Study of vibrational spectra and molecular structure of intermolecular hydrogen bonded 2-thiohydantoin using Density Functional Theory

In this work, experimental and theoretical UV, NMR and vibrational spectra of 2-thiohydantoin (2-TH) were studied. We have used a combined FT-IR and FT-Raman spectroscopy along with Density Functional Theory (DFT) to study the effect of hydrogen bonding on molecular structure. Comparison between the gas phase and the solid phase data were also carried out. Our results support the hydrogen bonding pattern proposed by the reported crystal structure and provide valuable information on the structural relationship between the investigated polymorphs. The ultra violet absorption spectra of the compound dissolved in methanol were examined in the range 210–330 nm. The solid state 13C NMR spectra were recorded. Isotropic chemical shifts were calculated using the gauge-invariant atomic orbital (GIAO) method. Comparison of the calculated NMR chemical shifts and absorption wavelengths with the experimental values revealed that DFT method produces good results.