RAMAN AND INFRARED SPECTRAL STUDIES OF SELENA, SULFINYL, SULFONYL ANDTELLURA METHYL LAURATES

Raman spectra (300-1200 cm(-1)) have been recorded for all the positio nal isomers of the selena (X = Se), sulphinyl (X = SO) and sulphonyl ( X = SO2) methyl laurates CH3(CH2)(u)X(CH2)(m)CO2CH3, (n + m = 9). The Raman spectra of two isomers of the tellura series (X = Te) were also obtained as were the IR spectra of the sulphonyl series. The SeC2 and TeC2 moieties each give two characteristic Raman bands at 564 and 651 cm(-1) and 510 and 600 cm(-1) respectively. The SO group gives a chara cteristic Raman band at 1016 cm(-1). The symmetric stretching and bend ing modes of the SO2 group can be observed in both the IR and Raman sp ectra at 1109 and 517 cm(-1) respectively. These quoted values do chan ge when the functional group is near the carbonyl group or towards the end of the alkyl chain. (C) 1997 Elsevier Science Ireland Ltd.