Synthesis and crystal structure of PPh4[ReF2Cl2(N2S2)]

PPh4[ReF2Cl2(N2S2)] has been prepared by the reaction of PPh4[ReCl4(NSCl)2]xCH2Cl2 with sodium fluoride in acetonitrile suspension. The compound forms black crystals, which were characterized by IR spectroscopy as well as by an X-ray structure determination. Space group P21/c, Z=4, 2525 observed unique reflexions, R = 0.053. Lattice dimensions at 20deg C: a=1277.4(3), b=713.2(3), c=2860.8(4) pm, β=97.20(3)deg. The compound consists of PPh4+ and [ReF2Cl2(N2S2)]- ions, in which the rhenium atom is surrounded octahedrally by two fluorine atoms, two chlorine atoms, and by the nitrogen atoms of a ReN2S2 five-membered ring, the fluorine ligands being in trans position to the N atoms. The bond lengths ReN (172; 177 pm) and NS (155; 160 pm) are in the range of double bonds, the S-S bond is relatively long (243 pm). (orig.)