Synthesis and crystal structure of a novel tetranuclear cluster [(η5-C5Me5)WS3Cu3Br(Py)3(dppm)](PF6)

In the presence of NH4PF6, reaction of [PPh4][(eta(5)-C5Me5)WS3Cu3Br(dppm)] with excess pyridine afforded red prismatic crystals, [{eta(5)-C5Me5)WS3Cu3Br(Py)(3)(dppm)] (PF6) (1). It was characterized by elemental analysis, IR, UV-vis and H-1 NMR spectroscopy and X-ray diffraction. 1 crystallizes in an orthorhombic system with space group Pna2(1) and unit cell parameters a = 2.1124 (4) nm, b = 1.8944 (4) nm, c = 1.3338 (2) nm, V = 5.337509) nm(3), Z = 4, D-c = 1.807g (.) cm(-3), M-r = 1452.42, F(000) = 2864, mu = 4.342mm(-1), R-1 = 0.0487, wR(2) = 0.1027. The structure of the cluster cation contains an incomplete cubane-like WS3Cu3 core where Cu(1) and Cu(2) atoms are bridged by a dppm ligand. Each of the three Cu atoms adopts a distorted tetrahedral coordination geometry. The W-Cu(1), W-Cu(2) and W-Cu(3) distances are 0.27698(17) nm, 0.2772(17) nm, and 0.27065(9)nm, respectively.