用半经验量子化学AM1方法对天然苝醌化合物痂囊腔菌素A(EA)的分子构型和分子内氢键进行了研究；从EA可能的64种构型中选择16种进行了计算.结果表明,EA的X射线晶体结构对应的构型是Ⅱ型左旋(A)a,a型(Ⅱ-L-A-a,a)；小的生成热差值可以使得异构体间的转换容易进行,有利于发生分子内质子传递.尽管采用AM1方法计算得到的EA各种构象的平面性有所差别,但都很接近晶体的平面性.此外,EA分子内氢键键能的平均值为22.9 kJ/mol；Ⅱ型的氢键键能比Ⅰ型的大,(9,10)位的氢键键能比(3,4)位的大；EA的平面性是由苝醌环上的侧链取代所决定,而与分子内是否存在氢键无关.%The molecular configuration and intra-molecular hydrogen bond of natural peryle-nequinone elsinochrome A (EA) were examined with semi-empirical quantum chemical method AMI. Sixteen configurations were selected from 64 possible configurations and calculated. Results indicate that the X-ray crystal structure of EA corresponds to type-II left-hand rotation a, a configuration (II-L-A-a.a). A small difference in formation heat allows easy inter-transformation among various isomers, which facilitates intra-molecular proton transfer. Besides, though the planarities of EA configurations calculated with AM1 method are somewhat different, they are all similar to those of X-ray crystals. Moreover, the average intra-molecular hydrogen bond energy of EA is 22. 9 kj/mol. The hydrogen bond energies of type-II configuration are larger than that of type-I configuration, while hydrogen bond energies at (9,10) positions are greater than that at (3,4) positions. Furthermore, the planarity of EA is determined by side-chain substitution on perylenequinone ring and is not dependent on whether or not intramolecular hydrogen bond exists.
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