Orthogonal hydrogen/halogen bonding in 1-(2-methoxyphenyl)-1H-imidazole-2(3H)-thione-I2 adduct: an experimental and theoretical study

Spectrochim Acta A Mol Biomol Spectrosc. 2015 May 15:143:120-7. doi: 10.1016/j.saa.2015.02.043. Epub 2015 Feb 14.

Abstract

The molecular complex between 1-(2-methoxyphenyl)-1H-imidazole-2(3H)-thione (Hmim(OMe)) and iodine (I2) was investigated. Single crystal of [(Hmim(OMe))I2] adduct was grown by slow evaporation technique from chloroform at room temperature. Spectroscopic techniques such as FT-IR and Raman techniques, as well as elemental and thermal analysis were used to characterize the complex. The crystal structure shows that the formed adduct stabilized by two noncovalent interactions, namely, hydrogen bond (HB) and halogen bond (XB). Orthogonal HB/XB associated with iodine atom (I) was observed and fully characterized. The ability of iodine to behave as hydrogen bond acceptor and halogen bond donor was held responsible for the orthogonal HB/XB presence. In addition, the structure of Hmim(OMe)I2 was investigated theoretically using MP2/aug-cc-pVDZ level of theory. Natural bond orbital analysis (NBO) was used to investigate the molecular orbitals interactions and orbitals stabilization energies.

Keywords: 1-(2-Methoxyphenyl)-1H-imidazole-2(3H)-thione; Halogen bond; Hydrogen bond; Theoretical calculations; X-ray crystal structure.

MeSH terms

  • Crystallization
  • Crystallography, X-Ray
  • Hydrogen Bonding
  • Imidazoles / chemistry*
  • Iodine / chemistry*
  • Models, Molecular
  • Molecular Structure
  • Quantum Theory
  • Thermodynamics
  • Thiones / chemistry*

Substances

  • 1-(2-methoxyphenyl)-1H-imidazole-2(3H)-thione
  • Imidazoles
  • Thiones
  • Iodine