Photoisomerization of 1,6-Heptadiene Sensitized by Mercury 6(³ P₁ ) Atoms

Abstract

The decomposition of 1,6-heptadiene photosensitized by mercury 6(3 P1 ) atoms has been studied in the pressure range from 3 to 65 mm. In addition to free-radical products and a polymer which accounted for 95% of the decomposition, six isomers were observed. Four of these were identified as 4-cyclopropylbutene-1, bicyclo[3.2.0]heptane, bicyclo[3.1.1]heptane, and 1-methyl-2-vinylcyclobutane. Thus, in this system, an isomerization which gives rise to a cyclopropyl derivative (as in other unconjugated diolefins) as well as a parallel process which gives a cyclobutyl derivative (as in monoolefins) are observed. It is tentatively suggested that the present system may not be unique in this respect and that two such pathways may be operative in the mercury-photosensitized isomerization of other unconjugated diolefins as well. © 1965, American Chemical Society. All rights reserved.