Raman Spectra of Hydrocarbons III. Diisobutylene, Cyclohexene, and Dipentene

Raman frequencies, relative intensities, and depolarization factors are listed for diisobutylene, cyclohexene, and dipentene. The relative intensities and depolarization factors were obtained with the aid of a Gaertner microdensitometer. The results are compared with data previously obtained for six olefins containing the groups XHC=CH2, XYC=CH2, or XHC=CHY (trans). The present compounds contain the groups XYC=CH2, XHC=CHX (cis), and XYC=CHZ. The first of these has nearly the same olefinic frequencies previously found for 2‐methyl‐1‐heptene, except that the 1414 cm−1 frequency of the latter has dropped to 1376. The last two groups were contained in the similar ring structures of cyclohexene and dipentene and had nearly the same frequencies, except that the 1653 and 3023 cm−1 frequencies for XHC=CHX (cis) appeared at 1682 and 3012 for XYC=CHZ. Previous data for the three compounds are collected and compared with the present results. Lack of agreement between the present results in the 1100 and 3000 cm−1 region for diisobutylene and the previous data for 2,4,4‐trimethyl‐1‐pentene is attributed to incorrect assignment of the exciting lines in the previous work.