Zinc(II), cadmium(II), and mercury(II) halide coordination compounds with 1,8‐bis(2‐pyridyl)‐3,6‐dithiaoctane. The crystal and molecular structure of Hg2(C16H20N2S2)Br4

We describe the synthesis and characterization (by elemental analysis, conductance measurements and 1H NMR and IR spectrometry) of compounds with the general formulae M(bpdto) X2 (M = Zn, X = Cl, Br or I; M = Cd, X = Cl or Br) and M2(bpdto)X4 (M = Cd, X = I; M = Hg, X = Cl, Br or I) (bpdto = 1,8‐bis(2‐pyridyl)‐3,6‐dithiaoctane). In addition, the structure of Hg2(bpdto)Br4 was determined by single crystal structure analysis and refined to a conventional R factor of 0.079. Hg2(C16H20N2S2)Br4 crystallized in the monoclinic space group P21/c with a = 14.410(3), b = 6.209(5), c = 14.478(5) Å, β = 113.98(1)° and Z = 4. The molecule was found to have two mercury atoms, each tetrahedrally coordinated to two bromide anions [Hg--Br 2.502(1) and 2,501(2) Å], and to one nitrogen atom [Hg--N 2.366(8) Å] and one sulphur atom [Hg--S 2.670(3) Å] of the ligand molecule, which acted as a bridge between the two metal atoms