These tools will no longer be maintained as of December 31, 2024. Archived website can be found here. PubMed4Hh GitHub repository can be found here. Contact NLM Customer Service if you have questions.
Pubmed for Handhelds
PUBMED FOR HANDHELDS
Search MEDLINE/PubMed
Title: Stability and thermal rearrangement of (E,E)-1,3-cycloheptadiene and trans-bicyclo[3.2.0]hept-6-ene. Author: Qin C, Davis SR, Zhao Z, Magers DH. Journal: J Phys Chem A; 2006 Feb 09; 110(5):2034-8. PubMed ID: 16451039. Abstract: The highly strained (E,E)-1,3-cycloheptadiene was shown to be a minimum on the potential energy surface; two structural isomers were found at the MP2 level, but multiconfiguration self-consistent field calculations show that only one is a true minimum. The isomerization of (E,E)-1,3-cycloheptadiene was investigated through double bond rotation, and electrocyclic ring closure. The first pathway gives (E,Z)-1,3-cycloheptadiene, with a barrier of 7.2 kcal x mol(-1), and the second pathway gives the trans isomer of bicyclo[3.2.0]hept-6-ene with a barrier of 13.0 kcal x mol(-1). The strain energy of (E,E)-1,3-cycloheptadiene was calculated using homodesmotic reactions and found to be about 96 kcal x mol(-1) whereas that for (E,Z)-1,3-cycloheptadiene was only 38 kcal x mol(-1), implying that the second trans double bond imparts an additional 58 kcal x mol(-1) in strain energy. The trans isomer of bicyclo[3.2.0]hept-6-ene was calculated to have a strain energy of 69 kcal x mol(-1) and a barrier of 27 kcal x mol(-1) for isomerization to (Z,Z)-1,3-cycloheptadiene. Although many of the structures reported here could be described using a single determinant wave function, several could not, making a multireference method necessary for a complete description of the potential energy surface.[Abstract] [Full Text] [Related] [New Search]