Re-S compounds should be even better catalysts for the desulfurization of crude oil than the long proven MoS compounds. The first step in the development of a catalyst, the synthesis of a discrete ReS cluster anion, has now been accomplished. Reaction of a perrhenate solution reduced with NH₂OH·HCl with an aqueous polysulfide solution yielded an NH₄-salt of the cluster anion [Re₄S₂₂]⁴⁻ 1.

References

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3 IR (solid; CsI disk): ca. 3500 (m) (v(H₂O)), ca. 3150 (m) (v_as(NH)), 1600 (m) (δ(H₂O)), 1400 (s) (δ_as(NH)), (ca. 500 (m, br) (H₂O-libration), 465 (m) (v_as(SS), F₂), 339 (m) (v_as(Re₄S₄), F₂), 230 (m); Raman (solid; A = 647.1 nm): 460 (br) (v_s(S-S), A₁), 185 (s) (v_s(Re₄S₄), A₁); UV/VIS (solid, reflectance/cellulose standard): λ≈600 (sh), ≈440 (sh), ≈350 nm.
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4 Strong reflections at d = 880, 763, 538, 459, 400, 349, 311, 293, 257, 253, 240, 232, 229, 219, 213, 198 pm. The measured diagram is in very good agreement with that calculated from the data of the single crystal X-ray structure analysis regarding positions of reflections and their intensities.
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5 1 crystallizes in the space group F 43m; a = 1518.1(3) pm, V = 3498.7 x 10⁶ pm³, Z = 4, ρ_calc = 2.94 g cm⁻³. Empirical absorption correction; solution of structure by heavy atom methods; R = 0.047 for 191 independent reflections (F_o)3.92σ(F_o)); Syntex P2₁ diffractometer, Mo_kα radiation, graphite monochromator. Further details of the crystal structure investigations of 1 and 2 [9] are available on request from the Fachinformationszentrum Energie, Physik, Mathematik GmbH, D-7514 EggensteinLeopoldshafen 2, on quoting the depository number CSD-51 671, the names of the authors, and the full citation of the journal.
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6 In the crystal,[Re₄S₂₂]^4- has the site symmetry 43m(T_d).S3 is disordered at two positions, 69.1 pm above and below the Re-S2-S2c-Rec plane.
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9 Note added in proof (Februar 14, 1986): The chloride-free compound (NH₄)₄[Re₄S₂₂].2H₂O (2) has now been obtained by reaction of ammonium perrhenate with an aqueous polysulfide solution at ca. 60°C. In this case, S acts as a reducing agent. The bond lengths and angles determined for 2 by X-ray structure analysis resemble those of 1.
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