Experimental (FT-IR, FT-Raman, NMR) and theoretical spectroscopic properties of intermolecular hydrogen bonded 1-acetyl-2-thiohydantoin polymorphs

In this work, use of FT-Raman, FT-IR and 13C NMR spectroscopies have been made for the full characterization of 1-acetyl-2-thiohydantoin (ACTH). A detailed interpretation of the vibrational spectra was carried out with the aid of normal coordinate analysis using single scaling factor. Our results support the hydrogen bonding pattern proposed in the reported crystalline structure. Good reproduction of experimental values is obtained and % error is small in majority of the cases. Isotropic chemical shifts were calculated using gauge-invariant atomic orbital (GIAO) along with several thermodynamic parameters.

In this work, we report a combined experimental and theoretical FT-IR, FT-Raman, UV and NMR spectra along with thermodynamic properties of intermolecular hydrogen bonded 1-acetyl-2-thiohydantoin (ACTH) polymorphs.Figure optionsDownload as PowerPoint slideHighlights
► Experimental and theoretical vibrational and NMR spectra of 2-thiohydantoin are investigated.
► The PED calculation regarding the normal modes provides a strong support for the frequency assignment.
► A remarkable shift in the stretching frequencies of NH and CO bands on moving from monomer to stable system.
► The absorption spectrum has also been calculated in solvent environment using PCM model.
► Solid state 13C NMR were recorded.