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为了研究X-CH_2-CH_2-X(X=H,CH_3,OH,NH_2,SH,F,Cl,Br)的构象,采用密度泛函理论的量子化学计算方法,扫描其势能而,分析其典型构象,——得出稳定构象,并分析了最影响其稳定构象的原因。结果表明,对于正丁烷、1,2-二氯乙烷、1,2-二溴乙烷和乙二巯醇,对位交叉构象最稳定,影响其最稳定构象的主要因素是空间作用:对于乙二醇,乙二胺,邻位交叉式为其最稳定的构象,该构象稳定的主要因素是分子内氢键;偶极-偶极相互作用导致1,2-二氟乙烷的最稳定构象是邻位交叉式;超共轭作用导致乙烷的最稳定构象为对位交叉。用理论化学计算,可以确定分子的最稳定构象,应从多方面分析影响分子最稳定构象的原因。
In order to study the conformation of X-CH_2-CH_2-X (X = H, CH_3, OH, NH_2, SH, F, Cl, Br) Conformation, - a stable conformation is obtained and the reason that most affects its stable conformation is analyzed. The results show that for n-butane, 1,2-dichloroethane, 1,2-dibromoethane and ethanedynol, the main reason for the most stable conformation of the para-positional cross-over conformation is the steric effect: For ethylene glycol, ethylenediamine, the ortho-cross is the most stable conformation, the main factor for the conformational stability is intramolecular hydrogen bonding; dipole-dipole interaction leads to the most stable 1,2-difluoroethane The stable conformation is ortho-crossed; hyperconjugation leads to the most stable conformation of ethane as a para-position crossover. With theoretical calculations, the most stable conformation of a molecule can be determined, and the reasons that influence the most stable conformation of the molecule should be analyzed in many ways.