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本文用MNDO和FHMO(Fenskc-Hall MO)研究了2,3-缩水-4,6-双-氧(对-X苄基)-2-D异头吡喃葡糖甲苷(MX_2A,X=H,F,Cl,Br,I)的结构。用MNDO优化出的MH_2A的键长,键角和二面角和MBr_2A的晶体数据极为接近。计算出了三个取代基的分子内旋转势垒,都有二个极大值。高度约10～350(Kcal/mol)。HOMO是MO69,但和MO66,67,68极为接近,相差只有10(Kcal/mol),而且都是由二个苯环的Pz AO组成。糖苷基上的2-3桥氧原子由于张力,净电荷只有-0.24(电子),而其余三个氧原子都有-0.34～-0.40(电子)电荷。
In this paper, the effects of 2,3-dimorphic-4,6-bis-oxo (p-Xbenzyl) -2-D isoglucopyranoside (MX_2A, X = H, F, Cl, Br, I). The bond length, bond angle and dihedral angle of MH_2A optimized by MNDO are close to the crystal data of MBr_2A. The intramolecular rotational barriers of three substituents were calculated, each with two maxima. Height about 10 ~ 350 (Kcal / mol). HOMO is MO69, but it is very close to MO66, 67 and 68, with a difference of only 10 (Kcal / mol). Both of them are composed of Pz AO of two benzene rings. The 2-3 bridging oxygen atoms on the glycoside have a net charge of only -0.24 (electrons) due to the tension and a -0.34 ~ -0.40 (electron) charge of the remaining three oxygen atoms.