| Summary: | The synthesis and crystal structures of two organometallic electron-transfer salts, [Fe(C5Me5)2]x{Mo[S2C 2(CF3)2]3} (x = 1, 2), are reported. For x = 1 the structure consists of discrete linear stacks of alternating S = 1/2 [Fe(C5Me5)2].1 cations and S = 1/2 {Mo[S2C2(CF3)2]3} .- anions with the anions adopting a nearly perfect trigonal prismatic geometry. Crystal data: monoclinic, space group C2/m, a = 22.551 (3) AΔ, b = 12.997 (2) AΔ, c = 14.236 (4) AΔ, β = 91.23 (2)°, V = 4171.4 AΔ3, Z = 4, R = 7.3%, and Rw = 8.3% at 25°C. The high-temperature magnetic susceptibilities for polycrystalline samples of [M(C5Me5)2].+{Mo[S2C 2(CF3)2]3).- (M = Cr, Fe) and [Fe(C5H5)2].+{Mo[S2C 2(CF3)2]3}.- can be fit to the Curie-Weiss law χ = C/(T - θ), with θ = +1.0, +8.4, and +1.8 K and μeff = 4.32, 3.85, and 3.37 μB, respectively. The positive θ are characteristic of weak ferromagnetic interactions, and the μeff are consistent with independent spins contributing to the magnetic susceptibility. For x = 2, the structure contains interpenetrating linear arrays of alternating S = 1/2 [Fe(C5Me5)2].+ cations and S = 0 (Mo[S2C2(CF3)2]3} 2-~ anions; the anion geometry is significantly distorted from the trigonal prismatic limit, apparently owing to crystal packing forces. Crystal data: triclinic, space group P1, a = 11.426 (3) Å, b = 11.799 (4) Å, c = 23.375 (3) Å, α = 94.78 (2)°, β = 94.62 (2)°, γ = 103.77 (2)°, V = 3033.6 Å3, Z = 2, R = 6.3%, and Rw = 7.4% at 25°C. The magnetic susceptibility for polycrystalline samples of [Fe(C5Me5)2]2{Mo[S2C 2(CF3)2]3} can be fit to the Curie-Weiss law with θ = -3.2 K and μeff = 3.55 μB, indicating that weak intermolecular antiferromagnetic interactions exist between the S = 1/2 [Fe(C5Me5)2].+ cations and that the {Mo[S2C2(CF3)2]3} 2- dianion is diamagnetic. The susceptibility of {[Fe(C5H5)2].+} 2{Mo[S2C2(CF3)2] 3}2- obeys the Curie-Weiss law with θ = 2.53 K and μeff = 4.37 μB, whereas [NiIV(C5Me5)2] 2+{Mo[S2C2(CF3)2] 3}2- is diamagnetic. © 1990 American Chemical Society.
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