二氯代丁二烯的内旋转

Internal Rotations in Some Dichlorobutadiene Molecules

采用DFT B3LYP方法和6-311G(d,p)基组研究了3种二氯代丁二烯分子((t,t)-1,4-DCBD,(c,c)-1,4-DCBD,2,3-DCBD)的内旋转.计算结果表明,3种分子发生内旋转的势能曲线具有相同的形状:在势能曲线上有2个能量极小点,分别为s-trans和s-gauche构型;有2个过渡态构型;s-trans构型是能量最低构型.(c,c)-1,4-DCBD的s-trans构型比(t,t-)1,4-DCBD的s-trans构型稳定,与实验结果相符合.

Internal rotations in（t,t）-1,4-DCBD（dichlorobutadiene）,（c,c）-1,4-DCBD,and 2,3-DCBD molecules are studied by using the DFT B3LYP method in combining with the 6-311G（d,p） basis set.The calculated internal rotation potential energy curves（PECs） for the three molecules have the similar trend： there exist the s-trans and s-gauche minima and the two transition states on the PECs.The s-trans conformers are the lowest energy conformers among all three molecules.The s-trans conformer of（c,c）-1,4-DCBD is predicted to be more stable than that of（t,t）-1,4-DCBD,which is in line with the experimental results.