Calculated Structures and Relative Stabilities of Furoxan, Some 1,2-Dinitrosoethylenes and Other Isomers

摘要

The structures and relative stabilities of furoxan and some of its isomers, e.g.the 1,2-dinitrosoethylenes, have been determined by means of ab initio Hartree-Fock and Moller-Plesset calculations. Geometries were optimized at the HF/3-21G, HF/6-31G* and MP4/6-31G* levels, and subsequently used for computing MP2/6-31G*,MP3/6-31G* and MP4/6-31G* energies. The results are markedly affected by the inclusion of electronic correlation, which renders three of the isomers unstable. It also emphasizes the importance of a zwitterionic contribution to the structure of furoxan, which promotes ring-opening through a cis 1,2-dinitrosoethylene intermediate/transition state that has an MP4/6-3 1 G*//MP2/6-31G* energy that is 31.6 kcal/mole above furoxan. Furoxan, 1,2-Dinitrosoethylenes, Structures, Stabilities, Ab initio HF and MP calculations.