Structure dependence on redox state and charge in [Fe4(μ3-S4)(η-C5H5)4]m[M(mnt)2]n (M = Ni or Pt, m, n = 1 or 2)

The complex salts [Fe4(μ3-S)4(η-C5H5)4]m[M(mnt)2]n {M = Ni, n = 2, m = 1 1; n = 1, m = 1 2 or 2 3: M = Pt, n = 2, m = 1 4; n = 1, m = 1 5 or 2 6; mnt = S2C2(CN)2} have been synthesized by stoichiometric reactions between [NEt4]n[M(mnt)2] (n = 1 or 2, M = Ni or Pt) and [Fe4(μ3-S)4(η-C5H5)4][PF6]n (n = 1 or 2); the salts 2–6 have been structurally characterised. The molecular structures of the [Fe4(μ3-S)4(η-C5H5)4]z+ (z = 1 or 2) cations and the [M(mnt)2]z− (M = Ni or Pt, z = 1 or 2) anions show mean Fe⋯Fe and M–S distances characteristic of z. The isostructural salts [Fe4(μ3-S)4(η-C5H5)4]2[M(mnt)2] (M = Ni 3 or Pt 6) comprise two monocations and one dianion; the planar anions, which form a ruffled ribbon arrangement, are interleaved by the near-spherical cations. The structure of [Fe4(μ3-S)4(η-C5H5)4][Pt(mnt)2]2, 4, with two monoanions and one dication, has face-to-face metal–metal pairs of [Pt(mnt)2]− ions separated by individual [Pt(mnt)2]− units, leading to anion layers interleaved by layers of cations. Salts 2 and 5 have very different structures. The nickel complex [Fe4(μ3-S)4(η-C5H5)4][Ni(mnt)2] 2 comprises dications and dianions whereas the platinum complex [Fe4(μ3-S)4(η-C5H5)4][Pt(mnt)2] 5 has monocations and monoanions. In salt 2 the dianions are well separated while in 5 the monoanions are weakly dimerised.