1,1,3,3-四甲基脲—溶剂氢键复合物的理论研究

Theoretical study of hydrogen Bonding complexes for 1,1,3,3-tetramethylurea-solvent

采用密度泛函理论在B3LYP/6-311++G(d,p)水平上对水、苯胺、氯仿与1,1,3,3-四甲基脲分子形成的1:1气相氢键复合物进行计算研究.结果表明,三种物质与1,1,3,3-四甲基脲形成的复合物存在氢键,表现为羰基氧原子的孤对电子与H—X(X=O,N,C)反键轨道的相互作用.氢键的形成使C=O和H—X的伸缩振动频率红移.在标准压力和298.15 K下,氢键复合物的形成是一个放热的非自发过程.

Theoretical studies on molecular interaction between 1,1,3,3-tetramethylurea and water, aniline and chloroform were carried out at 6-311＋＋G（d,p） level using the density functional theory. The result showed that the 1 ： 1 complexes have been formed by hydrogen bonding interaction of lone pairs of oxygen atom with the H--X （X=O,N,C） anti-bonding orbitals of the proton donor. The formation of C = O…H--X hydrogen bond made H--X and C= O stretching vibration frequencies red-shift. It is found that the formation of hydrogen bonding complex was an exothermic and non-spontaneous process at standard pressure and 298.15 K.