紫外线吸收剂邻羟基二苯甲酮优势构象的研究

采用密度泛函法在B3LYP/6-311G(d,p)水平上研究邻羟基二苯甲酮几种构象异构体的相互转化过程。通过研究得到各驻点的几何结构和能量值,发现4种构象异构体在常温下可以相互转换,其中IM1中有分子内氢键,能量最低,为绝对优势构象。为进一步确定其在氯仿溶剂中的优势构象,采用GIAO法在相同的水平上对优化好的中间体进行NMR理论计算,通过将理论计算得到的1 H NMR化学位移值与实验值进行对比,发现构象异构体IM1的1 H NMR化学位移计算值与实验值相符合,从而确定IM1也为实际中的最优势构象。

Preferred conformation of UV absorber-2-hydroxybenzophenone

Isomerization processes of several conformers of 2-hydroxybenzophenone were investigated with density functional methods at the B3LYP/6-311G(d,p) level. It is found through the analysis of the geometric structures and energies obtained that the four conformers at room temperature can isomerize to each other. Among the four conformers, the conformer IM1possesses intramolecular hydrogen bond and the lowest energy and is the predominant conformer. In order to determine the preferred conformer of 2-hydroxybenzophenone in the CHCl₃, the GIAO method on the same base set was employed to study ¹H NMR. The comparison of the calculated ¹H NMR chemical shift values with experimental data finds that the theoretical ¹H NMR chemical shift of IM1is close to experimental values; therefore, IM1is the most preferred conformer in practice.