A New Class of Binuclear and Trinuclear Iron−Sulfur Clusters Derived from Bis[bis(trimethylsilyl)amido]iron(II)

The compound Fe[N(SiMe3)2]2 is shown to be a useful precursor to dinuclear and trinuclear iron−sulfur−silylamido complexes by reaction with thiols or thiols and sulfur in tetrahydrofuran (THF) or toluene. Reaction with 1 equiv of p-tolylthiol affords [Fe2(μ2-S-p-tol)2(N(SiMe3)2)2(THF)2] (1); with 0.5 equiv of adamantane-1-thiol, [Fe2(μ2-S-1-Ad)(μ2-N(SiMe3)2)(N(SiMe3)2)2] (2) is formed. The clusters [Fe3(μ3-Q)(μ2-SR)3(N(SiMe3)2)3] are available by three methods: (i) self-assembly in the systems Fe[N(SiMe3)2]2/RSH/S or Se [Q = S, R = p-tol (3) and 1-Ad (5)]; (ii) reaction of 1 with Q = S or Se to yield 3 or [Fe3Se(S-p-tol)3(N(SiMe3)2)3] (4); (iii) reaction of 2 with 1-AdSH and S to give 5. Structures of 1−5 are presented. Complexes 1 and 2 contain planar Fe2S2 and Fe2SN rhombs. Clusters 3−5 contain a mixed-valence Fe3Q(SR)3 core with trigonal (cuboidal) geometry. Of known iron−sulfur clusters, these most closely resemble previously reported [Fe3S(S−R−S)3]2− stabilized by bidentate thiolate ligands. Complexes 1−5, together with a small set of recently described clusters of nuclearities 2, 4, and 8, constitute a new class of iron−sulfur−silylamido clusters. Complexes 3−5 constitute a new structure type of mixed-valence iron−sulfur clusters.