The rational synthesis of tetranuclear heterometallic butterfly clusters: reactions of [M2(CO)6(μ-pyS)2] (M = Re, Mn) with group VIII metal carbonyls

Heating [Os3(CO)10(NCMe)2] with [M2(CO)6(μ-pyS)2] (M = Re, Mn) (1–2) in benzene affords tetranuclear mixed-metal butterfly clusters [MOs3(CO)13(μ3-pyS)] (3–4). Similar reactions with Ru3(CO)12 give [MRu3(CO)13(μ3-pyS)] (5–6); however, when the latter is carried out in toluene the tetraruthenium sulfido cluster [Ru4(CO)12(μ-py)2(μ4-S)] (7) is the major product. Treatment of Fe3(CO)12 with 1 in refluxing toluene affords the mixed-metal sulfido cluster, [Fe2Re2(CO)13(μ-py)(μ-pyS)(μ4-S)] (8), while a similar reaction with 2 furnishes the tetrairon cluster [Fe4(CO)12(μ-py)2(μ4-S)] (9). Addition of PPh3 to 3 in the presence of Me3NO affords both the mono- and bis(phosphine)-substituted products [ReOs3(CO)12(PPh3)(μ3-pyS)] (10) and [ReOs3(CO)11(PPh3)2(μ3-pyS)] (11), respectively. All new complexes have been characterized by a combination of spectroscopic data and single-crystal X-ray diffraction studies.