SYNTHESIS AND STRUCTURE OF POTASSIUM TETRAETHYLAMMONIUM HEXATHIOCYANATOPLATINATE(IV)

Abstract

Potassium tetraethylammonium hexathiocyanatoplatinate(IV) (Et4N)(K)[Pt(SCN)6] (I) was synthesized by the reaction of potassium hexathiocyanatoplatinate(IV) with tetraethylammonium chloride in acetonitrile aqueous solution. Slow evaporation of the solvent led to the formation of large red-brown crystals. The product structure was determined by XRDA. The X-ray diffraction pattern of crystal I was carried out on a Bruker D8 QUEST diffractometer (MoKα radiation, λ = 0.71073 Å, graphite monochromator). [С14H20N7KPtS6, M = 712.92, Crystal system monoclinic, space group C 2/c, a = 10.432(8), b = 14.767(13), c = 16.300(13) Å, V = 2510(4) Å3, Z = 4, µ = 6.272 mm-1, F(000) = 1384, crystal size 0.86×0.66×0.50 mm]. The tetrahedral configuration of the tetraethylammonium cation is slightly distorted (CNC angles are 105.5(5)º-111.8(4)º, bond lengths N-С are 1.503(5)-1.519(5) Å). Platinum ions in anions have octahedral coordination (trans-angles SPtS are 180º, cis-angles SPtS are (88.47(4)º-91.53(4)º). The bond lengths Pt-S are equal to 2.373 (2)-2.37(2) Å. Potassium cations are coordinated by six nitrogen atoms of thiocyanate groups (distances N K (2.828(4)-2.896 (4) Å). Trans-angles NKN (128.44 (15)º-146.9 (2)º) are far from ideal values for the octahedron. Bridged thiocyanate ligands are bonded cations of the platinum and potassium. Ambidentate thiocyanate ligands are simultaneously coordinated to the K+ cation by nitrogen atoms. By means of the bridged thiocyanate ligands a three-dimensional coordination polymer is formed. The resulting structure is a three-dimensional grid, in the cells of which the cations of tetraethylammonium (Et4N)+ are located.