SH···S H‐Bonded Ethanethiol Clusters in Cold Argon and Nitrogen Matrices: An IR Spectroscopic Study

The conformational behavior of SH···S H‐bonded ethanethiol (EtSH) dimer and trimer has been experimentally studied in cold and solid argon (Ar) and nitrogen (N 2 ) matrices via analysis of the spectral region. Over 20 spectral bands were observed in both matrices exhibiting a wide range of spectral shifts (4.8–87.5 cm −1 ). Their spectral assignment was supported by normal mode frequencies calculated at the ωB97X‐D/aug‐cc‐pV(D + d)Z level of theory, which displayed close match. Calculations predicted 24 (EtSH) 2 conformers belonging to four classes ( GG , GG′ , GA , and AA ) and 45 (EtSH) 3 conformers from seven classes ( GGG , GGG′ , GG′G′ , GGA , GG′A , GAA , and AAA ) formed by gauche ( G and G’ ) and anti ( A ) monomers. Experimentally, 16 dimers and 9 trimers were identified as the relative stability showed small variation; only 1.42 and 2.77 kcal mol −1 for dimer and trimer. However, no AA dimer as well as GAA and AAA trimer could be identified in any matrix, due to the presence of multiple lesser stable A monomers. The most stable conformers were found to possess weaker and longer SH···S H‐bonds, while the lesser stable conformers possessed stronger and shorter SH···S H‐bonds. When compared against SH···S H‐bonds in H 2 S clusters, the ones in EtSH clusters showed markedly greater contribution of dispersion interaction.