Concerning the nonexistence of the intramolecular hydrogen bond in 2-nitrothiophenol

Abstract

The long-range spin–spin coupling constants between the sulfhydryl proton and the ring protons in 2-nitrothiophenol in CDCl3 and C6D6 solutions suggest the presence of two conformers in which the S—H bond prefers the benzene plane. The conformer in which the S—H bond lies trans to the nitro group is favoured over the cis conformer by a free energy difference of 0.5 ± 0.2 kcal/mol at 305 K. Apparently any intramolecular hydrogen bond is very weak compared to that in 2-nitrophenol.