电负性效应、极化效应和立体效应对脂肪胺核磁共振谱化学位移的影响

Influence of Electronegativity,Polarizability and Steric Effects on the ^(13)C Nuclear Magnetic Resonance Chemical Shift of Aliphatic Amines

用原子电负性、极化度并结合表征原子空间连接方式的立体效应参数对胺分子中不同环境碳原子的化学位移进行关联,将75脂肪胺(54个脂肪一元胺,21个二元胺)中307个碳原子相关参数值和化学位移值带入模型中得到如下估算方程:δC=116.9506+96.7412Qi-3.7464Qi∑αx-24.3581SH-7.6858SN(R=0.9943,R2=0.9887,S=1.51,F=6612.73,n=307),式中Qi表示观测原子的部分净电荷,∑αx表示近邻原子极化度,SH,SN为立体效应参数,方程中各参数计算简单,物理意义比较明确,通过用"留一法"(LOO)检验(Rcv=0.9940,R2cv=0.9881,Scv=1.54)及对样本外11个化合物55个碳原子化学位移的预测值和实验值比较,结果表明模型方程具有较好的稳定性和预测精度。

The ^13C NMR chemical shift for an given carbon atom in aliphatic amine molecules was related to the atomic eleetronegativity, polarizability and sterie effects of the substituents. The correlation equation between 307 ^13C NMR chemical shift values and the parameters was carried out for 75 aliphatic amines （54 amines and 21 diamines） and the parameters was obtained ：δc = 116. 9506 ＋ 96. 7412Qi - 3. 7464QiΣαx - 24.3581SH -7.6858SN（R =0. 9943, R^2=0. 9887, S = 1.51 , F =6612.73, n =307）. In which, the Qi is the partial net charge of the given atom, Σαx is the polarizability of atoms near the given atom, Sn and SN is the stereoscopic effect parameters. The parameters used in the equation are easily to be calculated and have clear physical meaning. The stability and prediction capacity of the model were tested using leave-one-out （LOO） cross-validation method（Rcv=0. 9940, R^2cv =0.9881, Scv = 1.54）, and conformed by predicting for external compounds（55 different carbon atoms in 11 compounds）.