SYNTHESIS, CHARACTERIZATION, CRYSTAL STRUCTURE, AND PROPERTIES OF A MERCURY(II) COMPLEX CONTAINING DMIT LIGAND AND N,N′-ETHYLIDENEDIPYRIDIUM CATION

A new mercury( II) complex containing dmit ligand and biquaternary ammonium cation, DPyE[ Hg( dmit) 2] ( 1) ( DPyE2+ = N, N'-ethylidenedipyridinium, dmit = 1,3-dithiol- 2-thione4,5- dithiolate), was synthesized and fully characterized by elemental analysis, IR, 1H-NMR, UV-Vis, TG, single crystal X-ray diffraction, and powder X-ray diffraction. Moreover, the electrochemical properties and conductivities of complex 1 were studied by cyclic voltammetry and four-probe AC technique, respectively. Complex 1 crystallizes in the monoclinic space group P 21/ n with a = 8.1815( 2) angstrom, b = 12.8701( 5) angstrom, c = 23.2681( 7)angstrom, beta = 90.922( 3)degrees, Z = 4, V = 2449.75( 14) angstrom 3, Dc = 2.114 g center dot cm-3. The crystal structure shows that the dihedral angle of two dmit ligands of [ Hg( dmit) 2] 2- anion is closed to vertical, which results in the formation of a distorted HgS4 tetrahedral geometry. The S center dot center dot center dot S short contacts assemble [ Hg( dmit) 2] 2anions into 1D, 2D, and 3D supramolecular network. The DPyE2+ cations are located in the caves, providing additional stabilization to crystal packing via C- H center dot center dot center dot S hydrogen bonds to [ Hg( dmit) 2] 2- anions. The crystal packing of 1 is characterized by face-to- face pi-pi contacts between DPyE2+ cations and [ Hg( dmit) 2] 2- anions, which result in two orthogonally oriented and mixed stacking columns. These stacking columns interweave into a 2D network, which is further connected to a 3D network via interplanar S center dot center dot center dot S contacts. In addition, the temperaturedependent conductivity in the range of 50- 300 K reveals semi-conducting properties of complex 1, and a room temperature conductivity of 1.53 x 10(-3) S cm- 1 is observed.