Theoretical investigation of the conrotatory ring opening oc cyclobutene and 1,2-dihydro-1,2-diazacyclobutadienes with ab initio and density functional Gaussian-type-orbital approach
- Univ. of New Orleans, LA (United States)
The theoretical study of the thermally allowed conrotatory opening of cyclobutene (1) and cis- (2) and trans-1,2-dihydro-1,2-diazacyclobutadiene (3) were performed with ab initio and density functional calculations. The reactants and the transition states were fully optimized by using the 6-31 + G** basis set with RHF, MP2, SVWN, and BLYP methods. The calculated activation barriers for the ring opening of 1 with both MP2 and SVWN incorporating ZPVE correction give extraordinary agreement with the experimental value. The predicted activation energies for 2 and 3 are lower than in the case of the cyclobutene ring opening. Of the two 1,2-dihydro-1,2-diazacyclobutadiene isomers, the trans isomer has a lower activation barrier. The structural and energy differences and the trend among these compounds are interpreted in terms of orbital overlap and steric interactions in the course of the conrotatory ring opening. 18 refs., 11 tabs.
- Sponsoring Organization:
- USDOE
- OSTI ID:
- 482348
- Journal Information:
- International Journal of Quantum Chemistry, Vol. 56, Issue 2; Other Information: PBD: 15 Oct 1995
- Country of Publication:
- United States
- Language:
- English
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