Two 1-(2-Furoyl)-3-phenylthiourea derivatives: Synthesis, characterization and structural study from X-ray powder diffraction using simulated annealing

1-(2-furoyl)-3-p-cyanophenylthiourea (1) and 1-(2-furoyl)-3-o-fluorophenylthiourea (2) were synthesized by converting 2-furoyl chloride into 2-furoyl isothiocyanate and then condensing with the appropriated aniline derivatives. Both products were characterized by elemental analysis, Fourier transform infrared spectroscopy, Raman, ¹H, ¹³C nuclear magnetic resonance and ab initio X-ray powder structure analysis. Compound 1 crystallizes in the monoclinic space group P2₁/n with unit cell dimensions a = 23.169(2) Å, b = 11.353(2) Å, c = 4.798(3) Å, β = 90.30(2)°, V = 1,259.87(3) ų, Z = 4, R _p = 4.62, and R _wp = 7.86. Compound 2 crystallizes also in the monoclinic space group P2₁/n with unit cell dimensions a = 12.072(1) Å, b = 20.801(2) Å, c = 4.737(2) Å, β = 93.34(2)°, V = 1,189.62(3) ų, Z = 4, R _p = 3.95, and R _wp = 7.06. The crystal structures have been determined from laboratory X-ray powder diffraction data using direct space global optimization strategy (simulated annealing) followed by the Rietveld refinement. The thiourea group makes a dihedral angle of 9.4(5)° and 33.5(4)° with the furoyl group in 1 and 2, respectively. In both compounds, the trans-cis geometry of the thiourea unit is stabilized by intramolecular N-H⋯O hydrogen bond between the H atom of the cis thioamide and the carbonyl O atom. In the crystal structure of compound 1, molecules are linked by intermolecular N-H⋯S bonds, forming one-dimensional chains along the c axis. For compound 2, only Van der Waals interactions are observed in the crystal structure, forming one-dimensional chains along the b axis. Graphical Abstract: Crystal structure analysis from X-ray powder diffraction data and spectroscopic characterization of two 1-(2-furoyl)-3-phenylthiourea derivatives.[Figure not available: see fulltext.]