2,2’-二甲基-4,4’-联噻唑与CHCl3分子间相互作用的理论研究

采用量子化学从头算理论在MP2/6-31G(d,p)水平上对2,2’-二甲基-4,4’-联噻唑顺反异构体, trans-2,2’-二甲基-4,4’-联噻唑-CHCl3 (I), cis-2,2’-二甲基-4,4’-联噻唑-CHCl3 (II)形成的1∶1氢键复合物进行计算研究. 结果表明, 2,2’-二甲基-4,4’-联噻唑在气相条件下, 反式构象比顺式构象稳定. 氯仿与2,2’-二甲基-4,4’-联噻唑形成的复合物存在较强的氢键, 表现为氮原子的孤对电子与氯仿分子中C—H反键σ轨道的相互作用, 另外形成C—H…Cl弱相互作用, 氢键作用使2,2’-二甲基-4,4’-联噻唑的顺式结构在氯仿溶剂比反式结构更稳定.

Theoretical Research on Intermolecular Interaction between 2,2'-Dimethyl-4,4'-bithiazole and Chloroform

The cis-trans isomers of 2,2’-dimethyl-4,4’-bithiazole, 1∶1 hydrogen-bond complex (I) between trans-2,2’-dimethyl-4,4’-bithiazole and chloroform, and hydrogen-bond complex (II) between cis-2,2’- dimethyl-4,4’-bithiazole and chloroform were studied by using ab initio calculation at MP2/6-31G(d,p) basis set level. The results showed that in the gas phase, trans-2,2’-dimethyl-4,4’-bithiazole was more stable than cis-2,2’-dimethyl-4,4’-bithiazole. There are strong hydrogen-bonds existing in the 1∶1 hydrogen-bond complexes, as interaction between the lone pair electrons on the N atom and σ*(C—H) antibonding orbitals in chloroform molecule, as well as weak interaction between C—H and Cl. The existing hydrogen-bonds made cis-2,2’-dimethyl-4,4’-bithiazole more stable in chloroform solvent.