SYNTHESIS AND CRYSTAL-STRUCTURE OF THE DICHLORO-SELENONITRENE COMPLEX (PPH4)2[WCL5(NSECL2)]

The title compound has been prepared by the reaction of [WCl4(NSeCl)]2 with PPh4Cl in CH2Cl2 solution. It forms red crystals, which were characterized by an X-ray structure determination. Space group P2(1)/c, Z = 4, 3856 observed unique reflections, R = 0.073. Lattice dimensions at 25-degrees-C: a = 2266.0(5), b = 1121.0(2), c = 2013.0(4) pm, beta = 109.66(3)-degrees. The structure consists of PPh4+ ions and anions [WCl5(NSeCl2)]2-, in which the tungsten atom is surrounded in a distorted octahedral way by five chlorine atoms and by the nitrogen atom of the (NSeCl2)3- ligand. The W = N = SeCl2 group is characterized by WN and SeN double bonds; the selenium atom has a pseudo trigonal-bipyramidal coordination with the N atom and two lone pairs in equatorial and the chlorine atoms in axial positions.