苯并七元环硫代亚硫酸酯核磁共振谱的理论研究

应用密度泛函方法对新合成的苯并七元环硫代亚硫酸酯分子的平衡几何构型进行了优化.用从头算法和密度泛函方法计算了碳和氢的化学位移,并与实验结果进行了比较.结果表明,从头算法得到的七元环亚甲基上氢的化学位移理论值和实验值符合得很好.理论值一方面可以对七元环上四个氢的化学位移做出指认,另一方面也对SS键引起的亚甲基上氢的非对映异位给出解释.密度泛函方法定性地区分了亚甲基上两个氢的不同,对碳的化学位移计算要比从头算法稍好.

Theoretical Study on NMR for Thionosulfite

Geometries of the newly synthesized seven-membered-ring thionosulfites have been optimized by density functional theory (DFT).The chemical shifts of 1H and 13C have been calculated with ab initio and DFT, all of which are compared with the experimental results. It shows that theoretically predicted chemical shifts of hydrogen atoms in methylene in seven-membered ring are in good agreement with experimental values. Theoretical values can not only assign the hydrogen chemical shifts in seven-membered ring, but also explain diastereotopic effect of hydrogen in methylene caused by SS bond. The DFT method qualitatively distinguishes the two hydrogen atoms in methylene, and the results for carbon are better than those determined by ab initio method.