Publication Details (including relevant citation information):
S. Kim, Y. Kwon, J.-P. Lee, S.-Y. Choi, and J. Choo;
Journal of Molecular Structure, 2003, 655, 451.
Theoretical ab initio calculations using the HF and B3LYP methods have been carried out to investigate the conformational differences of three cyclic rings, dibenzo-p-dioxin (DPD), thianthrene (THT), and selenanthrene (SET). The physical origin for the conformational preference of each molecule has been studied using the natural bond orbital (NBO) analysis. The NBO results indicate that DPD exists in a planar form due to strong electron delocalization caused by the specific orbital interaction, nπ → π*CC, around the X atom. On the other hand, THT and SET exist as puckered forms with high inversion barriers due to less effective electron delocalization. The NBO analysis also shows that the conformational stabilization in DPD is caused by a more effective overlap of the 2Pz - π*CC orbitals, compared with the overlap of the 3Pz - π*CC orbitals in THT.
Address (URL): http://dx.doi.org/10.1016/S0022-2860(03)00326-0