The molecular structure and conformations of 3-ethenyl-3-methyl-cyclopropene as determined by ab initio calculations and gas-phase electron diffraction
| Autor: | Vladimir S. Mastryukov, Marit Trætteberg, Pirkko Bakken, Ilia Kuchuk, I. G. Bolesov, Armin de Meijere |
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| Rok vydání: | 1998 |
| Předmět: |
010405 organic chemistry
Chemistry Gas electron diffraction Organic Chemistry Ab initio Cyclopropene 010402 general chemistry 01 natural sciences 0104 chemical sciences Analytical Chemistry Gas phase Inorganic Chemistry Crystallography chemistry.chemical_compound Electron diffraction Ab initio quantum chemistry methods Molecule Spectroscopy |
| Zdroj: | Journal of Molecular Structure. 445:107-115 |
| ISSN: | 0022-2860 |
| DOI: | 10.1016/s0022-2860(98)00417-7 |
| Popis: | The molecular structure and conformation of 3-ethenyl-3-methyl-cyclopropene have been studied experimentally by the gas electron diffraction method. A conformational mixture consisting of 75.4(3.1)% anti (ω(C 3 C 4 ): 180°) and 24.6% gauche (ω(C 3 C 4 ): 52.2(4.6)°) was observed. Theoretical ab initio optimization calculations at the MP 2 6–31 G ∗ level have also been performed. They include a potential scan which showed two energy minima, one at ω(C 3 C 4 ) equal to 180° ( anti ) and the other at ω(C 3 C 4 ) equal to ± 20.3° ( gauche ). The calculated energy difference between the two minima was 1.03 kcal/mol, with anti as the lower minimum. This corresponds to a conformational composition of 73.3% anti and 26.7% gauche , in excellent agreement with the experimental results. The gauche → anti and anti → gauche potential barriers were calculated to be 2.3 and 3.4 kcal/mol, respectively. |
| Databáze: | OpenAIRE |
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