Assignment of carbon-sulphur vibrations by selenation: an FT-IR and FT-Raman study on 1,3,5-trithiacyclohexane

ARCA, MASSIMILIANO;GARAU A.;ISAIA, FRANCESCO;LIPPOLIS, VITO

1996-01-01

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Abstract

The IR and Raman spectra of 1,3,5-trithiaeyclohexane (1) and 1,3,5-triselenocyclohexane (2) have been recorded with FT-instrumentation within 3500-100 cm(-1), and the C-S vibrations of 1 have been reviewed by comparing its spectra with those of 2. The IR and Raman spectra slightly differ from those previously reported and some vibrations, previously assigned to C-H modes in 1 on the basis of NCT calculations, are reassigned to C-S modes on the basis of the selenation effect. ''Selenation'' has proved to be a very simple and effective tool in recognizing carbon-sulfur vibrations both in IR and Raman. The Raman peaks due to carbon-chalcogen vibrations are less intense in 1 than in 2, according to the higher polarizability of the selenium atom.