Inorganic Chemistry, Vol.34, No.10, 2678-2683, 1995
High-Yield Synthesis of the W6S8 Cluster Unit as the Pyridine Complex (W6S8)(PY)(6) and Attempts to Prepare Tungsten Analogs of the Chevrel Phases
A convenient high-yield synthesis of W6Cl12 has been devised from the reaction of WCl4 with iron powder at 500 degrees C. Conversion to (W6S8)(py)(6), py = pyridine, is effected in essentially quantitative yield by reaction of W6Cl12 with NaSH and NaO-n-Bu in 1:12:6 mol ratio in refluxing pyridine (115 degrees C). Black crystals of the insoluble complex (W6S8)(py)(6) were grown from pyridine solution in a sealed tube at 200 degrees C : triclinic, P $($) over bar$$ 1; a = 9.397(2), b = 11.932(3), c = 10.624(2) Angstrom; alpha = 114.28(1), beta = 108.88(1), gamma = 91.19(2)degrees; Z = 1; R(R(w)) = 0.0267 (0.0359). The average bond distances in the cluster molecule, W-W = 2.6617(2), W-S = 2.458(3), and W-N = 2.255(5) Angstrom, are similar to those in Mo6S8(py)(6). IR spectra show strong bands at 378 cm(-1), attributable to the T-1u W-S stretching modes, and 232 cm(-1) of uncertain assignment. Several unsuccessful approaches to deligation of (W6S8)(py)(6), in efforts to prepare W6S8 and M(x)W(6)S(8) analogs of the Chevrel phases, are discussed. Sulfidation of W6Cl12 With variable ratios of NaSH and NaO-n-Bu provided evidence for materials with mixed sulfide-chloride cluster units of average composition [(W6Cl6S2)Cl-2(PY)(4)]. 5py and (W6Cl2S6)(py)(6).
Keywords:MOLECULAR-MODEL;DERIVATIVES