CRYSTAL STRUCTURE OF BIS(<i>l</i>-ARGININE)COPPER(II) HEXACHLORODIMERCURATE, [Cu(<i>l</i>-Arg)<sub>2</sub>]Hg<sub>2</sub>Cl<sub>6</sub>
By means of X-ray diffraction the chain structure of [Cu(<i>l</i>-Arg)<sub>2</sub>]Hg<sub>2</sub>Cl<sub>6</sub> (monoclinic, <i>a</i> = 10.2348(9) Å, <i>b</i> = 9.1386(7) Å, <i>c</i> = 14.8521(14) Å, β = 97.455(11)°, space group <i>P</i>2<sub>1</sub>) is established. The chains are formed by square-planar [Cu(<i>l</i>-Arg)<sub>2</sub>]<sup>2+</sup> cations of the type <i>trans</i>-[Cu(N)<sub>2</sub>(О)<sub>2</sub>] (<i>l</i>-Аrg is the zwitter-ion of arginine; Cu-N 1.992 Å and 1.938(6) Å, Cu-O 1.953 Å and 1.967(4) Å) that are bonded to two adjacent binuclear [Cl<sub>2</sub>Hg(μ-Cl)<sub>2</sub>HgCl<sub>2</sub>]<sup>2-</sup> ions through its clorine atoms Cl (Hg-Cl bonds are within 2.34-2.78 Å). With these two additional Cu…Cl contacts Cu adopts the geometry of an elongated octahedron with two apical Cl (Cu-Cl 2.961 Å and 3.064(3) Å).