Structural and IR-spectroscopic evidence of S-H•••Ph hydrogen bonding in the solid state

Structural and IR spetroscopic evidence is given for S-H ... Ph hydrogen bonding in the solid state, an effect previously only known in solution. In the crystalline thiol N-(o-hydroxyphenyl)-3-sulfanylmethylpyrrolidin-2-one, hydrogen bond energies based on red shifts of the infrared S-H stretching marks are estimated as slightly below 0.5 (in benzene) and 1.0 (solid state) kcal mol(-1).