A reaction has been found and investigated that demonstrates the potential for coordination, activation, and transformation of three organic molecules, namely, two dichloromethane molecules and one amine molecule, in the coordination sphere of the [(µ‐H)Os3(CO)10]– carbonylate anion, which is formed in situ from the deprotonation of [(µ‐H)2Os3(CO)10]. This reaction is very intricate and comprises such steps as the nucleophilic substitution of chloride ions by cluster carbonylate anions in the halocarbons, C–H, C–N, and C–Cl bond cleavage, and C–C and C–N bond formation under unusually mild conditions for such reactions leading to the formation of the CH=CH2‐ or CH=CHNR2‐bearing complexes [(µ‐Cl)Os3(µ2‐σ,π‐CH=CH2)(CO)10] and [(µ‐H)Os3(µ‐CH=CHNR2)(CO)10]. The reaction is sensitive to the nature of the halogen in the halocarbon. When bromine or iodine was used in place of chlorine in the halohydrocarbons, [(µ‐H)Os3(µ‐X)(CO)10] (X = Br, I) clusters were obtained in good yields, which apparently indicates the replacement of the SN2 mechanism by SN2Hal.

The reductive action of the bulky SmII formamidinate complex [Sm(dippForm)2(thf)2] (dippForm− = HC(Ndipp)2 −, dipp = 2,6-diisopropylphenyl; thf = tetrahydrofuran) (1) on a series of phosphine chalcogenides (R3PE = Ph3PO, Ph3PS, Ph3PSe, n Bu3PS, n Bu3PSe) as well as Ph3AsS, has been investigated. The reactions are fast for the phosphine derivatives with E = Se and for Ph3AsS, and slow for the phosphine sulfides. They lead to mixtures of binuclear mono- and dichalcogenide complexes [(Sm(dippForm)2)2(µ-En )] (E = S (2), Se (3); n = 1, 2). The ratio of species with (µ-E) or (µ-η2:η2-E2) bridges depends on the nature of the chalcogenide reactant and its concentration, but even under its local excess the formation of the monochalcogenide is preferential. Both types of species form isostructural solid solutions. The dense outer packing of dippForm ligands in the complexes 2 and 3, leaving enough free space in the centre of the molecule, is thought to be the main reason for the geometrical similarity of mono- and dichalcogenides and for their ready co-crystallization. A reaction scheme is proposed, involving the coordination of the starting chalcogenide to the SmII centre with successive formation of E-centered transient radical species [Sm(dippForm)2(E˙)]. Contrary to the phosphine/arsine sulfides and selenides, the product of phosphine oxide coordination, [Sm(dippForm)2(OPPh3)] (4), was shown to be stable, while a similar complex with two phosphine oxide ligands, [Sm(dippForm)2(OPPh3)2] (5), was fortuitously crystallized at lower temperatures.

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