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(l-Arg)2]Hg2Cl6 (monoclinic, a = 10.2348(9) Å, b = 9.1386(7) Å, c = 14.8521(14) Å, β = 97.455(11)°, space group P21) is established. The chains are formed by square-planar [Cu(l-Arg)2]2+ cations of the type trans-[Cu(N)2(О)2] (l-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 [Cl2Hg(μ-Cl)2HgCl2]2- 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).