Protonated Ethane. A Theoretical Investigation of C2H7+ Structures and Energies

摘要: The C[sub 2]H[sub 7][sup +] potential energy surface was characterized by high-level ab initio calculations. effects of electron correlation on geometries and relative energies are substantial. At MP4(SDTQ)/6-311G**//MP2(full)/6-31G**, the global minimum is C-C protonated structure 1, 4.4 kcal/mol (corrected to 298 K) more stable than C-H form 3. proton affinity ethane give 1 (142.5 kcal/mol) 12.5 greater that methane (130 kcal/mol). Methane adds methyl cation, leading without activation energy. Barriers for intramolecular hydrogen interchange lower dissociation into ethyl cation hydrogen, consistent with experimental observation deuterium scrambling faster dissociation. loses H[sub 2] 1,1-elimination in an endothermic (10.6 process. Three frequencies deduced experimentally correspond those computed but neither 2, 2]-rotated form, nor 3 can explain other set spectral data. Complexes between bridged 5][sup were located, they too weakly bonded be detected experimentally. 45 refs., figs., 9 tabs.