Dinuclear and polymeric Hg(II) complexes with 1-(2-furoyl)thiourea derivatives: Their crystal structure and related properties

• Published in: Polyhedron 2015-09, Vol.97, p.148-156
• Main Authors: Estévez-Hernández, O., Duque, J., Rodríguez-Hernández, J., Reguera, E.
• Format: Article
• Language: English
• Subjects: Crystal structure; Furoylthioureas; Mercury(II) complexes; Simulated annealing; Spectroscopic characterization
• ISSN: 0277-5387
• DOI: 10.1016/j.poly.2015.05.028

Dimeric and polymeric complexes were prepared by reaction of HgCl2 with 1-(2-furoyl)thiourea derivatives in ethanol. Their structures were determined from X-ray powder diffraction data using direct space global optimization strategy (simulated annealing) followed by the Rietveld refinement. [Display omitted] Dimeric and polymeric complexes bis{[(1-(2-furoyl)-3-bencyl-3-phenylthiourea-κS)chloromercury(II)]-μ-chloro} (HgCl2-FBFT) and catena-poly{[(1-(2-furoyl)-3-bencylthiourea-κS)chloromercury(II)]-μ-chloro} (HgCl2-FBT) were prepared by reaction of HgCl2 with 1-(2-furoyl)-3-bencyl-3-phenylthiourea (FBFT) and 1-(2-furoyl)-3-bencylthiourea (FBT) in ethanol. Their crystal structures were solved and refined from X-ray powder diffraction data using direct space global optimization strategy (simulated annealing) followed by the Rietveld refinement. Both solids exhibit 1:1 metal:ligand stoichiometry and a distorted tetrahedral geometry for the coordination mercury centers. The mercury(II) complexes were characterized by elemental analysis, Raman, NMR and TG-DTG data. Complex HgCl2-FBFT crystallizes in the triclinic system, space group P1¯, while HgCl2-FBT crystallizes in the orthorhombic system, space group Pcnn. In the dimeric complex HgCl2-FBFT each Hg(II) atom is found coordinated to S atom of ligand, and to a terminal and two bridging chlorine atoms. Neighboring dimers remain together in the solid through dipolar and quadrupolar interactions. The complex HgCl2-FBT is a polymer of mercury(II) bridged to two chlorine ions and also coordinated by terminal chlorine ion and a molecule of ligand through the S atom. This compound exhibits intramolecular and intermolecular hydrogen bonds; these last ones are responsible for packing of the polymeric chains in a 3D framework. The photoluminescence properties indicate that both complexes are fluorescent materials with maximum emission at 425nm.