0 .9334,R2 =0 .871 2 ,F =38.32 99,EV =0 .852 8,RMS =9.52 68,SD =9.64523)对C4n =2 3,R =0 .91 83,R2 =0 .8433,F =1 4.3479,EV =0 .7972 ,RMS =6.530 4 ,SD =6.67721 )对C2n =1 2 ,R =0 .9998,R2 =0 .9997,F =2 592 .70 72 ,EV =0 .9994,RMS =0 .1 852 ,SD =0 .1 9342 )对C3n =41 ,R =0 .92 70 ,R2 =0 .8594,F =34.62 83,EV =0 .8393,RMS =9.548,SD =1 0 .0 7843)对C4n =2 3,R =0 .90 71 ,R2 =0 .82 2 9,F =1 2 .3881 ,EV =0 .770 8,RMS =6.942 5,SD =7.0 985经交互校验 ,模拟稳定性较好 .并综合几种处理方法 ,找到一种较好的建模方法 ,将它用于 4个外部样本化学位移的定量预测 ,结果良好
The chemical environment of different equivalent carbon atoms in various base molecules is described by the atomic valence distance vector (VAED). The chemical shift (CS) of 13 C NMR spectra is established by combining gamma effect correction and carbon atom type A five-parameter linear model is used to estimate the chemical shifts of the equivalent carbon atoms of four different carbons (mainly secondary tertiary quaternary carbons) in the base molecule. The complex correlation coefficient R and the root mean square error RMS [ppm] Tert-season carbons: 1) For C2n = 1 2, R = 0.9998, R2 = 0.9997, F = 2 732.2988, EV = 0.9994, RMS = 0.8180, SD = 0 .1 8842) for C4n = 2 3, Rn = 3, R = 0 .9334, R2 = 0.881 2, F = 38.3299, EV = 0.852 8, RMS = 9.52 68, SD = 9.64523) = 0.9183, R2 = 0.8433, F = 1 4.3479, EV = 0.7972, RMS = 6.530 4, SD = 6.67721) For C2n = 1 2, R = 0.9998, R2 = 0.9997, F = 2 592 .70 72, EV = 0.9994, RMS = 0.852, SD = 0.19342) For C3n = 41, R = 0.92 70, R2 = 0.8594, F = 34.62 83 , EV = 0.83393, RMS = 9.548, SD = 1.08743) for C4n = 2 3, R = 0.9071, R2 = 0.82 2 9, F = 1 2 .3881, EV = 0 .770 8, RMS = 6.942 5, SD = 7.0 985 After verification, the simulation stability is better. We found a good modeling method and used it to quantitatively predict the chemical shifts of four external samples with good results