Two new 1D zigzag Hg(II) nanostructure coordination polymers: Sonochemical synthesis, thermal study, crystal structure and Hirshfeld surface analysis

Abstract

Reaction of mercury(II) chloride and bromide with a Schiff base ligand based on isonicotinohydrazide (L) yielded two new 1D zigzag coordination polymers; [Hg(μ-L)Cl2]n (1) and [Hg(μ-L)Br2]n (2). The Schiff base ligand and its Hg(II) complexes have been characterized by FT-IR, UV–Vis, 1H and 13C NMR spectroscopy. The structures of the complexes were determined by single crystal X-ray diffraction. Structural data show that the two new mercury complexes have similar structures. In both complexes, Hg(II) ion is five-coordinated by three atoms of Schiff base ligand and two halide anions. The ligand (L) acts as N2O-donor and connects neighboring Hg ion centers to form infinite 1D zigzag chain. This 1D chain is stabilized as 3D supramolecular network by intermolecular interactions of π⋯π stacking and X–H⋯Cl (X=N and C) in 1 and C–H⋯π, π⋯π stacking and X–H⋯Br (X=N and C) in 2. Hirshfeld surface analysis and 2D fingerprint plots of asymmetric units of two complexes indicated differences and similarities between crystal packing of compounds. TG/DTG analyses show that compounds 1 and 2 decompose completely during three or four thermal steps, respectively. Nanostructure forms of the titled coordination polymers have been also synthesized by sonochemical method and confirmed by X-ray powder diffraction (XRD), and scanning electron microscopy (SEM).