Molecular Vibrations and Force Fields of Alkyl Sulfides. VI. Methyl Ethyl Sulfide and Its Deuterated Compounds, and Diethyl Sulfide

Abstract

Abstract Deuterated methyl ethyl sulfides, CD3SCH2CH3 and CH3SCD2CD3, were prepared, and their infrared spectra were recorded in the gaseous, liquid, and solid states. The normal coordinates of methyl ethyl sulfide, its deuterated analogues, and diethyl sulfide have been treated by the use of a modified Urey-Bradley potential field. The conformational analyses of these sulfides were made by the aid of the calculations. In the gaseous and liquid states, two forms (T and G) have been confirmed to exist for CH3SCH2CH3, and three forms (TT, TG, and GG), for CH3CH2SCH2CH3. In the solid state, CH3SCH2CH3 or CH3CH2SCH2CH3 exists in one form: T or TT. The observed infrared frequencies were compared with the calculated frequencies and were fully assigned.