Experimental and theoretical IR study of methyl thioglycolate, CH₃OC(O)CH₂SH, in different phases: Evidence of a dimer formation

Yanina B. Bava (1) , Luciana M. Tamone (1) , Luciana C. Juncal (1) , Samantha Seng (2) , Yeny A. Tobón (2) , Sophie Sobanska (2) , A. Lorena Picone (1) , Rosana M. Romano (1)

1 CEQUINOR - Centro de Química Inorgánica "Prof. Dr. Pedro J. Aymonino" [La Plata]
2 LASIRE - Laboratoire Avancé de Spectroscopie pour les Intéractions la Réactivité et l'Environnement - UMR 8516

The IR spectrum of methyl thioglycolate (MTG) was studied in three different phases, and interpreted with the aid of DFT calculations. The gas phase IR spectrum was explainable by the presence of the most stable conformer (syn-gauche-(-)gauche) only, while the IR spectrum of the liquid reveals strong intermolecular interactions, coincident with the formation of a dimeric form. The matrix-isolated spectra allow the identification of the second conformer (syn-gauche-gauche), in addition to the most stable form. The MTG dimer was also isolated by increasing the proportion of MTG in the matrix. The theoretical most stable structure of the dimer, which calculated IR spectrum agrees very well with the experimental one, is stabilized by a double interaction of the lone pair of the O atom of each of the C[dbnd]O groups with the antibonding orbitals σ* (S[sbnd]H).

Mots clés: Conformational analysis; Dimers; IR

Domaines: Chimie théorique et/ou physique

Yanina B. Bava, Luciana M. Tamone, Luciana C. Juncal, Samantha Seng, Yeny A. Tobón, et al.. Experimental and theoretical IR study of methyl thioglycolate, CH₃OC(O)CH₂SH, in different phases: Evidence of a dimer formation. Journal of Molecular Structure, 2017, 1139, pp.160 - 165. ⟨10.1016/j.molstruc.2017.03.031⟩. ⟨hal-01579622⟩