The mechanism of the photochemical formation of tricyclo{6.4.0.0('2,7)}7,8-cis-dodec-1-ene (CB), 1'-methoxybicyclohex-1-ene (1,2 ET), and a new product, 2'-methoxybicyclohex-1-ene (1,4ET), from the sensitized irradiation of 1,1-bicyclohexenyl (BCH) in methanol has been investigated using steady state kinetic techniques. The effects of added acid, sensitizer energy, methanol concentration, BCH concentration, and temperature on the product quantum yields were evaluated. The solvent deuterium isotope effect on the product quantum yields was measured. Correlation of the steady state results with transient absorption flash spectroscopic measurements performed in collaboration with R. Bonneau (University of Bordeux, France) has provided proof that the intermediate responsible for all of the observed photochemistry is a strained ground state twisted transoid isomer of BCH, c,t-BCH, formed from the BCH triplet state. Reaction of c,t-BCH with methanol gives the methyl ethers, 1,2 ET and 1,4 ET. Cyclobutene (CB) formation occurs by a conrotatory electrocyclization of c,t-BCH. / The mechanism of photoproduct formation from the direct irradiation of BCH has also been investigated. The observed photoproducts are CB, 1,2 ET, 1,4 ET and 1,3'-bicyclohexenyl (UD). Steady state photochemical measurements of product quantum yields provide evidence that methanol addition to c,t-BCH formed from a BCH excited singlet state accounts for all of the observed ether formation. A reaction pathway to CB independent of c,t-BCH accounts for 36% of the observed CB formation. The formation of UD is consistent with its production from a BCH excited singlet state. The effects of changing the excitation wavelength on the CB/UD product ratio is discussed on the basis of ground state s-cis - s-trans conformational control of the photochemistry. / Source: Dissertation Abstracts International, Volume: 45-06, Section: B, page: 1780. / Thesis (Ph.D.)--The Florida State University, 1984.
| Identifer | oai:union.ndltd.org:fsu.edu/oai:fsu.digital.flvc.org:fsu_75346 |
| Contributors | MARCHAND, GARY ROBERT., Florida State University |
| Source Sets | Florida State University |
| Detected Language | English |
| Type | Text |
| Format | 324 p. |
| Rights | On campus use only. |
| Relation | Dissertation Abstracts International |
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