Abstract
Spin-coupled (SC) theory was used to investigate the electronic structure of five three-membered rings: cyclopropane (C3H6), aziridine (C2H4NH), ethene oxide (C2H4O), phosphirane (C2H4PH) and thiirane (C2H4S) It is demonstrated that the nuclear frameworks of all five molecules are held together by bent bonds, which gives firm support to one of the two alternative classical models suggested for describing bonding in three-membered rings: the one due to Coulson and Moffitt (the other model, suggested by Walsh, involves the idea of a two-electron three-centre bond). The quantitative character of the SC results is corroborated by the performance of full-valence valence bond (VB) calculations within the active space defined by the SC orbitals. It is argued that the close values of the SC and generalized VB with perfect pairing and strong-orthogonality constraints (GVB-PP-SO) energies for all five systems considered indicates that there is nothing too unusual to distinguish the bonds in three-membered rings from more routine a bonds, say in saturated hydrocarbon chains, except that due to the particular geometry of the nuclear framework the participating orbitals have to bend in order to reduce strain and to be able to overlap more efficiently.
| Original language | English |
|---|---|
| Pages (from-to) | 13-24 |
| Number of pages | 12 |
| Journal | JOURNAL OF MOLECULAR STRUCTURE-THEOCHEM |
| Volume | 341 |
| Publication status | Published - 10 Oct 1995 |
Keywords
- MOLECULAR-STRUCTURE
- ETHYLENE