Anomalous behaviour of 18O-labelled compounds. Part 15.—Integrated intensity of the A1 Raman bands of 18O-labelled trisacetylacetonatochromium(III) as compared with that of the normal complex bands

Abstract

The Raman spectra of dilute methylene chloride solutions of normal and 84 atom %¹⁸O-labelled acetylacetonatochromium were measured in the 50–3200 cm^–1 region. The relative intensity of the polarised (A₁ species) Raman bands of the normal complex solution observed thus was compared with that of the corresponding ¹⁸O-labelled complex solution bands and was found in each case to be appreciably lower. The value of the [graphic omitted] I^R_α/ω_α sum for these bands (where I^R_α is the relative integrated intensity of such a band and ω_α is its frequency) which theoretically is expected to be approximately the same in both cases was found to be larger for the ¹⁸O-labelled complex by ≈ 200 %. This fact might be the result of a different polarisability for the ¹⁸O—Cr bonds from that of the respective ¹⁶O—Cr bonds.