二苯醚的势能面与构象研究

THE STUDEIS ON THE ROTATION POTENTIAL SURFACE AND CONFIGURATION OF DIPHENYL ETHER

聚苯醚是具有多元重复氧桥结构的化合物。对这类体系的构象研究是一个很有意义的课题,如最简单的聚苯醚——二苯醚,文献中已提出三种不同的构象模型。Smyth等人认为,二苯醚中两苯环都垂直于C-O-C平面,即θ=φ=90°(见图1,θ,φ分别为两个苯环与C-O-C平面的夹角)。Sutton等人根据Pauling的假设认为,二苯醚中两个苯环共平面,即θ=φ=0。这样氧原子上孤对电子可参与共轭,使分子趋于稳定。Higgasi等人利用键矩加合规则,假定C-O-C键角为118°,计算了2,4,二取代甲基二苯醚及2,4。

The molecular configuration of diphenyl ether has been studied by MNDO method, The most stable configuration of diphenyl ether was obtained by means of optimization of molecular geometric configuration. The rotational potential surface describing internal rotation about the two C—O bond of diphenyl ether was drawn. The calculated results show that the minimum of the rotation potential surface is at θ=φ=65°, ∠COC=120.46° and the two benzene rings are easy to rotate about the two C—O bond within certain range. The three configurations which had been considered as the most stable configuration are discussed in this paper.