Yo Ueda

Organic analysis-XV1: The infrared spectra of the tetralin series

Abstract The out-of-plane CH deformation vibrations of the aromatic ring of the tetralin series normally appear in almost the same frequency region as in the corresponding benzene series, and their frequencies are regularly shifted by the type of substituents attached to the aromatic ring with a few exceptions. All compounds which have an isolated CH group in the aromatic ring exhibit fairly strong absorption bands around the 800 cm−1 region, which may be associated with the aromatic ring. Carbonyl and hydroxyl groups in the peri-position of tetralone are strongly chelated, showing frequency shifts in their stretching vibrations.

Studies on Tetralin Derivatives. III

Ten kinds of hydroxytetralone oximes have been synthesized and their reactions with metallic ions have been investigated. It was found that the tetralone oxime having a hydroxyl group at the 8-position reacted with Cu2+, Ni2+, and Co2+, etc., forming insoluble, colored precipitates; but those containing no hydroxyl group at the 8-position or those having inactivated 8-methoxy or 8-acetoxy groups did not form the precipitate. The precipitate was found to be an intramolecular complex salt of the metal and the oxime by analysis of the compound and from the solubility of the precipitate in chloroform. 8-Hydroxy-5-methoxytetralone oxime had an especially sensitive reaction with metallic ions, and this could be utilized as a spot test reagent. Also, the chloroform solution of the complex salt of this oxime with Cu2+ and Ni2+ gave light yellow and light green colorations withmaximum absorption at 378 mμ and 395 mμ, respectively. The light absorbancy and the ion concentration were linearly related, and this relationship could be utilized in colorimetric determin ations of Cu2+. and Ni2+. The complex salt of Co2+ had an orange color and showed maximum absor ption at 372.5 mμ; but it changed gradually to dark brown, and the absorption finally became obscure.