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)

Geometry variation of complex ions in crystals †

“…The dimolybdenum ion has been the subject of some careful studies in which the effect of environment on the length of the metal-metal "bond" is pronounced. 34 Similarly the variability of the Fe ؒ ؒ ؒ Fe distances in the individual [Fe 4 S 4 Cp 4 ] ϩ system has been noted 35,36 and may be ascribed to the weak and variable Fe-Fe bonding in these clusters. In these cases the deformability of the metal-metal distances is a consequence of a rather flexible electronic structure.…”

On the Electronic Origins of Structural Isomerism in the Iron−Sulfur Cubane, [(C5H5)4Fe4S4]2+

“…Perhaps the most ubiquitous of these are the cyclopentadienyl-capped species, (C 5 H 5 ) 4 M 4 E 4 (E ) O,S) (Chart 1), which are known for the majority of the transition metals. [7][8][9][10][11][12][13][14][15][16][17][18][19][20][21][22] The available crystallographic data, collected in Table 1, show tions into their electronic structure. 14,23 The Dahl model is based on the concept that each metal center contributes three orbitals (the t 2g set of an idealized octahedron) to the bonding manifold.…”

“…The story was further complicated by a recent report from Orpen and co-workers, where the [(C 5 H 5 ) 4 Fe 4 S 4 ] 2+ cation was crystallized with two additional counterions, [Ni(mnt) 2 ] 2and [Pt(mnt) 2 ] 1-, mnt ) S 2 C 2 (CN) 2 (Chart 2). 15 (19) Amarasekera, J.; Rauchfuss, T. B.; Wilson, S. R. In the presence of [Ni(mnt) 2 ] 2-, the [(C 5 H 5 ) 4 Fe 4 S 4 ] 2+ cluster adopts a D 2 -symmetric structure with two short, two intermediate, and two long bonds. With a [Pt(mnt) 2 ] 1counterion, in contrast, two independent [(C 5 H 5 ) 4 Fe 4 S 4 ] 2+ cations are found in the unit cell, both of which have C 2 symmetry.…”

“…The electronic structure of iron−sulfur clusters continues to attract a great deal of attention in the literature, largely in the context of biological electron transfer processes. − Even before their biological role was fully appreciated, however, the intrinsic appeal of highly symmetric clusters of metal ions had inspired a number of researchers to synthesize and study a wide range of metal cubanes. Perhaps the most ubiquitous of these are the cyclopentadienyl-capped species, (C 5 H 5 ) 4 M 4 E 4 (E = O,S) (Chart ), which are known for the majority of the transition metals. −

1 Structure of a Cyclopentadienyl-Capped Cubane Cluster

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Metallocenium salts of perhalophenylplatinate anions: ion shape, charge and solvation effects on crystal structure

“…There are three groups of structures that demonstrate the effect of cation size and shape ( [1,9,13], [2,10,14], and [3,11]). Unfortunately, the structures of the first two groups contain different lattice solvation, preventing direct structural comparisons; the varying volume occupied by the solvent may influence the different packing arrangements.…”