Binuclear complexes [Fe2(µ-S2ER2)(CO)6] (ER2 = SiMe2 (Iа), SiEt2 (Ib), SnEt2 (Ic)), promising precursors of heterometallic clusters, were synthesized. Reactions of these complexes with transition metal halide complexes, [Cp"RhCl2]2 (Cp" = η5-C5H3tBu2), [(Dppe)NiCl2] (Dppe = Ph2PCH2CH2PPh2), [(Ph3P)AuCl], and [Mn(CO)5Cl], were studied. The reactions gave heterometallic clusters [Fe2Rh(µ3-S)2(CO)6Cp"] (II), [Fe2Ni(µ3-S)2(CO)6(Dppe)] (III), [Fe2(CO)6(µ-SSnClEt2)(µ-SAu(PPh3))] (IV), [Fe2(CO)6(µ4,η2-S2SnEt2){Mn(CO)4Cl}2] (V), and [Fe2Mn(CO)9Mn(CO)5(µ3-S)(µ4-S)] (VI). Cluster V was found to be converted to VI upon photochemical activation. The structures of compounds I–VI were determined by X-ray diffraction (CIF file CCDC nos. 751214 (Ic), 751215 (III·0.5C7H8), 2062206 (V), 2062207 (Ib), 2062208 (Ia), 2062209 (IV·0.5CH3C5H9).

An attempt to prepare a hybrid clusteroclathrochelate by nucleophilic substitution of iron(II) dichloroclathrochelate by substitution of its chlorine atoms with the [Fe2(μ-S)2(CO)6]2– cluster dianion as a nucleophilic agent generated in situ by the reduction of Fe2(μ-S2)(CO)6 with lithium triethylborohydride unexpectedly gave the macrobicyclic complex with two inherent thiol groups as the single clathrochelate product. Obviously, the initial iron-sulfide cluster underwent a complete decomposition during the reaction, thus acting only as a source of HS– and S2– anions. The composition and the structure of the complex obtained were confirmed by elemental analysis, MALDI-TOF mass spectrometry, 1H and 13C{1H} NMR spectroscopy, and single crystal X-ray diffraction (CIF file CCDC 1585112). The encapsulated iron(II) ion is located at the centre of its FeN6 coordination polyhedron possessing the geometry intermediate between a trigonal prism (the distortion angle φ = 0°) and a trigonal antiprism (φ = 60°) with φ ≈ 25°; the height of this polyhedron is 2.33 Å. The presence of two thiol groups in the vicinal positions of the same ribbed moiety of the macrobicyclic molecule substantially affects the crystal packing of the molecular crystal containing clathrochelate dimers formed by four hydrogen bonds of two types (i.e., two S–H···O and two S–H···N bonds). The obtained cage complex and its deprotonated forms seem to be promising cis-disulfide bridging or chelating ligand synthons for the synthesis of new types of polynuclear complexes and coordination polymers as well.

The reaction of the [Fe2(CO)6(μ-S)2]2− anion (prepared in situ by reduction of [Fe2(CO)6(μ-S2)] with Na/K alloy) with [Cp″RhCl2]2 (Cp″ = η5-(1,3-But 2)C5H3) and [Cp*Ir(CH3CN)3](CF3SO3)2 (Cp* is pentamethylcyclopentadienide) yielded new heterometallic clusters [Fe2(MCp x )(CO)6(μ3-S)2]. The core of the resulting clusters can be described as the distorted [Fe2S2M] square pyramid with the M atom in the apical position. The structures of the clusters were established by X-ray diffraction.