层叠苯环π-π相互作用的理论研究  

Theoretical Study on the π-π Interactions in Stacked Benzene Molecules

作　　者：范育波[1] 陶凤岗[1] 徐伟[2] 华中一[2] 

机构地区：[1]复旦大学化学系,上海200433 [2]复旦大学材料科学系,上海200433

出　　处：《化学学报》1999年第1期1-4,共4页Acta Chimica Sinica

基　　金：国家自然科学基金资助项目(59703003);教育部重点科技项目资助

摘　　要：利用DFT B3LYP/3-21G方法,对多个平行重叠排列的苯环体系进行研究.计算结果发现,平行苯环对称中心的距离(d)在0.40～0.46nm之间时,苯环以倾斜的方式层叠,即平行移位结购排列,体系能量有最小值,苯环平面的法线与各苯环中心连线的夹角(A)根据距离的不同分别为:d=0.40nm,A=25°;d=0.42nm,A=29°;d=0.44nm,A=34°d=0.46nm,A=40°.此结果与聚苯乙烯STM图像中苯环的排列结构十分吻合,测得值:d=0.43nm,A=25～30°.In this paper, the parallel-stacked benzene molecules has been studied by DFT B3LYP method using 3-21G* basis set. The calculated system is composed of five benzene molecules,which stand face to face in a straight line, and this system looks like a stack of pennies. When the distance (d) between the centers of every next benzene molecules is arranged with a certain value ranging from 0.40 ran to 0.46 nm, it is found that the energy of the system varies with the changing of the angle ( A ) between the normal of benzene planes and the line through the centers of every benzene molecules. The existence of the energy minimums indicates the most favorable correlation between d and A is as follows: d = 0.40 nm, A =25°; d =0.42nm,A= 29°; d = 0.44nm,A = 34°; d = 0.46nm, A= 40° (Shown in Fig.3).The calculated system may find its application in the field of the π-π interaction in polymer. A typical example is the interaction between the phenyl groups of polystyrene, where the polymer chain skeleton adopts a unique conformation, such as TGTG. The calculated result is in a good agreement with experimental evidence from the observation of polystyrene micro - particles by scanning tunneling microscopy (STM) .The STM image shows that the phenyl groups of polystyrene stack up as a parallel-displaced structure, the measured d is 0.42~ 0.44 nm, while the measured A is 25° ~ 30°.

关 键 词：苯 构象 DFT 聚苯乙烯 Π-Π相互作用 层叠苯环 

分 类 号：O632.13[理学—高分子化学] O621.13[理学—化学]